drivers/scsi/st.c

   1 /*
   2    SCSI Tape Driver for Linux version 1.1 and newer. See the accompanying
   3    file Documentation/scsi/st.txt for more information.
   4
   5    History:
   6    Rewritten from Dwayne Forsyth's SCSI tape driver by Kai Makisara.
   7    Contribution and ideas from several people including (in alphabetical
   8    order) Klaus Ehrenfried, Eugene Exarevsky, Eric Lee Green, Wolfgang Denk,
   9    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
  10    Michael Schaefer, J"org Weule, and Eric Youngdale.
  11
  12    Copyright 1992 - 2016 Kai Makisara
  13    email Kai.Makisara@kolumbus.fi
  14
  15    Some small formal changes - aeb, 950809
  16
  17    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  18  */
  19
  20 static const char *verstr = "20160209";
  21
  22 #include <linux/module.h>
  23
  24 #include <linux/fs.h>
  25 #include <linux/kernel.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/mm.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <linux/slab.h>
  31 #include <linux/errno.h>
  32 #include <linux/mtio.h>
  33 #include <linux/cdrom.h>
  34 #include <linux/ioctl.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/blkdev.h>
  38 #include <linux/moduleparam.h>
  39 #include <linux/cdev.h>
  40 #include <linux/idr.h>
  41 #include <linux/delay.h>
  42 #include <linux/mutex.h>
  43
  44 #include <linux/uaccess.h>
  45 #include <asm/dma.h>
  46
  47 #include <scsi/scsi.h>
  48 #include <scsi/scsi_dbg.h>
  49 #include <scsi/scsi_device.h>
  50 #include <scsi/scsi_driver.h>
  51 #include <scsi/scsi_eh.h>
  52 #include <scsi/scsi_host.h>
  53 #include <scsi/scsi_ioctl.h>
  54 #include <scsi/sg.h>
  55
  56
  57 /* The driver prints some debugging information on the console if DEBUG
  58    is defined and non-zero. */
  59 #define DEBUG 1
  60 #define NO_DEBUG 0
  61
  62 #define ST_DEB_MSG  KERN_NOTICE
  63 #if DEBUG
  64 /* The message level for the debug messages is currently set to KERN_NOTICE
  65    so that people can easily see the messages. Later when the debugging messages
  66    in the drivers are more widely classified, this may be changed to KERN_DEBUG. */
  67 #define DEB(a) a
  68 #define DEBC(a) if (debugging) { a ; }
  69 #else
  70 #define DEB(a)
  71 #define DEBC(a)
  72 #endif
  73
  74 #define ST_KILOBYTE 1024
  75
  76 #include "st_options.h"
  77 #include "st.h"
  78
  79 static int buffer_kbs;
  80 static int max_sg_segs;
  81 static int try_direct_io = TRY_DIRECT_IO;
  82 static int try_rdio = 1;
  83 static int try_wdio = 1;
  84 static int debug_flag;
  85
  86 static struct class st_sysfs_class;
  87 static const struct attribute_group *st_dev_groups[];
  88 static const struct attribute_group *st_drv_groups[];
  89
  90 MODULE_AUTHOR("Kai Makisara");
  91 MODULE_DESCRIPTION("SCSI tape (st) driver");
  92 MODULE_LICENSE("GPL");
  93 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_TAPE_MAJOR);
  94 MODULE_ALIAS_SCSI_DEVICE(TYPE_TAPE);
  95
  96 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
  97  * of sysfs parameters (which module_param doesn't yet support).
  98  * Sysfs parameters defined explicitly later.
  99  */
 100 module_param_named(buffer_kbs, buffer_kbs, int, 0);
 101 MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size for fixed block mode (KB; 32)");
 102 module_param_named(max_sg_segs, max_sg_segs, int, 0);
 103 MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (256)");
 104 module_param_named(try_direct_io, try_direct_io, int, 0);
 105 MODULE_PARM_DESC(try_direct_io, "Try direct I/O between user buffer and tape drive (1)");
 106 module_param_named(debug_flag, debug_flag, int, 0);
 107 MODULE_PARM_DESC(debug_flag, "Enable DEBUG, same as setting debugging=1");
 108
 109
 110 /* Extra parameters for testing */
 111 module_param_named(try_rdio, try_rdio, int, 0);
 112 MODULE_PARM_DESC(try_rdio, "Try direct read i/o when possible");
 113 module_param_named(try_wdio, try_wdio, int, 0);
 114 MODULE_PARM_DESC(try_wdio, "Try direct write i/o when possible");
 115
 116 #ifndef MODULE
 117 static int write_threshold_kbs;  /* retained for compatibility */
 118 static struct st_dev_parm {
 119         char *name;
 120         int *val;
 121 } parms[] __initdata = {
 122         {
 123                 "buffer_kbs", &buffer_kbs
 124         },
 125         {       /* Retained for compatibility with 2.4 */
 126                 "write_threshold_kbs", &write_threshold_kbs
 127         },
 128         {
 129                 "max_sg_segs", NULL
 130         },
 131         {
 132                 "try_direct_io", &try_direct_io
 133         },
 134         {
 135                 "debug_flag", &debug_flag
 136         }
 137 };
 138 #endif
 139
 140 /* Restrict the number of modes so that names for all are assigned */
 141 #if ST_NBR_MODES > 16
 142 #error "Maximum number of modes is 16"
 143 #endif
 144 /* Bit reversed order to get same names for same minors with all
 145    mode counts */
 146 static const char *st_formats[] = {
 147         "",  "r", "k", "s", "l", "t", "o", "u",
 148         "m", "v", "p", "x", "a", "y", "q", "z"};
 149
 150 /* The default definitions have been moved to st_options.h */
 151
 152 #define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
 153
 154 /* The buffer size should fit into the 24 bits for length in the
 155    6-byte SCSI read and write commands. */
 156 #if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
 157 #error "Buffer size should not exceed (2 << 24 - 1) bytes!"
 158 #endif
 159
 160 static int debugging = DEBUG;
 161
 162 #define MAX_RETRIES 0
 163 #define MAX_WRITE_RETRIES 0
 164 #define MAX_READY_RETRIES 0
 165 #define NO_TAPE  NOT_READY
 166
 167 #define ST_TIMEOUT (900 * HZ)
 168 #define ST_LONG_TIMEOUT (14000 * HZ)
 169
 170 /* Remove mode bits and auto-rewind bit (7) */
 171 #define TAPE_NR(x) ( ((iminor(x) & ~255) >> (ST_NBR_MODE_BITS + 1)) | \
 172     (iminor(x) & ~(-1 << ST_MODE_SHIFT)) )
 173 #define TAPE_MODE(x) ((iminor(x) & ST_MODE_MASK) >> ST_MODE_SHIFT)
 174
 175 /* Construct the minor number from the device (d), mode (m), and non-rewind (n) data */
 176 #define TAPE_MINOR(d, m, n) (((d & ~(255 >> (ST_NBR_MODE_BITS + 1))) << (ST_NBR_MODE_BITS + 1)) | \
 177   (d & (255 >> (ST_NBR_MODE_BITS + 1))) | (m << ST_MODE_SHIFT) | ((n != 0) << 7) )
 178
 179 /* Internal ioctl to set both density (uppermost 8 bits) and blocksize (lower
 180    24 bits) */
 181 #define SET_DENS_AND_BLK 0x10001
 182
 183 static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
 184 static int st_max_sg_segs = ST_MAX_SG;
 185
 186 static int modes_defined;
 187
 188 static int enlarge_buffer(struct st_buffer *, int, int);
 189 static void clear_buffer(struct st_buffer *);
 190 static void normalize_buffer(struct st_buffer *);
 191 static int append_to_buffer(const char __user *, struct st_buffer *, int);
 192 static int from_buffer(struct st_buffer *, char __user *, int);
 193 static void move_buffer_data(struct st_buffer *, int);
 194
 195 static int sgl_map_user_pages(struct st_buffer *, const unsigned int,
 196                               unsigned long, size_t, int);
 197 static int sgl_unmap_user_pages(struct st_buffer *, const unsigned int, int);
 198
 199 static int st_probe(struct device *);
 200 static int st_remove(struct device *);
 201
 202 static struct scsi_driver st_template = {
 203         .gendrv = {
 204                 .name           = "st",
 205                 .owner          = THIS_MODULE,
 206                 .probe          = st_probe,
 207                 .remove         = st_remove,
 208                 .groups         = st_drv_groups,
 209         },
 210 };
 211
 212 static int st_compression(struct scsi_tape *, int);
 213
 214 static int find_partition(struct scsi_tape *);
 215 static int switch_partition(struct scsi_tape *);
 216
 217 static int st_int_ioctl(struct scsi_tape *, unsigned int, unsigned long);
 218
 219 static void scsi_tape_release(struct kref *);
 220
 221 #define to_scsi_tape(obj) container_of(obj, struct scsi_tape, kref)
 222
 223 static DEFINE_MUTEX(st_ref_mutex);
 224 static DEFINE_SPINLOCK(st_index_lock);
 225 static DEFINE_SPINLOCK(st_use_lock);
 226 static DEFINE_IDR(st_index_idr);
 227
 228
 229 \f
 230 #include "osst_detect.h"
 231 #ifndef SIGS_FROM_OSST
 232 #define SIGS_FROM_OSST \
 233         {"OnStream", "SC-", "", "osst"}, \
 234         {"OnStream", "DI-", "", "osst"}, \
 235         {"OnStream", "DP-", "", "osst"}, \
 236         {"OnStream", "USB", "", "osst"}, \
 237         {"OnStream", "FW-", "", "osst"}
 238 #endif
 239
 240 static struct scsi_tape *scsi_tape_get(int dev)
 241 {
 242         struct scsi_tape *STp = NULL;
 243
 244         mutex_lock(&st_ref_mutex);
 245         spin_lock(&st_index_lock);
 246
 247         STp = idr_find(&st_index_idr, dev);
 248         if (!STp) goto out;
 249
 250         kref_get(&STp->kref);
 251
 252         if (!STp->device)
 253                 goto out_put;
 254
 255         if (scsi_device_get(STp->device))
 256                 goto out_put;
 257
 258         goto out;
 259
 260 out_put:
 261         kref_put(&STp->kref, scsi_tape_release);
 262         STp = NULL;
 263 out:
 264         spin_unlock(&st_index_lock);
 265         mutex_unlock(&st_ref_mutex);
 266         return STp;
 267 }
 268
 269 static void scsi_tape_put(struct scsi_tape *STp)
 270 {
 271         struct scsi_device *sdev = STp->device;
 272
 273         mutex_lock(&st_ref_mutex);
 274         kref_put(&STp->kref, scsi_tape_release);
 275         scsi_device_put(sdev);
 276         mutex_unlock(&st_ref_mutex);
 277 }
 278
 279 struct st_reject_data {
 280         char *vendor;
 281         char *model;
 282         char *rev;
 283         char *driver_hint; /* Name of the correct driver, NULL if unknown */
 284 };
 285
 286 static struct st_reject_data reject_list[] = {
 287         /* {"XXX", "Yy-", "", NULL},  example */
 288         SIGS_FROM_OSST,
 289         {NULL, }};
 290
 291 /* If the device signature is on the list of incompatible drives, the
 292    function returns a pointer to the name of the correct driver (if known) */
 293 static char * st_incompatible(struct scsi_device* SDp)
 294 {
 295         struct st_reject_data *rp;
 296
 297         for (rp=&(reject_list[0]); rp->vendor != NULL; rp++)
 298                 if (!strncmp(rp->vendor, SDp->vendor, strlen(rp->vendor)) &&
 299                     !strncmp(rp->model, SDp->model, strlen(rp->model)) &&
 300                     !strncmp(rp->rev, SDp->rev, strlen(rp->rev))) {
 301                         if (rp->driver_hint)
 302                                 return rp->driver_hint;
 303                         else
 304                                 return "unknown";
 305                 }
 306         return NULL;
 307 }
 308 \f
 309
 310 static inline char *tape_name(struct scsi_tape *tape)
 311 {
 312         return tape->disk->disk_name;
 313 }
 314
 315 #define st_printk(prefix, t, fmt, a...) \
 316         sdev_prefix_printk(prefix, (t)->device, tape_name(t), fmt, ##a)
 317 #ifdef DEBUG
 318 #define DEBC_printk(t, fmt, a...) \
 319         if (debugging) { st_printk(ST_DEB_MSG, t, fmt, ##a ); }
 320 #else
 321 #define DEBC_printk(t, fmt, a...)
 322 #endif
 323
 324 static void st_analyze_sense(struct st_request *SRpnt, struct st_cmdstatus *s)
 325 {
 326         const u8 *ucp;
 327         const u8 *sense = SRpnt->sense;
 328
 329         s->have_sense = scsi_normalize_sense(SRpnt->sense,
 330                                 SCSI_SENSE_BUFFERSIZE, &s->sense_hdr);
 331         s->flags = 0;
 332
 333         if (s->have_sense) {
 334                 s->deferred = 0;
 335                 s->remainder_valid =
 336                         scsi_get_sense_info_fld(sense, SCSI_SENSE_BUFFERSIZE, &s->uremainder64);
 337                 switch (sense[0] & 0x7f) {
 338                 case 0x71:
 339                         s->deferred = 1;
 340                 case 0x70:
 341                         s->fixed_format = 1;
 342                         s->flags = sense[2] & 0xe0;
 343                         break;
 344                 case 0x73:
 345                         s->deferred = 1;
 346                 case 0x72:
 347                         s->fixed_format = 0;
 348                         ucp = scsi_sense_desc_find(sense, SCSI_SENSE_BUFFERSIZE, 4);
 349                         s->flags = ucp ? (ucp[3] & 0xe0) : 0;
 350                         break;
 351                 }
 352         }
 353 }
 354
 355
 356 /* Convert the result to success code */
 357 static int st_chk_result(struct scsi_tape *STp, struct st_request * SRpnt)
 358 {
 359         int result = SRpnt->result;
 360         u8 scode;
 361         DEB(const char *stp;)
 362         char *name = tape_name(STp);
 363         struct st_cmdstatus *cmdstatp;
 364
 365         if (!result)
 366                 return 0;
 367
 368         cmdstatp = &STp->buffer->cmdstat;
 369         st_analyze_sense(SRpnt, cmdstatp);
 370
 371         if (cmdstatp->have_sense)
 372                 scode = STp->buffer->cmdstat.sense_hdr.sense_key;
 373         else
 374                 scode = 0;
 375
 376         DEB(
 377         if (debugging) {
 378                 st_printk(ST_DEB_MSG, STp,
 379                             "Error: %x, cmd: %x %x %x %x %x %x\n", result,
 380                             SRpnt->cmd[0], SRpnt->cmd[1], SRpnt->cmd[2],
 381                             SRpnt->cmd[3], SRpnt->cmd[4], SRpnt->cmd[5]);
 382                 if (cmdstatp->have_sense)
 383                         __scsi_print_sense(STp->device, name,
 384                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 385         } ) /* end DEB */
 386         if (!debugging) { /* Abnormal conditions for tape */
 387                 if (!cmdstatp->have_sense)
 388                         st_printk(KERN_WARNING, STp,
 389                                "Error %x (driver bt 0x%x, host bt 0x%x).\n",
 390                                result, driver_byte(result), host_byte(result));
 391                 else if (cmdstatp->have_sense &&
 392                          scode != NO_SENSE &&
 393                          scode != RECOVERED_ERROR &&
 394                          /* scode != UNIT_ATTENTION && */
 395                          scode != BLANK_CHECK &&
 396                          scode != VOLUME_OVERFLOW &&
 397                          SRpnt->cmd[0] != MODE_SENSE &&
 398                          SRpnt->cmd[0] != TEST_UNIT_READY) {
 399
 400                         __scsi_print_sense(STp->device, name,
 401                                            SRpnt->sense, SCSI_SENSE_BUFFERSIZE);
 402                 }
 403         }
 404
 405         if (cmdstatp->fixed_format &&
 406             STp->cln_mode >= EXTENDED_SENSE_START) {  /* Only fixed format sense */
 407                 if (STp->cln_sense_value)
 408                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 409                                                STp->cln_sense_mask) == STp->cln_sense_value);
 410                 else
 411                         STp->cleaning_req |= ((SRpnt->sense[STp->cln_mode] &
 412                                                STp->cln_sense_mask) != 0);
 413         }
 414         if (cmdstatp->have_sense &&
 415             cmdstatp->sense_hdr.asc == 0 && cmdstatp->sense_hdr.ascq == 0x17)
 416                 STp->cleaning_req = 1; /* ASC and ASCQ => cleaning requested */
 417
 418         STp->pos_unknown |= STp->device->was_reset;
 419
 420         if (cmdstatp->have_sense &&
 421             scode == RECOVERED_ERROR
 422 #if ST_RECOVERED_WRITE_FATAL
 423             && SRpnt->cmd[0] != WRITE_6
 424             && SRpnt->cmd[0] != WRITE_FILEMARKS
 425 #endif
 426             ) {
 427                 STp->recover_count++;
 428                 STp->recover_reg++;
 429
 430                 DEB(
 431                 if (debugging) {
 432                         if (SRpnt->cmd[0] == READ_6)
 433                                 stp = "read";
 434                         else if (SRpnt->cmd[0] == WRITE_6)
 435                                 stp = "write";
 436                         else
 437                                 stp = "ioctl";
 438                         st_printk(ST_DEB_MSG, STp,
 439                                   "Recovered %s error (%d).\n",
 440                                   stp, STp->recover_count);
 441                 } ) /* end DEB */
 442
 443                 if (cmdstatp->flags == 0)
 444                         return 0;
 445         }
 446         return (-EIO);
 447 }
 448
 449 static struct st_request *st_allocate_request(struct scsi_tape *stp)
 450 {
 451         struct st_request *streq;
 452
 453         streq = kzalloc(sizeof(*streq), GFP_KERNEL);
 454         if (streq)
 455                 streq->stp = stp;
 456         else {
 457                 st_printk(KERN_ERR, stp,
 458                           "Can't get SCSI request.\n");
 459                 if (signal_pending(current))
 460                         stp->buffer->syscall_result = -EINTR;
 461                 else
 462                         stp->buffer->syscall_result = -EBUSY;
 463         }
 464
 465         return streq;
 466 }
 467
 468 static void st_release_request(struct st_request *streq)
 469 {
 470         kfree(streq);
 471 }
 472
 473 static void st_do_stats(struct scsi_tape *STp, struct request *req)
 474 {
 475         ktime_t now;
 476
 477         now = ktime_get();
 478         if (scsi_req(req)->cmd[0] == WRITE_6) {
 479                 now = ktime_sub(now, STp->stats->write_time);
 480                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_write_time);
 481                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 482                 atomic64_inc(&STp->stats->write_cnt);
 483                 if (scsi_req(req)->result) {
 484                         atomic64_add(atomic_read(&STp->stats->last_write_size)
 485                                 - STp->buffer->cmdstat.residual,
 486                                 &STp->stats->write_byte_cnt);
 487                         if (STp->buffer->cmdstat.residual > 0)
 488                                 atomic64_inc(&STp->stats->resid_cnt);
 489                 } else
 490                         atomic64_add(atomic_read(&STp->stats->last_write_size),
 491                                 &STp->stats->write_byte_cnt);
 492         } else if (scsi_req(req)->cmd[0] == READ_6) {
 493                 now = ktime_sub(now, STp->stats->read_time);
 494                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_read_time);
 495                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 496                 atomic64_inc(&STp->stats->read_cnt);
 497                 if (scsi_req(req)->result) {
 498                         atomic64_add(atomic_read(&STp->stats->last_read_size)
 499                                 - STp->buffer->cmdstat.residual,
 500                                 &STp->stats->read_byte_cnt);
 501                         if (STp->buffer->cmdstat.residual > 0)
 502                                 atomic64_inc(&STp->stats->resid_cnt);
 503                 } else
 504                         atomic64_add(atomic_read(&STp->stats->last_read_size),
 505                                 &STp->stats->read_byte_cnt);
 506         } else {
 507                 now = ktime_sub(now, STp->stats->other_time);
 508                 atomic64_add(ktime_to_ns(now), &STp->stats->tot_io_time);
 509                 atomic64_inc(&STp->stats->other_cnt);
 510         }
 511         atomic64_dec(&STp->stats->in_flight);
 512 }
 513
 514 static void st_scsi_execute_end(struct request *req, blk_status_t status)
 515 {
 516         struct st_request *SRpnt = req->end_io_data;
 517         struct scsi_request *rq = scsi_req(req);
 518         struct scsi_tape *STp = SRpnt->stp;
 519         struct bio *tmp;
 520
 521         STp->buffer->cmdstat.midlevel_result = SRpnt->result = rq->result;
 522         STp->buffer->cmdstat.residual = rq->resid_len;
 523
 524         st_do_stats(STp, req);
 525
 526         tmp = SRpnt->bio;
 527         if (rq->sense_len)
 528                 memcpy(SRpnt->sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
 529         if (SRpnt->waiting)
 530                 complete(SRpnt->waiting);
 531
 532         blk_rq_unmap_user(tmp);
 533         __blk_put_request(req->q, req);
 534 }
 535
 536 static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
 537                            int data_direction, void *buffer, unsigned bufflen,
 538                            int timeout, int retries)
 539 {
 540         struct request *req;
 541         struct scsi_request *rq;
 542         struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
 543         int err = 0;
 544         struct scsi_tape *STp = SRpnt->stp;
 545
 546         req = blk_get_request(SRpnt->stp->device->request_queue,
 547                         data_direction == DMA_TO_DEVICE ?
 548                         REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
 549         if (IS_ERR(req))
 550                 return DRIVER_ERROR << 24;
 551         rq = scsi_req(req);
 552         scsi_req_init(req);
 553         req->rq_flags |= RQF_QUIET;
 554
 555         mdata->null_mapped = 1;
 556
 557         if (bufflen) {
 558                 err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen,
 559                                       GFP_KERNEL);
 560                 if (err) {
 561                         blk_put_request(req);
 562                         return DRIVER_ERROR << 24;
 563                 }
 564         }
 565
 566         atomic64_inc(&STp->stats->in_flight);
 567         if (cmd[0] == WRITE_6) {
 568                 atomic_set(&STp->stats->last_write_size, bufflen);
 569                 STp->stats->write_time = ktime_get();
 570         } else if (cmd[0] == READ_6) {
 571                 atomic_set(&STp->stats->last_read_size, bufflen);
 572                 STp->stats->read_time = ktime_get();
 573         } else {
 574                 STp->stats->other_time = ktime_get();
 575         }
 576
 577         SRpnt->bio = req->bio;
 578         rq->cmd_len = COMMAND_SIZE(cmd[0]);
 579         memset(rq->cmd, 0, BLK_MAX_CDB);
 580         memcpy(rq->cmd, cmd, rq->cmd_len);
 581         req->timeout = timeout;
 582         rq->retries = retries;
 583         req->end_io_data = SRpnt;
 584
 585         blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
 586         return 0;
 587 }
 588
 589 /* Do the scsi command. Waits until command performed if do_wait is true.
 590    Otherwise write_behind_check() is used to check that the command
 591    has finished. */
 592 static struct st_request *
 593 st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd,
 594            int bytes, int direction, int timeout, int retries, int do_wait)
 595 {
 596         struct completion *waiting;
 597         struct rq_map_data *mdata = &STp->buffer->map_data;
 598         int ret;
 599
 600         /* if async, make sure there's no command outstanding */
 601         if (!do_wait && ((STp->buffer)->last_SRpnt)) {
 602                 st_printk(KERN_ERR, STp,
 603                           "Async command already active.\n");
 604                 if (signal_pending(current))
 605                         (STp->buffer)->syscall_result = (-EINTR);
 606                 else
 607                         (STp->buffer)->syscall_result = (-EBUSY);
 608                 return NULL;
 609         }
 610
 611         if (!SRpnt) {
 612                 SRpnt = st_allocate_request(STp);
 613                 if (!SRpnt)
 614                         return NULL;
 615         }
 616
 617         /* If async IO, set last_SRpnt. This ptr tells write_behind_check
 618            which IO is outstanding. It's nulled out when the IO completes. */
 619         if (!do_wait)
 620                 (STp->buffer)->last_SRpnt = SRpnt;
 621
 622         waiting = &STp->wait;
 623         init_completion(waiting);
 624         SRpnt->waiting = waiting;
 625
 626         if (STp->buffer->do_dio) {
 627                 mdata->page_order = 0;
 628                 mdata->nr_entries = STp->buffer->sg_segs;
 629                 mdata->pages = STp->buffer->mapped_pages;
 630         } else {
 631                 mdata->page_order = STp->buffer->reserved_page_order;
 632                 mdata->nr_entries =
 633                         DIV_ROUND_UP(bytes, PAGE_SIZE << mdata->page_order);
 634                 mdata->pages = STp->buffer->reserved_pages;
 635                 mdata->offset = 0;
 636         }
 637
 638         memcpy(SRpnt->cmd, cmd, sizeof(SRpnt->cmd));
 639         STp->buffer->cmdstat.have_sense = 0;
 640         STp->buffer->syscall_result = 0;
 641
 642         ret = st_scsi_execute(SRpnt, cmd, direction, NULL, bytes, timeout,
 643                               retries);
 644         if (ret) {
 645                 /* could not allocate the buffer or request was too large */
 646                 (STp->buffer)->syscall_result = (-EBUSY);
 647                 (STp->buffer)->last_SRpnt = NULL;
 648         } else if (do_wait) {
 649                 wait_for_completion(waiting);
 650                 SRpnt->waiting = NULL;
 651                 (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 652         }
 653
 654         return SRpnt;
 655 }
 656
 657
 658 /* Handle the write-behind checking (waits for completion). Returns -ENOSPC if
 659    write has been correct but EOM early warning reached, -EIO if write ended in
 660    error or zero if write successful. Asynchronous writes are used only in
 661    variable block mode. */
 662 static int write_behind_check(struct scsi_tape * STp)
 663 {
 664         int retval = 0;
 665         struct st_buffer *STbuffer;
 666         struct st_partstat *STps;
 667         struct st_cmdstatus *cmdstatp;
 668         struct st_request *SRpnt;
 669
 670         STbuffer = STp->buffer;
 671         if (!STbuffer->writing)
 672                 return 0;
 673
 674         DEB(
 675         if (STp->write_pending)
 676                 STp->nbr_waits++;
 677         else
 678                 STp->nbr_finished++;
 679         ) /* end DEB */
 680
 681         wait_for_completion(&(STp->wait));
 682         SRpnt = STbuffer->last_SRpnt;
 683         STbuffer->last_SRpnt = NULL;
 684         SRpnt->waiting = NULL;
 685
 686         (STp->buffer)->syscall_result = st_chk_result(STp, SRpnt);
 687         st_release_request(SRpnt);
 688
 689         STbuffer->buffer_bytes -= STbuffer->writing;
 690         STps = &(STp->ps[STp->partition]);
 691         if (STps->drv_block >= 0) {
 692                 if (STp->block_size == 0)
 693                         STps->drv_block++;
 694                 else
 695                         STps->drv_block += STbuffer->writing / STp->block_size;
 696         }
 697
 698         cmdstatp = &STbuffer->cmdstat;
 699         if (STbuffer->syscall_result) {
 700                 retval = -EIO;
 701                 if (cmdstatp->have_sense && !cmdstatp->deferred &&
 702                     (cmdstatp->flags & SENSE_EOM) &&
 703                     (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 704                      cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR)) {
 705                         /* EOM at write-behind, has all data been written? */
 706                         if (!cmdstatp->remainder_valid ||
 707                             cmdstatp->uremainder64 == 0)
 708                                 retval = -ENOSPC;
 709                 }
 710                 if (retval == -EIO)
 711                         STps->drv_block = -1;
 712         }
 713         STbuffer->writing = 0;
 714
 715         DEB(if (debugging && retval)
 716                     st_printk(ST_DEB_MSG, STp,
 717                                 "Async write error %x, return value %d.\n",
 718                                 STbuffer->cmdstat.midlevel_result, retval);) /* end DEB */
 719
 720         return retval;
 721 }
 722
 723
 724 /* Step over EOF if it has been inadvertently crossed (ioctl not used because
 725    it messes up the block number). */
 726 static int cross_eof(struct scsi_tape * STp, int forward)
 727 {
 728         struct st_request *SRpnt;
 729         unsigned char cmd[MAX_COMMAND_SIZE];
 730
 731         cmd[0] = SPACE;
 732         cmd[1] = 0x01;          /* Space FileMarks */
 733         if (forward) {
 734                 cmd[2] = cmd[3] = 0;
 735                 cmd[4] = 1;
 736         } else
 737                 cmd[2] = cmd[3] = cmd[4] = 0xff;        /* -1 filemarks */
 738         cmd[5] = 0;
 739
 740         DEBC_printk(STp, "Stepping over filemark %s.\n",
 741                     forward ? "forward" : "backward");
 742
 743         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
 744                            STp->device->request_queue->rq_timeout,
 745                            MAX_RETRIES, 1);
 746         if (!SRpnt)
 747                 return (STp->buffer)->syscall_result;
 748
 749         st_release_request(SRpnt);
 750         SRpnt = NULL;
 751
 752         if ((STp->buffer)->cmdstat.midlevel_result != 0)
 753                 st_printk(KERN_ERR, STp,
 754                           "Stepping over filemark %s failed.\n",
 755                           forward ? "forward" : "backward");
 756
 757         return (STp->buffer)->syscall_result;
 758 }
 759
 760
 761 /* Flush the write buffer (never need to write if variable blocksize). */
 762 static int st_flush_write_buffer(struct scsi_tape * STp)
 763 {
 764         int transfer, blks;
 765         int result;
 766         unsigned char cmd[MAX_COMMAND_SIZE];
 767         struct st_request *SRpnt;
 768         struct st_partstat *STps;
 769
 770         result = write_behind_check(STp);
 771         if (result)
 772                 return result;
 773
 774         result = 0;
 775         if (STp->dirty == 1) {
 776
 777                 transfer = STp->buffer->buffer_bytes;
 778                 DEBC_printk(STp, "Flushing %d bytes.\n", transfer);
 779
 780                 memset(cmd, 0, MAX_COMMAND_SIZE);
 781                 cmd[0] = WRITE_6;
 782                 cmd[1] = 1;
 783                 blks = transfer / STp->block_size;
 784                 cmd[2] = blks >> 16;
 785                 cmd[3] = blks >> 8;
 786                 cmd[4] = blks;
 787
 788                 SRpnt = st_do_scsi(NULL, STp, cmd, transfer, DMA_TO_DEVICE,
 789                                    STp->device->request_queue->rq_timeout,
 790                                    MAX_WRITE_RETRIES, 1);
 791                 if (!SRpnt)
 792                         return (STp->buffer)->syscall_result;
 793
 794                 STps = &(STp->ps[STp->partition]);
 795                 if ((STp->buffer)->syscall_result != 0) {
 796                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 797
 798                         if (cmdstatp->have_sense && !cmdstatp->deferred &&
 799                             (cmdstatp->flags & SENSE_EOM) &&
 800                             (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
 801                              cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
 802                             (!cmdstatp->remainder_valid ||
 803                              cmdstatp->uremainder64 == 0)) { /* All written at EOM early warning */
 804                                 STp->dirty = 0;
 805                                 (STp->buffer)->buffer_bytes = 0;
 806                                 if (STps->drv_block >= 0)
 807                                         STps->drv_block += blks;
 808                                 result = (-ENOSPC);
 809                         } else {
 810                                 st_printk(KERN_ERR, STp, "Error on flush.\n");
 811                                 STps->drv_block = (-1);
 812                                 result = (-EIO);
 813                         }
 814                 } else {
 815                         if (STps->drv_block >= 0)
 816                                 STps->drv_block += blks;
 817                         STp->dirty = 0;
 818                         (STp->buffer)->buffer_bytes = 0;
 819                 }
 820                 st_release_request(SRpnt);
 821                 SRpnt = NULL;
 822         }
 823         return result;
 824 }
 825
 826
 827 /* Flush the tape buffer. The tape will be positioned correctly unless
 828    seek_next is true. */
 829 static int flush_buffer(struct scsi_tape *STp, int seek_next)
 830 {
 831         int backspace, result;
 832         struct st_buffer *STbuffer;
 833         struct st_partstat *STps;
 834
 835         STbuffer = STp->buffer;
 836
 837         /*
 838          * If there was a bus reset, block further access
 839          * to this device.
 840          */
 841         if (STp->pos_unknown)
 842                 return (-EIO);
 843
 844         if (STp->ready != ST_READY)
 845                 return 0;
 846         STps = &(STp->ps[STp->partition]);
 847         if (STps->rw == ST_WRITING)     /* Writing */
 848                 return st_flush_write_buffer(STp);
 849
 850         if (STp->block_size == 0)
 851                 return 0;
 852
 853         backspace = ((STp->buffer)->buffer_bytes +
 854                      (STp->buffer)->read_pointer) / STp->block_size -
 855             ((STp->buffer)->read_pointer + STp->block_size - 1) /
 856             STp->block_size;
 857         (STp->buffer)->buffer_bytes = 0;
 858         (STp->buffer)->read_pointer = 0;
 859         result = 0;
 860         if (!seek_next) {
 861                 if (STps->eof == ST_FM_HIT) {
 862                         result = cross_eof(STp, 0);     /* Back over the EOF hit */
 863                         if (!result)
 864                                 STps->eof = ST_NOEOF;
 865                         else {
 866                                 if (STps->drv_file >= 0)
 867                                         STps->drv_file++;
 868                                 STps->drv_block = 0;
 869                         }
 870                 }
 871                 if (!result && backspace > 0)
 872                         result = st_int_ioctl(STp, MTBSR, backspace);
 873         } else if (STps->eof == ST_FM_HIT) {
 874                 if (STps->drv_file >= 0)
 875                         STps->drv_file++;
 876                 STps->drv_block = 0;
 877                 STps->eof = ST_NOEOF;
 878         }
 879         return result;
 880
 881 }
 882 \f
 883 /* Set the mode parameters */
 884 static int set_mode_densblk(struct scsi_tape * STp, struct st_modedef * STm)
 885 {
 886         int set_it = 0;
 887         unsigned long arg;
 888
 889         if (!STp->density_changed &&
 890             STm->default_density >= 0 &&
 891             STm->default_density != STp->density) {
 892                 arg = STm->default_density;
 893                 set_it = 1;
 894         } else
 895                 arg = STp->density;
 896         arg <<= MT_ST_DENSITY_SHIFT;
 897         if (!STp->blksize_changed &&
 898             STm->default_blksize >= 0 &&
 899             STm->default_blksize != STp->block_size) {
 900                 arg |= STm->default_blksize;
 901                 set_it = 1;
 902         } else
 903                 arg |= STp->block_size;
 904         if (set_it &&
 905             st_int_ioctl(STp, SET_DENS_AND_BLK, arg)) {
 906                 st_printk(KERN_WARNING, STp,
 907                           "Can't set default block size to %d bytes "
 908                           "and density %x.\n",
 909                           STm->default_blksize, STm->default_density);
 910                 if (modes_defined)
 911                         return (-EINVAL);
 912         }
 913         return 0;
 914 }
 915
 916
 917 /* Lock or unlock the drive door. Don't use when st_request allocated. */
 918 static int do_door_lock(struct scsi_tape * STp, int do_lock)
 919 {
 920         int retval;
 921
 922         DEBC_printk(STp, "%socking drive door.\n", do_lock ? "L" : "Unl");
 923
 924         retval = scsi_set_medium_removal(STp->device,
 925                         do_lock ? SCSI_REMOVAL_PREVENT : SCSI_REMOVAL_ALLOW);
 926         if (!retval)
 927                 STp->door_locked = do_lock ? ST_LOCKED_EXPLICIT : ST_UNLOCKED;
 928         else
 929                 STp->door_locked = ST_LOCK_FAILS;
 930         return retval;
 931 }
 932
 933
 934 /* Set the internal state after reset */
 935 static void reset_state(struct scsi_tape *STp)
 936 {
 937         int i;
 938         struct st_partstat *STps;
 939
 940         STp->pos_unknown = 0;
 941         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
 942                 STps = &(STp->ps[i]);
 943                 STps->rw = ST_IDLE;
 944                 STps->eof = ST_NOEOF;
 945                 STps->at_sm = 0;
 946                 STps->last_block_valid = 0;
 947                 STps->drv_block = -1;
 948                 STps->drv_file = -1;
 949         }
 950         if (STp->can_partitions) {
 951                 STp->partition = find_partition(STp);
 952                 if (STp->partition < 0)
 953                         STp->partition = 0;
 954                 STp->new_partition = STp->partition;
 955         }
 956 }
 957 \f
 958 /* Test if the drive is ready. Returns either one of the codes below or a negative system
 959    error code. */
 960 #define CHKRES_READY       0
 961 #define CHKRES_NEW_SESSION 1
 962 #define CHKRES_NOT_READY   2
 963 #define CHKRES_NO_TAPE     3
 964
 965 #define MAX_ATTENTIONS    10
 966
 967 static int test_ready(struct scsi_tape *STp, int do_wait)
 968 {
 969         int attentions, waits, max_wait, scode;
 970         int retval = CHKRES_READY, new_session = 0;
 971         unsigned char cmd[MAX_COMMAND_SIZE];
 972         struct st_request *SRpnt = NULL;
 973         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
 974
 975         max_wait = do_wait ? ST_BLOCK_SECONDS : 0;
 976
 977         for (attentions=waits=0; ; ) {
 978                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
 979                 cmd[0] = TEST_UNIT_READY;
 980                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 0, DMA_NONE,
 981                                    STp->long_timeout, MAX_READY_RETRIES, 1);
 982
 983                 if (!SRpnt) {
 984                         retval = (STp->buffer)->syscall_result;
 985                         break;
 986                 }
 987
 988                 if (cmdstatp->have_sense) {
 989
 990                         scode = cmdstatp->sense_hdr.sense_key;
 991
 992                         if (scode == UNIT_ATTENTION) { /* New media? */
 993                                 new_session = 1;
 994                                 if (attentions < MAX_ATTENTIONS) {
 995                                         attentions++;
 996                                         continue;
 997                                 }
 998                                 else {
 999                                         retval = (-EIO);
1000                                         break;
1001                                 }
1002                         }
1003
1004                         if (scode == NOT_READY) {
1005                                 if (waits < max_wait) {
1006                                         if (msleep_interruptible(1000)) {
1007                                                 retval = (-EINTR);
1008                                                 break;
1009                                         }
1010                                         waits++;
1011                                         continue;
1012                                 }
1013                                 else {
1014                                         if ((STp->device)->scsi_level >= SCSI_2 &&
1015                                             cmdstatp->sense_hdr.asc == 0x3a)    /* Check ASC */
1016                                                 retval = CHKRES_NO_TAPE;
1017                                         else
1018                                                 retval = CHKRES_NOT_READY;
1019                                         break;
1020                                 }
1021                         }
1022                 }
1023
1024                 retval = (STp->buffer)->syscall_result;
1025                 if (!retval)
1026                         retval = new_session ? CHKRES_NEW_SESSION : CHKRES_READY;
1027                 break;
1028         }
1029
1030         if (SRpnt != NULL)
1031                 st_release_request(SRpnt);
1032         return retval;
1033 }
1034
1035
1036 /* See if the drive is ready and gather information about the tape. Return values:
1037    < 0   negative error code from errno.h
1038    0     drive ready
1039    1     drive not ready (possibly no tape)
1040 */
1041 static int check_tape(struct scsi_tape *STp, struct file *filp)
1042 {
1043         int i, retval, new_session = 0, do_wait;
1044         unsigned char cmd[MAX_COMMAND_SIZE], saved_cleaning;
1045         unsigned short st_flags = filp->f_flags;
1046         struct st_request *SRpnt = NULL;
1047         struct st_modedef *STm;
1048         struct st_partstat *STps;
1049         struct inode *inode = file_inode(filp);
1050         int mode = TAPE_MODE(inode);
1051
1052         STp->ready = ST_READY;
1053
1054         if (mode != STp->current_mode) {
1055                 DEBC_printk(STp, "Mode change from %d to %d.\n",
1056                             STp->current_mode, mode);
1057                 new_session = 1;
1058                 STp->current_mode = mode;
1059         }
1060         STm = &(STp->modes[STp->current_mode]);
1061
1062         saved_cleaning = STp->cleaning_req;
1063         STp->cleaning_req = 0;
1064
1065         do_wait = ((filp->f_flags & O_NONBLOCK) == 0);
1066         retval = test_ready(STp, do_wait);
1067
1068         if (retval < 0)
1069             goto err_out;
1070
1071         if (retval == CHKRES_NEW_SESSION) {
1072                 STp->pos_unknown = 0;
1073                 STp->partition = STp->new_partition = 0;
1074                 if (STp->can_partitions)
1075                         STp->nbr_partitions = 1; /* This guess will be updated later
1076                                                     if necessary */
1077                 for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1078                         STps = &(STp->ps[i]);
1079                         STps->rw = ST_IDLE;
1080                         STps->eof = ST_NOEOF;
1081                         STps->at_sm = 0;
1082                         STps->last_block_valid = 0;
1083                         STps->drv_block = 0;
1084                         STps->drv_file = 0;
1085                 }
1086                 new_session = 1;
1087         }
1088         else {
1089                 STp->cleaning_req |= saved_cleaning;
1090
1091                 if (retval == CHKRES_NOT_READY || retval == CHKRES_NO_TAPE) {
1092                         if (retval == CHKRES_NO_TAPE)
1093                                 STp->ready = ST_NO_TAPE;
1094                         else
1095                                 STp->ready = ST_NOT_READY;
1096
1097                         STp->density = 0;       /* Clear the erroneous "residue" */
1098                         STp->write_prot = 0;
1099                         STp->block_size = 0;
1100                         STp->ps[0].drv_file = STp->ps[0].drv_block = (-1);
1101                         STp->partition = STp->new_partition = 0;
1102                         STp->door_locked = ST_UNLOCKED;
1103                         return CHKRES_NOT_READY;
1104                 }
1105         }
1106
1107         if (STp->omit_blklims)
1108                 STp->min_block = STp->max_block = (-1);
1109         else {
1110                 memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1111                 cmd[0] = READ_BLOCK_LIMITS;
1112
1113                 SRpnt = st_do_scsi(SRpnt, STp, cmd, 6, DMA_FROM_DEVICE,
1114                                    STp->device->request_queue->rq_timeout,
1115                                    MAX_READY_RETRIES, 1);
1116                 if (!SRpnt) {
1117                         retval = (STp->buffer)->syscall_result;
1118                         goto err_out;
1119                 }
1120
1121                 if (!SRpnt->result && !STp->buffer->cmdstat.have_sense) {
1122                         STp->max_block = ((STp->buffer)->b_data[1] << 16) |
1123                             ((STp->buffer)->b_data[2] << 8) | (STp->buffer)->b_data[3];
1124                         STp->min_block = ((STp->buffer)->b_data[4] << 8) |
1125                             (STp->buffer)->b_data[5];
1126                         if ( DEB( debugging || ) !STp->inited)
1127                                 st_printk(KERN_INFO, STp,
1128                                           "Block limits %d - %d bytes.\n",
1129                                           STp->min_block, STp->max_block);
1130                 } else {
1131                         STp->min_block = STp->max_block = (-1);
1132                         DEBC_printk(STp, "Can't read block limits.\n");
1133                 }
1134         }
1135
1136         memset((void *) &cmd[0], 0, MAX_COMMAND_SIZE);
1137         cmd[0] = MODE_SENSE;
1138         cmd[4] = 12;
1139
1140         SRpnt = st_do_scsi(SRpnt, STp, cmd, 12, DMA_FROM_DEVICE,
1141                            STp->device->request_queue->rq_timeout,
1142                            MAX_READY_RETRIES, 1);
1143         if (!SRpnt) {
1144                 retval = (STp->buffer)->syscall_result;
1145                 goto err_out;
1146         }
1147
1148         if ((STp->buffer)->syscall_result != 0) {
1149                 DEBC_printk(STp, "No Mode Sense.\n");
1150                 STp->block_size = ST_DEFAULT_BLOCK;     /* Educated guess (?) */
1151                 (STp->buffer)->syscall_result = 0;      /* Prevent error propagation */
1152                 STp->drv_write_prot = 0;
1153         } else {
1154                 DEBC_printk(STp,"Mode sense. Length %d, "
1155                             "medium %x, WBS %x, BLL %d\n",
1156                             (STp->buffer)->b_data[0],
1157                             (STp->buffer)->b_data[1],
1158                             (STp->buffer)->b_data[2],
1159                             (STp->buffer)->b_data[3]);
1160
1161                 if ((STp->buffer)->b_data[3] >= 8) {
1162                         STp->drv_buffer = ((STp->buffer)->b_data[2] >> 4) & 7;
1163                         STp->density = (STp->buffer)->b_data[4];
1164                         STp->block_size = (STp->buffer)->b_data[9] * 65536 +
1165                             (STp->buffer)->b_data[10] * 256 + (STp->buffer)->b_data[11];
1166                         DEBC_printk(STp, "Density %x, tape length: %x, "
1167                                     "drv buffer: %d\n",
1168                                     STp->density,
1169                                     (STp->buffer)->b_data[5] * 65536 +
1170                                     (STp->buffer)->b_data[6] * 256 +
1171                                     (STp->buffer)->b_data[7],
1172                                     STp->drv_buffer);
1173                 }
1174                 STp->drv_write_prot = ((STp->buffer)->b_data[2] & 0x80) != 0;
1175                 if (!STp->drv_buffer && STp->immediate_filemark) {
1176                         st_printk(KERN_WARNING, STp,
1177                                   "non-buffered tape: disabling "
1178                                   "writing immediate filemarks\n");
1179                         STp->immediate_filemark = 0;
1180                 }
1181         }
1182         st_release_request(SRpnt);
1183         SRpnt = NULL;
1184         STp->inited = 1;
1185
1186         if (STp->block_size > 0)
1187                 (STp->buffer)->buffer_blocks =
1188                         (STp->buffer)->buffer_size / STp->block_size;
1189         else
1190                 (STp->buffer)->buffer_blocks = 1;
1191         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
1192
1193         DEBC_printk(STp, "Block size: %d, buffer size: %d (%d blocks).\n",
1194                     STp->block_size, (STp->buffer)->buffer_size,
1195                     (STp->buffer)->buffer_blocks);
1196
1197         if (STp->drv_write_prot) {
1198                 STp->write_prot = 1;
1199
1200                 DEBC_printk(STp, "Write protected\n");
1201
1202                 if (do_wait &&
1203                     ((st_flags & O_ACCMODE) == O_WRONLY ||
1204                      (st_flags & O_ACCMODE) == O_RDWR)) {
1205                         retval = (-EROFS);
1206                         goto err_out;
1207                 }
1208         }
1209
1210         if (STp->can_partitions && STp->nbr_partitions < 1) {
1211                 /* This code is reached when the device is opened for the first time
1212                    after the driver has been initialized with tape in the drive and the
1213                    partition support has been enabled. */
1214                 DEBC_printk(STp, "Updating partition number in status.\n");
1215                 if ((STp->partition = find_partition(STp)) < 0) {
1216                         retval = STp->partition;
1217                         goto err_out;
1218                 }
1219                 STp->new_partition = STp->partition;
1220                 STp->nbr_partitions = 1; /* This guess will be updated when necessary */
1221         }
1222
1223         if (new_session) {      /* Change the drive parameters for the new mode */
1224                 STp->density_changed = STp->blksize_changed = 0;
1225                 STp->compression_changed = 0;
1226                 if (!(STm->defaults_for_writes) &&
1227                     (retval = set_mode_densblk(STp, STm)) < 0)
1228                     goto err_out;
1229
1230                 if (STp->default_drvbuffer != 0xff) {
1231                         if (st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer))
1232                                 st_printk(KERN_WARNING, STp,
1233                                           "Can't set default drive "
1234                                           "buffering to %d.\n",
1235                                           STp->default_drvbuffer);
1236                 }
1237         }
1238
1239         return CHKRES_READY;
1240
1241  err_out:
1242         return retval;
1243 }
1244
1245
1246 \f/* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1247    module count. */
1248 static int st_open(struct inode *inode, struct file *filp)
1249 {
1250         int i, retval = (-EIO);
1251         int resumed = 0;
1252         struct scsi_tape *STp;
1253         struct st_partstat *STps;
1254         int dev = TAPE_NR(inode);
1255
1256         /*
1257          * We really want to do nonseekable_open(inode, filp); here, but some
1258          * versions of tar incorrectly call lseek on tapes and bail out if that
1259          * fails.  So we disallow pread() and pwrite(), but permit lseeks.
1260          */
1261         filp->f_mode &= ~(FMODE_PREAD | FMODE_PWRITE);
1262
1263         if (!(STp = scsi_tape_get(dev))) {
1264                 return -ENXIO;
1265         }
1266
1267         filp->private_data = STp;
1268
1269         spin_lock(&st_use_lock);
1270         if (STp->in_use) {
1271                 spin_unlock(&st_use_lock);
1272                 scsi_tape_put(STp);
1273                 DEBC_printk(STp, "Device already in use.\n");
1274                 return (-EBUSY);
1275         }
1276
1277         STp->in_use = 1;
1278         spin_unlock(&st_use_lock);
1279         STp->rew_at_close = STp->autorew_dev = (iminor(inode) & 0x80) == 0;
1280
1281         if (scsi_autopm_get_device(STp->device) < 0) {
1282                 retval = -EIO;
1283                 goto err_out;
1284         }
1285         resumed = 1;
1286         if (!scsi_block_when_processing_errors(STp->device)) {
1287                 retval = (-ENXIO);
1288                 goto err_out;
1289         }
1290
1291         /* See that we have at least a one page buffer available */
1292         if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
1293                 st_printk(KERN_WARNING, STp,
1294                           "Can't allocate one page tape buffer.\n");
1295                 retval = (-EOVERFLOW);
1296                 goto err_out;
1297         }
1298
1299         (STp->buffer)->cleared = 0;
1300         (STp->buffer)->writing = 0;
1301         (STp->buffer)->syscall_result = 0;
1302
1303         STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
1304
1305         STp->dirty = 0;
1306         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
1307                 STps = &(STp->ps[i]);
1308                 STps->rw = ST_IDLE;
1309         }
1310         STp->try_dio_now = STp->try_dio;
1311         STp->recover_count = 0;
1312         DEB( STp->nbr_waits = STp->nbr_finished = 0;
1313              STp->nbr_requests = STp->nbr_dio = STp->nbr_pages = 0; )
1314
1315         retval = check_tape(STp, filp);
1316         if (retval < 0)
1317                 goto err_out;
1318         if ((filp->f_flags & O_NONBLOCK) == 0 &&
1319             retval != CHKRES_READY) {
1320                 if (STp->ready == NO_TAPE)
1321                         retval = (-ENOMEDIUM);
1322                 else
1323                         retval = (-EIO);
1324                 goto err_out;
1325         }
1326         return 0;
1327
1328  err_out:
1329         normalize_buffer(STp->buffer);
1330         spin_lock(&st_use_lock);
1331         STp->in_use = 0;
1332         spin_unlock(&st_use_lock);
1333         if (resumed)
1334                 scsi_autopm_put_device(STp->device);
1335         scsi_tape_put(STp);
1336         return retval;
1337
1338 }
1339 \f
1340
1341 /* Flush the tape buffer before close */
1342 static int st_flush(struct file *filp, fl_owner_t id)
1343 {
1344         int result = 0, result2;
1345         unsigned char cmd[MAX_COMMAND_SIZE];
1346         struct st_request *SRpnt;
1347         struct scsi_tape *STp = filp->private_data;
1348         struct st_modedef *STm = &(STp->modes[STp->current_mode]);
1349         struct st_partstat *STps = &(STp->ps[STp->partition]);
1350
1351         if (file_count(filp) > 1)
1352                 return 0;
1353
1354         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1355                 result = st_flush_write_buffer(STp);
1356                 if (result != 0 && result != (-ENOSPC))
1357                         goto out;
1358         }
1359
1360         if (STp->can_partitions &&
1361             (result2 = switch_partition(STp)) < 0) {
1362                 DEBC_printk(STp, "switch_partition at close failed.\n");
1363                 if (result == 0)
1364                         result = result2;
1365                 goto out;
1366         }
1367
1368         DEBC( if (STp->nbr_requests)
1369                 st_printk(KERN_DEBUG, STp,
1370                           "Number of r/w requests %d, dio used in %d, "
1371                           "pages %d.\n", STp->nbr_requests, STp->nbr_dio,
1372                           STp->nbr_pages));
1373
1374         if (STps->rw == ST_WRITING && !STp->pos_unknown) {
1375                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1376
1377 #if DEBUG
1378                 DEBC_printk(STp, "Async write waits %d, finished %d.\n",
1379                             STp->nbr_waits, STp->nbr_finished);
1380 #endif
1381                 memset(cmd, 0, MAX_COMMAND_SIZE);
1382                 cmd[0] = WRITE_FILEMARKS;
1383                 if (STp->immediate_filemark)
1384                         cmd[1] = 1;
1385                 cmd[4] = 1 + STp->two_fm;
1386
1387                 SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
1388                                    STp->device->request_queue->rq_timeout,
1389                                    MAX_WRITE_RETRIES, 1);
1390                 if (!SRpnt) {
1391                         result = (STp->buffer)->syscall_result;
1392                         goto out;
1393                 }
1394
1395                 if (STp->buffer->syscall_result == 0 ||
1396                     (cmdstatp->have_sense && !cmdstatp->deferred &&
1397                      (cmdstatp->flags & SENSE_EOM) &&
1398                      (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
1399                       cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) &&
1400                      (!cmdstatp->remainder_valid || cmdstatp->uremainder64 == 0))) {
1401                         /* Write successful at EOM */
1402                         st_release_request(SRpnt);
1403                         SRpnt = NULL;
1404                         if (STps->drv_file >= 0)
1405                                 STps->drv_file++;
1406                         STps->drv_block = 0;
1407                         if (STp->two_fm)
1408                                 cross_eof(STp, 0);
1409                         STps->eof = ST_FM;
1410                 }
1411                 else { /* Write error */
1412                         st_release_request(SRpnt);
1413                         SRpnt = NULL;
1414                         st_printk(KERN_ERR, STp,
1415                                   "Error on write filemark.\n");
1416                         if (result == 0)
1417                                 result = (-EIO);
1418                 }
1419
1420                 DEBC_printk(STp, "Buffer flushed, %d EOF(s) written\n", cmd[4]);
1421         } else if (!STp->rew_at_close) {
1422                 STps = &(STp->ps[STp->partition]);
1423                 if (!STm->sysv || STps->rw != ST_READING) {
1424                         if (STp->can_bsr)
1425                                 result = flush_buffer(STp, 0);
1426                         else if (STps->eof == ST_FM_HIT) {
1427                                 result = cross_eof(STp, 0);
1428                                 if (result) {
1429                                         if (STps->drv_file >= 0)
1430                                                 STps->drv_file++;
1431                                         STps->drv_block = 0;
1432                                         STps->eof = ST_FM;
1433                                 } else
1434                                         STps->eof = ST_NOEOF;
1435                         }
1436                 } else if ((STps->eof == ST_NOEOF &&
1437                             !(result = cross_eof(STp, 1))) ||
1438                            STps->eof == ST_FM_HIT) {
1439                         if (STps->drv_file >= 0)
1440                                 STps->drv_file++;
1441                         STps->drv_block = 0;
1442                         STps->eof = ST_FM;
1443                 }
1444         }
1445
1446       out:
1447         if (STp->rew_at_close) {
1448                 result2 = st_int_ioctl(STp, MTREW, 1);
1449                 if (result == 0)
1450                         result = result2;
1451         }
1452         return result;
1453 }
1454
1455
1456 /* Close the device and release it. BKL is not needed: this is the only thread
1457    accessing this tape. */
1458 static int st_release(struct inode *inode, struct file *filp)
1459 {
1460         int result = 0;
1461         struct scsi_tape *STp = filp->private_data;
1462
1463         if (STp->door_locked == ST_LOCKED_AUTO)
1464                 do_door_lock(STp, 0);
1465
1466         normalize_buffer(STp->buffer);
1467         spin_lock(&st_use_lock);
1468         STp->in_use = 0;
1469         spin_unlock(&st_use_lock);
1470         scsi_autopm_put_device(STp->device);
1471         scsi_tape_put(STp);
1472
1473         return result;
1474 }
1475 \f
1476 /* The checks common to both reading and writing */
1477 static ssize_t rw_checks(struct scsi_tape *STp, struct file *filp, size_t count)
1478 {
1479         ssize_t retval = 0;
1480
1481         /*
1482          * If we are in the middle of error recovery, don't let anyone
1483          * else try and use this device.  Also, if error recovery fails, it
1484          * may try and take the device offline, in which case all further
1485          * access to the device is prohibited.
1486          */
1487         if (!scsi_block_when_processing_errors(STp->device)) {
1488                 retval = (-ENXIO);
1489                 goto out;
1490         }
1491
1492         if (STp->ready != ST_READY) {
1493                 if (STp->ready == ST_NO_TAPE)
1494                         retval = (-ENOMEDIUM);
1495                 else
1496                         retval = (-EIO);
1497                 goto out;
1498         }
1499
1500         if (! STp->modes[STp->current_mode].defined) {
1501                 retval = (-ENXIO);
1502                 goto out;
1503         }
1504
1505
1506         /*
1507          * If there was a bus reset, block further access
1508          * to this device.
1509          */
1510         if (STp->pos_unknown) {
1511                 retval = (-EIO);
1512                 goto out;
1513         }
1514
1515         if (count == 0)
1516                 goto out;
1517
1518         DEB(
1519         if (!STp->in_use) {
1520                 st_printk(ST_DEB_MSG, STp,
1521                           "Incorrect device.\n");
1522                 retval = (-EIO);
1523                 goto out;
1524         } ) /* end DEB */
1525
1526         if (STp->can_partitions &&
1527             (retval = switch_partition(STp)) < 0)
1528                 goto out;
1529
1530         if (STp->block_size == 0 && STp->max_block > 0 &&
1531             (count < STp->min_block || count > STp->max_block)) {
1532                 retval = (-EINVAL);
1533                 goto out;
1534         }
1535
1536         if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
1537             !do_door_lock(STp, 1))
1538                 STp->door_locked = ST_LOCKED_AUTO;
1539
1540  out:
1541         return retval;
1542 }
1543
1544
1545 static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
1546                            size_t count, int is_read)
1547 {
1548         int i, bufsize, retval = 0;
1549         struct st_buffer *STbp = STp->buffer;
1550
1551         if (is_read)
1552                 i = STp->try_dio_now && try_rdio;
1553         else
1554                 i = STp->try_dio_now && try_wdio;
1555
1556         if (i && ((unsigned long)buf & queue_dma_alignment(
1557                                         STp->device->request_queue)) == 0) {
1558                 i = sgl_map_user_pages(STbp, STbp->use_sg, (unsigned long)buf,
1559                                        count, (is_read ? READ : WRITE));
1560                 if (i > 0) {
1561                         STbp->do_dio = i;
1562                         STbp->buffer_bytes = 0;   /* can be used as transfer counter */
1563                 }
1564                 else
1565                         STbp->do_dio = 0;  /* fall back to buffering with any error */
1566                 STbp->sg_segs = STbp->do_dio;
1567                 DEB(
1568                      if (STbp->do_dio) {
1569                         STp->nbr_dio++;
1570                         STp->nbr_pages += STbp->do_dio;
1571                      }
1572                 )
1573         } else
1574                 STbp->do_dio = 0;
1575         DEB( STp->nbr_requests++; )
1576
1577         if (!STbp->do_dio) {
1578                 if (STp->block_size)
1579                         bufsize = STp->block_size > st_fixed_buffer_size ?
1580                                 STp->block_size : st_fixed_buffer_size;
1581                 else {
1582                         bufsize = count;
1583                         /* Make sure that data from previous user is not leaked even if
1584                            HBA does not return correct residual */
1585                         if (is_read && STp->sili && !STbp->cleared)
1586                                 clear_buffer(STbp);
1587                 }
1588
1589                 if (bufsize > STbp->buffer_size &&
1590                     !enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
1591                         st_printk(KERN_WARNING, STp,
1592                                   "Can't allocate %d byte tape buffer.\n",
1593                                   bufsize);
1594                         retval = (-EOVERFLOW);
1595                         goto out;
1596                 }
1597                 if (STp->block_size)
1598                         STbp->buffer_blocks = bufsize / STp->block_size;
1599         }
1600
1601  out:
1602         return retval;
1603 }
1604
1605
1606 /* Can be called more than once after each setup_buffer() */
1607 static void release_buffering(struct scsi_tape *STp, int is_read)
1608 {
1609         struct st_buffer *STbp;
1610
1611         STbp = STp->buffer;
1612         if (STbp->do_dio) {
1613                 sgl_unmap_user_pages(STbp, STbp->do_dio, is_read);
1614                 STbp->do_dio = 0;
1615                 STbp->sg_segs = 0;
1616         }
1617 }
1618
1619
1620 /* Write command */
1621 static ssize_t
1622 st_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
1623 {
1624         ssize_t total;
1625         ssize_t i, do_count, blks, transfer;
1626         ssize_t retval;
1627         int undone, retry_eot = 0, scode;
1628         int async_write;
1629         unsigned char cmd[MAX_COMMAND_SIZE];
1630         const char __user *b_point;
1631         struct st_request *SRpnt = NULL;
1632         struct scsi_tape *STp = filp->private_data;
1633         struct st_modedef *STm;
1634         struct st_partstat *STps;
1635         struct st_buffer *STbp;
1636
1637         if (mutex_lock_interruptible(&STp->lock))
1638                 return -ERESTARTSYS;
1639
1640         retval = rw_checks(STp, filp, count);
1641         if (retval || count == 0)
1642                 goto out;
1643
1644         /* Write must be integral number of blocks */
1645         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
1646                 st_printk(KERN_WARNING, STp,
1647                           "Write not multiple of tape block size.\n");
1648                 retval = (-EINVAL);
1649                 goto out;
1650         }
1651
1652         STm = &(STp->modes[STp->current_mode]);
1653         STps = &(STp->ps[STp->partition]);
1654
1655         if (STp->write_prot) {
1656                 retval = (-EACCES);
1657                 goto out;
1658         }
1659
1660
1661         if (STps->rw == ST_READING) {
1662                 retval = flush_buffer(STp, 0);
1663                 if (retval)
1664                         goto out;
1665                 STps->rw = ST_WRITING;
1666         } else if (STps->rw != ST_WRITING &&
1667                    STps->drv_file == 0 && STps->drv_block == 0) {
1668                 if ((retval = set_mode_densblk(STp, STm)) < 0)
1669                         goto out;
1670                 if (STm->default_compression != ST_DONT_TOUCH &&
1671                     !(STp->compression_changed)) {
1672                         if (st_compression(STp, (STm->default_compression == ST_YES))) {
1673                                 st_printk(KERN_WARNING, STp,
1674                                           "Can't set default compression.\n");
1675                                 if (modes_defined) {
1676                                         retval = (-EINVAL);
1677                                         goto out;
1678                                 }
1679                         }
1680                 }
1681         }
1682
1683         STbp = STp->buffer;
1684         i = write_behind_check(STp);
1685         if (i) {
1686                 if (i == -ENOSPC)
1687                         STps->eof = ST_EOM_OK;
1688                 else
1689                         STps->eof = ST_EOM_ERROR;
1690         }
1691
1692         if (STps->eof == ST_EOM_OK) {
1693                 STps->eof = ST_EOD_1;  /* allow next write */
1694                 retval = (-ENOSPC);
1695                 goto out;
1696         }
1697         else if (STps->eof == ST_EOM_ERROR) {
1698                 retval = (-EIO);
1699                 goto out;
1700         }
1701
1702         /* Check the buffer readability in cases where copy_user might catch
1703            the problems after some tape movement. */
1704         if (STp->block_size != 0 &&
1705             !STbp->do_dio &&
1706             (copy_from_user(&i, buf, 1) != 0 ||
1707              copy_from_user(&i, buf + count - 1, 1) != 0)) {
1708                 retval = (-EFAULT);
1709                 goto out;
1710         }
1711
1712         retval = setup_buffering(STp, buf, count, 0);
1713         if (retval)
1714                 goto out;
1715
1716         total = count;
1717
1718         memset(cmd, 0, MAX_COMMAND_SIZE);
1719         cmd[0] = WRITE_6;
1720         cmd[1] = (STp->block_size != 0);
1721
1722         STps->rw = ST_WRITING;
1723
1724         b_point = buf;
1725         while (count > 0 && !retry_eot) {
1726
1727                 if (STbp->do_dio) {
1728                         do_count = count;
1729                 }
1730                 else {
1731                         if (STp->block_size == 0)
1732                                 do_count = count;
1733                         else {
1734                                 do_count = STbp->buffer_blocks * STp->block_size -
1735                                         STbp->buffer_bytes;
1736                                 if (do_count > count)
1737                                         do_count = count;
1738                         }
1739
1740                         i = append_to_buffer(b_point, STbp, do_count);
1741                         if (i) {
1742                                 retval = i;
1743                                 goto out;
1744                         }
1745                 }
1746                 count -= do_count;
1747                 b_point += do_count;
1748
1749                 async_write = STp->block_size == 0 && !STbp->do_dio &&
1750                         STm->do_async_writes && STps->eof < ST_EOM_OK;
1751
1752                 if (STp->block_size != 0 && STm->do_buffer_writes &&
1753                     !(STp->try_dio_now && try_wdio) && STps->eof < ST_EOM_OK &&
1754                     STbp->buffer_bytes < STbp->buffer_size) {
1755                         STp->dirty = 1;
1756                         /* Don't write a buffer that is not full enough. */
1757                         if (!async_write && count == 0)
1758                                 break;
1759                 }
1760
1761         retry_write:
1762                 if (STp->block_size == 0)
1763                         blks = transfer = do_count;
1764                 else {
1765                         if (!STbp->do_dio)
1766                                 blks = STbp->buffer_bytes;
1767                         else
1768                                 blks = do_count;
1769                         blks /= STp->block_size;
1770                         transfer = blks * STp->block_size;
1771                 }
1772                 cmd[2] = blks >> 16;
1773                 cmd[3] = blks >> 8;
1774                 cmd[4] = blks;
1775
1776                 SRpnt = st_do_scsi(SRpnt, STp, cmd, transfer, DMA_TO_DEVICE,
1777                                    STp->device->request_queue->rq_timeout,
1778                                    MAX_WRITE_RETRIES, !async_write);
1779                 if (!SRpnt) {
1780                         retval = STbp->syscall_result;
1781                         goto out;
1782                 }
1783                 if (async_write && !STbp->syscall_result) {
1784                         STbp->writing = transfer;
1785                         STp->dirty = !(STbp->writing ==
1786                                        STbp->buffer_bytes);
1787                         SRpnt = NULL;  /* Prevent releasing this request! */
1788                         DEB( STp->write_pending = 1; )
1789                         break;
1790                 }
1791
1792                 if (STbp->syscall_result != 0) {
1793                         struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1794
1795                         DEBC_printk(STp, "Error on write:\n");
1796                         if (cmdstatp->have_sense && (cmdstatp->flags & SENSE_EOM)) {
1797                                 scode = cmdstatp->sense_hdr.sense_key;
1798                                 if (cmdstatp->remainder_valid)
1799                                         undone = (int)cmdstatp->uremainder64;
1800                                 else if (STp->block_size == 0 &&
1801                                          scode == VOLUME_OVERFLOW)
1802                                         undone = transfer;
1803                                 else
1804                                         undone = 0;
1805                                 if (STp->block_size != 0)
1806                                         undone *= STp->block_size;
1807                                 if (undone <= do_count) {
1808                                         /* Only data from this write is not written */
1809                                         count += undone;
1810                                         b_point -= undone;
1811                                         do_count -= undone;
1812                                         if (STp->block_size)
1813                                                 blks = (transfer - undone) / STp->block_size;
1814                                         STps->eof = ST_EOM_OK;
1815                                         /* Continue in fixed block mode if all written
1816                                            in this request but still something left to write
1817                                            (retval left to zero)
1818                                         */
1819                                         if (STp->block_size == 0 ||
1820                                             undone > 0 || count == 0)
1821                                                 retval = (-ENOSPC); /* EOM within current request */
1822                                         DEBC_printk(STp, "EOM with %d "
1823                                                     "bytes unwritten.\n",
1824                                                     (int)count);
1825                                 } else {
1826                                         /* EOT within data buffered earlier (possible only
1827                                            in fixed block mode without direct i/o) */
1828                                         if (!retry_eot && !cmdstatp->deferred &&
1829                                             (scode == NO_SENSE || scode == RECOVERED_ERROR)) {
1830                                                 move_buffer_data(STp->buffer, transfer - undone);
1831                                                 retry_eot = 1;
1832                                                 if (STps->drv_block >= 0) {
1833                                                         STps->drv_block += (transfer - undone) /
1834                                                                 STp->block_size;
1835                                                 }
1836                                                 STps->eof = ST_EOM_OK;
1837                                                 DEBC_printk(STp, "Retry "
1838                                                             "write of %d "
1839                                                             "bytes at EOM.\n",
1840                                                             STp->buffer->buffer_bytes);
1841                                                 goto retry_write;
1842                                         }
1843                                         else {
1844                                                 /* Either error within data buffered by driver or
1845                                                    failed retry */
1846                                                 count -= do_count;
1847                                                 blks = do_count = 0;
1848                                                 STps->eof = ST_EOM_ERROR;
1849                                                 STps->drv_block = (-1); /* Too cautious? */
1850                                                 retval = (-EIO);        /* EOM for old data */
1851                                                 DEBC_printk(STp, "EOM with "
1852                                                             "lost data.\n");
1853                                         }
1854                                 }
1855                         } else {
1856                                 count += do_count;
1857                                 STps->drv_block = (-1);         /* Too cautious? */
1858                                 retval = STbp->syscall_result;
1859                         }
1860
1861                 }
1862
1863                 if (STps->drv_block >= 0) {
1864                         if (STp->block_size == 0)
1865                                 STps->drv_block += (do_count > 0);
1866                         else
1867                                 STps->drv_block += blks;
1868                 }
1869
1870                 STbp->buffer_bytes = 0;
1871                 STp->dirty = 0;
1872
1873                 if (retval || retry_eot) {
1874                         if (count < total)
1875                                 retval = total - count;
1876                         goto out;
1877                 }
1878         }
1879
1880         if (STps->eof == ST_EOD_1)
1881                 STps->eof = ST_EOM_OK;
1882         else if (STps->eof != ST_EOM_OK)
1883                 STps->eof = ST_NOEOF;
1884         retval = total - count;
1885
1886  out:
1887         if (SRpnt != NULL)
1888                 st_release_request(SRpnt);
1889         release_buffering(STp, 0);
1890         mutex_unlock(&STp->lock);
1891
1892         return retval;
1893 }
1894 \f
1895 /* Read data from the tape. Returns zero in the normal case, one if the
1896    eof status has changed, and the negative error code in case of a
1897    fatal error. Otherwise updates the buffer and the eof state.
1898
1899    Does release user buffer mapping if it is set.
1900 */
1901 static long read_tape(struct scsi_tape *STp, long count,
1902                       struct st_request ** aSRpnt)
1903 {
1904         int transfer, blks, bytes;
1905         unsigned char cmd[MAX_COMMAND_SIZE];
1906         struct st_request *SRpnt;
1907         struct st_modedef *STm;
1908         struct st_partstat *STps;
1909         struct st_buffer *STbp;
1910         int retval = 0;
1911
1912         if (count == 0)
1913                 return 0;
1914
1915         STm = &(STp->modes[STp->current_mode]);
1916         STps = &(STp->ps[STp->partition]);
1917         if (STps->eof == ST_FM_HIT)
1918                 return 1;
1919         STbp = STp->buffer;
1920
1921         if (STp->block_size == 0)
1922                 blks = bytes = count;
1923         else {
1924                 if (!(STp->try_dio_now && try_rdio) && STm->do_read_ahead) {
1925                         blks = (STp->buffer)->buffer_blocks;
1926                         bytes = blks * STp->block_size;
1927                 } else {
1928                         bytes = count;
1929                         if (!STbp->do_dio && bytes > (STp->buffer)->buffer_size)
1930                                 bytes = (STp->buffer)->buffer_size;
1931                         blks = bytes / STp->block_size;
1932                         bytes = blks * STp->block_size;
1933                 }
1934         }
1935
1936         memset(cmd, 0, MAX_COMMAND_SIZE);
1937         cmd[0] = READ_6;
1938         cmd[1] = (STp->block_size != 0);
1939         if (!cmd[1] && STp->sili)
1940                 cmd[1] |= 2;
1941         cmd[2] = blks >> 16;
1942         cmd[3] = blks >> 8;
1943         cmd[4] = blks;
1944
1945         SRpnt = *aSRpnt;
1946         SRpnt = st_do_scsi(SRpnt, STp, cmd, bytes, DMA_FROM_DEVICE,
1947                            STp->device->request_queue->rq_timeout,
1948                            MAX_RETRIES, 1);
1949         release_buffering(STp, 1);
1950         *aSRpnt = SRpnt;
1951         if (!SRpnt)
1952                 return STbp->syscall_result;
1953
1954         STbp->read_pointer = 0;
1955         STps->at_sm = 0;
1956
1957         /* Something to check */
1958         if (STbp->syscall_result) {
1959                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
1960
1961                 retval = 1;
1962                 DEBC_printk(STp,
1963                             "Sense: %2x %2x %2x %2x %2x %2x %2x %2x\n",
1964                             SRpnt->sense[0], SRpnt->sense[1],
1965                             SRpnt->sense[2], SRpnt->sense[3],
1966                             SRpnt->sense[4], SRpnt->sense[5],
1967                             SRpnt->sense[6], SRpnt->sense[7]);
1968                 if (cmdstatp->have_sense) {
1969
1970                         if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
1971                                 cmdstatp->flags &= 0xcf;        /* No need for EOM in this case */
1972
1973                         if (cmdstatp->flags != 0) { /* EOF, EOM, or ILI */
1974                                 /* Compute the residual count */
1975                                 if (cmdstatp->remainder_valid)
1976                                         transfer = (int)cmdstatp->uremainder64;
1977                                 else
1978                                         transfer = 0;
1979                                 if (cmdstatp->sense_hdr.sense_key == MEDIUM_ERROR) {
1980                                         if (STp->block_size == 0)
1981                                                 transfer = bytes;
1982                                         /* Some drives set ILI with MEDIUM ERROR */
1983                                         cmdstatp->flags &= ~SENSE_ILI;
1984                                 }
1985
1986                                 if (cmdstatp->flags & SENSE_ILI) {      /* ILI */
1987                                         if (STp->block_size == 0 &&
1988                                             transfer < 0) {
1989                                                 st_printk(KERN_NOTICE, STp,
1990                                                           "Failed to read %d "
1991                                                           "byte block with %d "
1992                                                           "byte transfer.\n",
1993                                                           bytes - transfer,
1994                                                           bytes);
1995                                                 if (STps->drv_block >= 0)
1996                                                         STps->drv_block += 1;
1997                                                 STbp->buffer_bytes = 0;
1998                                                 return (-ENOMEM);
1999                                         } else if (STp->block_size == 0) {
2000                                                 STbp->buffer_bytes = bytes - transfer;
2001                                         } else {
2002                                                 st_release_request(SRpnt);
2003                                                 SRpnt = *aSRpnt = NULL;
2004                                                 if (transfer == blks) { /* We did not get anything, error */
2005                                                         st_printk(KERN_NOTICE, STp,
2006                                                                   "Incorrect "
2007                                                                   "block size.\n");
2008                                                         if (STps->drv_block >= 0)
2009                                                                 STps->drv_block += blks - transfer + 1;
2010                                                         st_int_ioctl(STp, MTBSR, 1);
2011                                                         return (-EIO);
2012                                                 }
2013                                                 /* We have some data, deliver it */
2014                                                 STbp->buffer_bytes = (blks - transfer) *
2015                                                     STp->block_size;
2016                                                 DEBC_printk(STp, "ILI but "
2017                                                             "enough data "
2018                                                             "received %ld "
2019                                                             "%d.\n", count,
2020                                                             STbp->buffer_bytes);
2021                                                 if (STps->drv_block >= 0)
2022                                                         STps->drv_block += 1;
2023                                                 if (st_int_ioctl(STp, MTBSR, 1))
2024                                                         return (-EIO);
2025                                         }
2026                                 } else if (cmdstatp->flags & SENSE_FMK) {       /* FM overrides EOM */
2027                                         if (STps->eof != ST_FM_HIT)
2028                                                 STps->eof = ST_FM_HIT;
2029                                         else
2030                                                 STps->eof = ST_EOD_2;
2031                                         if (STp->block_size == 0)
2032                                                 STbp->buffer_bytes = 0;
2033                                         else
2034                                                 STbp->buffer_bytes =
2035                                                     bytes - transfer * STp->block_size;
2036                                         DEBC_printk(STp, "EOF detected (%d "
2037                                                     "bytes read).\n",
2038                                                     STbp->buffer_bytes);
2039                                 } else if (cmdstatp->flags & SENSE_EOM) {
2040                                         if (STps->eof == ST_FM)
2041                                                 STps->eof = ST_EOD_1;
2042                                         else
2043                                                 STps->eof = ST_EOM_OK;
2044                                         if (STp->block_size == 0)
2045                                                 STbp->buffer_bytes = bytes - transfer;
2046                                         else
2047                                                 STbp->buffer_bytes =
2048                                                     bytes - transfer * STp->block_size;
2049
2050                                         DEBC_printk(STp, "EOM detected (%d "
2051                                                     "bytes read).\n",
2052                                                     STbp->buffer_bytes);
2053                                 }
2054                         }
2055                         /* end of EOF, EOM, ILI test */
2056                         else {  /* nonzero sense key */
2057                                 DEBC_printk(STp, "Tape error while reading.\n");
2058                                 STps->drv_block = (-1);
2059                                 if (STps->eof == ST_FM &&
2060                                     cmdstatp->sense_hdr.sense_key == BLANK_CHECK) {
2061                                         DEBC_printk(STp, "Zero returned for "
2062                                                     "first BLANK CHECK "
2063                                                     "after EOF.\n");
2064                                         STps->eof = ST_EOD_2;   /* First BLANK_CHECK after FM */
2065                                 } else  /* Some other extended sense code */
2066                                         retval = (-EIO);
2067                         }
2068
2069                         if (STbp->buffer_bytes < 0)  /* Caused by bogus sense data */
2070                                 STbp->buffer_bytes = 0;
2071                 }
2072                 /* End of extended sense test */
2073                 else {          /* Non-extended sense */
2074                         retval = STbp->syscall_result;
2075                 }
2076
2077         }
2078         /* End of error handling */
2079         else {                  /* Read successful */
2080                 STbp->buffer_bytes = bytes;
2081                 if (STp->sili) /* In fixed block mode residual is always zero here */
2082                         STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
2083         }
2084
2085         if (STps->drv_block >= 0) {
2086                 if (STp->block_size == 0)
2087                         STps->drv_block++;
2088                 else
2089                         STps->drv_block += STbp->buffer_bytes / STp->block_size;
2090         }
2091         return retval;
2092 }
2093 \f
2094
2095 /* Read command */
2096 static ssize_t
2097 st_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
2098 {
2099         ssize_t total;
2100         ssize_t retval = 0;
2101         ssize_t i, transfer;
2102         int special, do_dio = 0;
2103         struct st_request *SRpnt = NULL;
2104         struct scsi_tape *STp = filp->private_data;
2105         struct st_modedef *STm;
2106         struct st_partstat *STps;
2107         struct st_buffer *STbp = STp->buffer;
2108
2109         if (mutex_lock_interruptible(&STp->lock))
2110                 return -ERESTARTSYS;
2111
2112         retval = rw_checks(STp, filp, count);
2113         if (retval || count == 0)
2114                 goto out;
2115
2116         STm = &(STp->modes[STp->current_mode]);
2117         if (STp->block_size != 0 && (count % STp->block_size) != 0) {
2118                 if (!STm->do_read_ahead) {
2119                         retval = (-EINVAL);     /* Read must be integral number of blocks */
2120                         goto out;
2121                 }
2122                 STp->try_dio_now = 0;  /* Direct i/o can't handle split blocks */
2123         }
2124
2125         STps = &(STp->ps[STp->partition]);
2126         if (STps->rw == ST_WRITING) {
2127                 retval = flush_buffer(STp, 0);
2128                 if (retval)
2129                         goto out;
2130                 STps->rw = ST_READING;
2131         }
2132         DEB(
2133         if (debugging && STps->eof != ST_NOEOF)
2134                 st_printk(ST_DEB_MSG, STp,
2135                           "EOF/EOM flag up (%d). Bytes %d\n",
2136                           STps->eof, STbp->buffer_bytes);
2137         ) /* end DEB */
2138
2139         retval = setup_buffering(STp, buf, count, 1);
2140         if (retval)
2141                 goto out;
2142         do_dio = STbp->do_dio;
2143
2144         if (STbp->buffer_bytes == 0 &&
2145             STps->eof >= ST_EOD_1) {
2146                 if (STps->eof < ST_EOD) {
2147                         STps->eof += 1;
2148                         retval = 0;
2149                         goto out;
2150                 }
2151                 retval = (-EIO);        /* EOM or Blank Check */
2152                 goto out;
2153         }
2154
2155         if (do_dio) {
2156                 /* Check the buffer writability before any tape movement. Don't alter
2157                    buffer data. */
2158                 if (copy_from_user(&i, buf, 1) != 0 ||
2159                     copy_to_user(buf, &i, 1) != 0 ||
2160                     copy_from_user(&i, buf + count - 1, 1) != 0 ||
2161                     copy_to_user(buf + count - 1, &i, 1) != 0) {
2162                         retval = (-EFAULT);
2163                         goto out;
2164                 }
2165         }
2166
2167         STps->rw = ST_READING;
2168
2169
2170         /* Loop until enough data in buffer or a special condition found */
2171         for (total = 0, special = 0; total < count && !special;) {
2172
2173                 /* Get new data if the buffer is empty */
2174                 if (STbp->buffer_bytes == 0) {
2175                         special = read_tape(STp, count - total, &SRpnt);
2176                         if (special < 0) {      /* No need to continue read */
2177                                 retval = special;
2178                                 goto out;
2179                         }
2180                 }
2181
2182                 /* Move the data from driver buffer to user buffer */
2183                 if (STbp->buffer_bytes > 0) {
2184                         DEB(
2185                         if (debugging && STps->eof != ST_NOEOF)
2186                                 st_printk(ST_DEB_MSG, STp,
2187                                           "EOF up (%d). Left %d, needed %d.\n",
2188                                           STps->eof, STbp->buffer_bytes,
2189                                           (int)(count - total));
2190                         ) /* end DEB */
2191                         transfer = STbp->buffer_bytes < count - total ?
2192                             STbp->buffer_bytes : count - total;
2193                         if (!do_dio) {
2194                                 i = from_buffer(STbp, buf, transfer);
2195                                 if (i) {
2196                                         retval = i;
2197                                         goto out;
2198                                 }
2199                         }
2200                         buf += transfer;
2201                         total += transfer;
2202                 }
2203
2204                 if (STp->block_size == 0)
2205                         break;  /* Read only one variable length block */
2206
2207         }                       /* for (total = 0, special = 0;
2208                                    total < count && !special; ) */
2209
2210         /* Change the eof state if no data from tape or buffer */
2211         if (total == 0) {
2212                 if (STps->eof == ST_FM_HIT) {
2213                         STps->eof = ST_FM;
2214                         STps->drv_block = 0;
2215                         if (STps->drv_file >= 0)
2216                                 STps->drv_file++;
2217                 } else if (STps->eof == ST_EOD_1) {
2218                         STps->eof = ST_EOD_2;
2219                         STps->drv_block = 0;
2220                         if (STps->drv_file >= 0)
2221                                 STps->drv_file++;
2222                 } else if (STps->eof == ST_EOD_2)
2223                         STps->eof = ST_EOD;
2224         } else if (STps->eof == ST_FM)
2225                 STps->eof = ST_NOEOF;
2226         retval = total;
2227
2228  out:
2229         if (SRpnt != NULL) {
2230                 st_release_request(SRpnt);
2231                 SRpnt = NULL;
2232         }
2233         if (do_dio) {
2234                 release_buffering(STp, 1);
2235                 STbp->buffer_bytes = 0;
2236         }
2237         mutex_unlock(&STp->lock);
2238
2239         return retval;
2240 }
2241 \f
2242
2243
2244 DEB(
2245 /* Set the driver options */
2246 static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm)
2247 {
2248         if (debugging) {
2249                 st_printk(KERN_INFO, STp,
2250                           "Mode %d options: buffer writes: %d, "
2251                           "async writes: %d, read ahead: %d\n",
2252                           STp->current_mode, STm->do_buffer_writes,
2253                           STm->do_async_writes, STm->do_read_ahead);
2254                 st_printk(KERN_INFO, STp,
2255                           "    can bsr: %d, two FMs: %d, "
2256                           "fast mteom: %d, auto lock: %d,\n",
2257                           STp->can_bsr, STp->two_fm, STp->fast_mteom,
2258                           STp->do_auto_lock);
2259                 st_printk(KERN_INFO, STp,
2260                           "    defs for wr: %d, no block limits: %d, "
2261                           "partitions: %d, s2 log: %d\n",
2262                           STm->defaults_for_writes, STp->omit_blklims,
2263                           STp->can_partitions, STp->scsi2_logical);
2264                 st_printk(KERN_INFO, STp,
2265                           "    sysv: %d nowait: %d sili: %d "
2266                           "nowait_filemark: %d\n",
2267                           STm->sysv, STp->immediate, STp->sili,
2268                           STp->immediate_filemark);
2269                 st_printk(KERN_INFO, STp, "    debugging: %d\n", debugging);
2270         }
2271 }
2272         )
2273
2274
2275 static int st_set_options(struct scsi_tape *STp, long options)
2276 {
2277         int value;
2278         long code;
2279         struct st_modedef *STm;
2280         struct cdev *cd0, *cd1;
2281         struct device *d0, *d1;
2282
2283         STm = &(STp->modes[STp->current_mode]);
2284         if (!STm->defined) {
2285                 cd0 = STm->cdevs[0];
2286                 cd1 = STm->cdevs[1];
2287                 d0  = STm->devs[0];
2288                 d1  = STm->devs[1];
2289                 memcpy(STm, &(STp->modes[0]), sizeof(struct st_modedef));
2290                 STm->cdevs[0] = cd0;
2291                 STm->cdevs[1] = cd1;
2292                 STm->devs[0]  = d0;
2293                 STm->devs[1]  = d1;
2294                 modes_defined = 1;
2295                 DEBC_printk(STp, "Initialized mode %d definition from mode 0\n",
2296                             STp->current_mode);
2297         }
2298
2299         code = options & MT_ST_OPTIONS;
2300         if (code == MT_ST_BOOLEANS) {
2301                 STm->do_buffer_writes = (options & MT_ST_BUFFER_WRITES) != 0;
2302                 STm->do_async_writes = (options & MT_ST_ASYNC_WRITES) != 0;
2303                 STm->defaults_for_writes = (options & MT_ST_DEF_WRITES) != 0;
2304                 STm->do_read_ahead = (options & MT_ST_READ_AHEAD) != 0;
2305                 STp->two_fm = (options & MT_ST_TWO_FM) != 0;
2306                 STp->fast_mteom = (options & MT_ST_FAST_MTEOM) != 0;
2307                 STp->do_auto_lock = (options & MT_ST_AUTO_LOCK) != 0;
2308                 STp->can_bsr = (options & MT_ST_CAN_BSR) != 0;
2309                 STp->omit_blklims = (options & MT_ST_NO_BLKLIMS) != 0;
2310                 if ((STp->device)->scsi_level >= SCSI_2)
2311                         STp->can_partitions = (options & MT_ST_CAN_PARTITIONS) != 0;
2312                 STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
2313                 STp->immediate = (options & MT_ST_NOWAIT) != 0;
2314                 STp->immediate_filemark = (options & MT_ST_NOWAIT_EOF) != 0;
2315                 STm->sysv = (options & MT_ST_SYSV) != 0;
2316                 STp->sili = (options & MT_ST_SILI) != 0;
2317                 DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
2318                      st_log_options(STp, STm); )
2319         } else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
2320                 value = (code == MT_ST_SETBOOLEANS);
2321                 if ((options & MT_ST_BUFFER_WRITES) != 0)
2322                         STm->do_buffer_writes = value;
2323                 if ((options & MT_ST_ASYNC_WRITES) != 0)
2324                         STm->do_async_writes = value;
2325                 if ((options & MT_ST_DEF_WRITES) != 0)
2326                         STm->defaults_for_writes = value;
2327                 if ((options & MT_ST_READ_AHEAD) != 0)
2328                         STm->do_read_ahead = value;
2329                 if ((options & MT_ST_TWO_FM) != 0)
2330                         STp->two_fm = value;
2331                 if ((options & MT_ST_FAST_MTEOM) != 0)
2332                         STp->fast_mteom = value;
2333                 if ((options & MT_ST_AUTO_LOCK) != 0)
2334                         STp->do_auto_lock = value;
2335                 if ((options & MT_ST_CAN_BSR) != 0)
2336                         STp->can_bsr = value;
2337                 if ((options & MT_ST_NO_BLKLIMS) != 0)
2338                         STp->omit_blklims = value;
2339                 if ((STp->device)->scsi_level >= SCSI_2 &&
2340                     (options & MT_ST_CAN_PARTITIONS) != 0)
2341                         STp->can_partitions = value;
2342                 if ((options & MT_ST_SCSI2LOGICAL) != 0)
2343                         STp->scsi2_logical = value;
2344                 if ((options & MT_ST_NOWAIT) != 0)
2345                         STp->immediate = value;
2346                 if ((options & MT_ST_NOWAIT_EOF) != 0)
2347                         STp->immediate_filemark = value;
2348                 if ((options & MT_ST_SYSV) != 0)
2349                         STm->sysv = value;
2350                 if ((options & MT_ST_SILI) != 0)
2351                         STp->sili = value;
2352                 DEB(
2353                 if ((options & MT_ST_DEBUGGING) != 0)
2354                         debugging = value;
2355                         st_log_options(STp, STm); )
2356         } else if (code == MT_ST_WRITE_THRESHOLD) {
2357                 /* Retained for compatibility */
2358         } else if (code == MT_ST_DEF_BLKSIZE) {
2359                 value = (options & ~MT_ST_OPTIONS);
2360                 if (value == ~MT_ST_OPTIONS) {
2361                         STm->default_blksize = (-1);
2362                         DEBC_printk(STp, "Default block size disabled.\n");
2363                 } else {
2364                         STm->default_blksize = value;
2365                         DEBC_printk(STp,"Default block size set to "
2366                                     "%d bytes.\n", STm->default_blksize);
2367                         if (STp->ready == ST_READY) {
2368                                 STp->blksize_changed = 0;
2369                                 set_mode_densblk(STp, STm);
2370                         }
2371                 }
2372         } else if (code == MT_ST_TIMEOUTS) {
2373                 value = (options & ~MT_ST_OPTIONS);
2374                 if ((value & MT_ST_SET_LONG_TIMEOUT) != 0) {
2375                         STp->long_timeout = (value & ~MT_ST_SET_LONG_TIMEOUT) * HZ;
2376                         DEBC_printk(STp, "Long timeout set to %d seconds.\n",
2377                                     (value & ~MT_ST_SET_LONG_TIMEOUT));
2378                 } else {
2379                         blk_queue_rq_timeout(STp->device->request_queue,
2380                                              value * HZ);
2381                         DEBC_printk(STp, "Normal timeout set to %d seconds.\n",
2382                                     value);
2383                 }
2384         } else if (code == MT_ST_SET_CLN) {
2385                 value = (options & ~MT_ST_OPTIONS) & 0xff;
2386                 if (value != 0 &&
2387                         (value < EXTENDED_SENSE_START ||
2388                                 value >= SCSI_SENSE_BUFFERSIZE))
2389                         return (-EINVAL);
2390                 STp->cln_mode = value;
2391                 STp->cln_sense_mask = (options >> 8) & 0xff;
2392                 STp->cln_sense_value = (options >> 16) & 0xff;
2393                 st_printk(KERN_INFO, STp,
2394                           "Cleaning request mode %d, mask %02x, value %02x\n",
2395                           value, STp->cln_sense_mask, STp->cln_sense_value);
2396         } else if (code == MT_ST_DEF_OPTIONS) {
2397                 code = (options & ~MT_ST_CLEAR_DEFAULT);
2398                 value = (options & MT_ST_CLEAR_DEFAULT);
2399                 if (code == MT_ST_DEF_DENSITY) {
2400                         if (value == MT_ST_CLEAR_DEFAULT) {
2401                                 STm->default_density = (-1);
2402                                 DEBC_printk(STp,
2403                                             "Density default disabled.\n");
2404                         } else {
2405                                 STm->default_density = value & 0xff;
2406                                 DEBC_printk(STp, "Density default set to %x\n",
2407                                             STm->default_density);
2408                                 if (STp->ready == ST_READY) {
2409                                         STp->density_changed = 0;
2410                                         set_mode_densblk(STp, STm);
2411                                 }
2412                         }
2413                 } else if (code == MT_ST_DEF_DRVBUFFER) {
2414                         if (value == MT_ST_CLEAR_DEFAULT) {
2415                                 STp->default_drvbuffer = 0xff;
2416                                 DEBC_printk(STp,
2417                                             "Drive buffer default disabled.\n");
2418                         } else {
2419                                 STp->default_drvbuffer = value & 7;
2420                                 DEBC_printk(STp,
2421                                             "Drive buffer default set to %x\n",
2422                                             STp->default_drvbuffer);
2423                                 if (STp->ready == ST_READY)
2424                                         st_int_ioctl(STp, MTSETDRVBUFFER, STp->default_drvbuffer);
2425                         }
2426                 } else if (code == MT_ST_DEF_COMPRESSION) {
2427                         if (value == MT_ST_CLEAR_DEFAULT) {
2428                                 STm->default_compression = ST_DONT_TOUCH;
2429                                 DEBC_printk(STp,
2430                                             "Compression default disabled.\n");
2431                         } else {
2432                                 if ((value & 0xff00) != 0) {
2433                                         STp->c_algo = (value & 0xff00) >> 8;
2434                                         DEBC_printk(STp, "Compression "
2435                                                     "algorithm set to 0x%x.\n",
2436                                                     STp->c_algo);
2437                                 }
2438                                 if ((value & 0xff) != 0xff) {
2439                                         STm->default_compression = (value & 1 ? ST_YES : ST_NO);
2440                                         DEBC_printk(STp, "Compression default "
2441                                                     "set to %x\n",
2442                                                     (value & 1));
2443                                         if (STp->ready == ST_READY) {
2444                                                 STp->compression_changed = 0;
2445                                                 st_compression(STp, (STm->default_compression == ST_YES));
2446                                         }
2447                                 }
2448                         }
2449                 }
2450         } else
2451                 return (-EIO);
2452
2453         return 0;
2454 }
2455 \f
2456 #define MODE_HEADER_LENGTH  4
2457
2458 /* Mode header and page byte offsets */
2459 #define MH_OFF_DATA_LENGTH     0
2460 #define MH_OFF_MEDIUM_TYPE     1
2461 #define MH_OFF_DEV_SPECIFIC    2
2462 #define MH_OFF_BDESCS_LENGTH   3
2463 #define MP_OFF_PAGE_NBR        0
2464 #define MP_OFF_PAGE_LENGTH     1
2465
2466 /* Mode header and page bit masks */
2467 #define MH_BIT_WP              0x80
2468 #define MP_MSK_PAGE_NBR        0x3f
2469
2470 /* Don't return block descriptors */
2471 #define MODE_SENSE_OMIT_BDESCS 0x08
2472
2473 #define MODE_SELECT_PAGE_FORMAT 0x10
2474
2475 /* Read a mode page into the tape buffer. The block descriptors are included
2476    if incl_block_descs is true. The page control is ored to the page number
2477    parameter, if necessary. */
2478 static int read_mode_page(struct scsi_tape *STp, int page, int omit_block_descs)
2479 {
2480         unsigned char cmd[MAX_COMMAND_SIZE];
2481         struct st_request *SRpnt;
2482
2483         memset(cmd, 0, MAX_COMMAND_SIZE);
2484         cmd[0] = MODE_SENSE;
2485         if (omit_block_descs)
2486                 cmd[1] = MODE_SENSE_OMIT_BDESCS;
2487         cmd[2] = page;
2488         cmd[4] = 255;
2489
2490         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_FROM_DEVICE,
2491                            STp->device->request_queue->rq_timeout, 0, 1);
2492         if (SRpnt == NULL)
2493                 return (STp->buffer)->syscall_result;
2494
2495         st_release_request(SRpnt);
2496
2497         return STp->buffer->syscall_result;
2498 }
2499
2500
2501 /* Send the mode page in the tape buffer to the drive. Assumes that the mode data
2502    in the buffer is correctly formatted. The long timeout is used if slow is non-zero. */
2503 static int write_mode_page(struct scsi_tape *STp, int page, int slow)
2504 {
2505         int pgo;
2506         unsigned char cmd[MAX_COMMAND_SIZE];
2507         struct st_request *SRpnt;
2508         int timeout;
2509
2510         memset(cmd, 0, MAX_COMMAND_SIZE);
2511         cmd[0] = MODE_SELECT;
2512         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2513         pgo = MODE_HEADER_LENGTH + (STp->buffer)->b_data[MH_OFF_BDESCS_LENGTH];
2514         cmd[4] = pgo + (STp->buffer)->b_data[pgo + MP_OFF_PAGE_LENGTH] + 2;
2515
2516         /* Clear reserved fields */
2517         (STp->buffer)->b_data[MH_OFF_DATA_LENGTH] = 0;
2518         (STp->buffer)->b_data[MH_OFF_MEDIUM_TYPE] = 0;
2519         (STp->buffer)->b_data[MH_OFF_DEV_SPECIFIC] &= ~MH_BIT_WP;
2520         (STp->buffer)->b_data[pgo + MP_OFF_PAGE_NBR] &= MP_MSK_PAGE_NBR;
2521
2522         timeout = slow ?
2523                 STp->long_timeout : STp->device->request_queue->rq_timeout;
2524         SRpnt = st_do_scsi(NULL, STp, cmd, cmd[4], DMA_TO_DEVICE,
2525                            timeout, 0, 1);
2526         if (SRpnt == NULL)
2527                 return (STp->buffer)->syscall_result;
2528
2529         st_release_request(SRpnt);
2530
2531         return STp->buffer->syscall_result;
2532 }
2533
2534
2535 #define COMPRESSION_PAGE        0x0f
2536 #define COMPRESSION_PAGE_LENGTH 16
2537
2538 #define CP_OFF_DCE_DCC          2
2539 #define CP_OFF_C_ALGO           7
2540
2541 #define DCE_MASK  0x80
2542 #define DCC_MASK  0x40
2543 #define RED_MASK  0x60
2544
2545
2546 /* Control the compression with mode page 15. Algorithm not changed if zero.
2547
2548    The block descriptors are read and written because Sony SDT-7000 does not
2549    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
2550    Including block descriptors should not cause any harm to other drives. */
2551
2552 static int st_compression(struct scsi_tape * STp, int state)
2553 {
2554         int retval;
2555         int mpoffs;  /* Offset to mode page start */
2556         unsigned char *b_data = (STp->buffer)->b_data;
2557
2558         if (STp->ready != ST_READY)
2559                 return (-EIO);
2560
2561         /* Read the current page contents */
2562         retval = read_mode_page(STp, COMPRESSION_PAGE, 0);
2563         if (retval) {
2564                 DEBC_printk(STp, "Compression mode page not supported.\n");
2565                 return (-EIO);
2566         }
2567
2568         mpoffs = MODE_HEADER_LENGTH + b_data[MH_OFF_BDESCS_LENGTH];
2569         DEBC_printk(STp, "Compression state is %d.\n",
2570                     (b_data[mpoffs + CP_OFF_DCE_DCC] & DCE_MASK ? 1 : 0));
2571
2572         /* Check if compression can be changed */
2573         if ((b_data[mpoffs + CP_OFF_DCE_DCC] & DCC_MASK) == 0) {
2574                 DEBC_printk(STp, "Compression not supported.\n");
2575                 return (-EIO);
2576         }
2577
2578         /* Do the change */
2579         if (state) {
2580                 b_data[mpoffs + CP_OFF_DCE_DCC] |= DCE_MASK;
2581                 if (STp->c_algo != 0)
2582                         b_data[mpoffs + CP_OFF_C_ALGO] = STp->c_algo;
2583         }
2584         else {
2585                 b_data[mpoffs + CP_OFF_DCE_DCC] &= ~DCE_MASK;
2586                 if (STp->c_algo != 0)
2587                         b_data[mpoffs + CP_OFF_C_ALGO] = 0; /* no compression */
2588         }
2589
2590         retval = write_mode_page(STp, COMPRESSION_PAGE, 0);
2591         if (retval) {
2592                 DEBC_printk(STp, "Compression change failed.\n");
2593                 return (-EIO);
2594         }
2595         DEBC_printk(STp, "Compression state changed to %d.\n", state);
2596
2597         STp->compression_changed = 1;
2598         return 0;
2599 }
2600
2601
2602 /* Process the load and unload commands (does unload if the load code is zero) */
2603 static int do_load_unload(struct scsi_tape *STp, struct file *filp, int load_code)
2604 {
2605         int retval = (-EIO), timeout;
2606         unsigned char cmd[MAX_COMMAND_SIZE];
2607         struct st_partstat *STps;
2608         struct st_request *SRpnt;
2609
2610         if (STp->ready != ST_READY && !load_code) {
2611                 if (STp->ready == ST_NO_TAPE)
2612                         return (-ENOMEDIUM);
2613                 else
2614                         return (-EIO);
2615         }
2616
2617         memset(cmd, 0, MAX_COMMAND_SIZE);
2618         cmd[0] = START_STOP;
2619         if (load_code)
2620                 cmd[4] |= 1;
2621         /*
2622          * If arg >= 1 && arg <= 6 Enhanced load/unload in HP C1553A
2623          */
2624         if (load_code >= 1 + MT_ST_HPLOADER_OFFSET
2625             && load_code <= 6 + MT_ST_HPLOADER_OFFSET) {
2626                 DEBC_printk(STp, " Enhanced %sload slot %2d.\n",
2627                             (cmd[4]) ? "" : "un",
2628                             load_code - MT_ST_HPLOADER_OFFSET);
2629                 cmd[3] = load_code - MT_ST_HPLOADER_OFFSET; /* MediaID field of C1553A */
2630         }
2631         if (STp->immediate) {
2632                 cmd[1] = 1;     /* Don't wait for completion */
2633                 timeout = STp->device->request_queue->rq_timeout;
2634         }
2635         else
2636                 timeout = STp->long_timeout;
2637
2638         DEBC(
2639                 if (!load_code)
2640                         st_printk(ST_DEB_MSG, STp, "Unloading tape.\n");
2641                 else
2642                         st_printk(ST_DEB_MSG, STp, "Loading tape.\n");
2643                 );
2644
2645         SRpnt = st_do_scsi(NULL, STp, cmd, 0, DMA_NONE,
2646                            timeout, MAX_RETRIES, 1);
2647         if (!SRpnt)
2648                 return (STp->buffer)->syscall_result;
2649
2650         retval = (STp->buffer)->syscall_result;
2651         st_release_request(SRpnt);
2652
2653         if (!retval) {  /* SCSI command successful */
2654
2655                 if (!load_code) {
2656                         STp->rew_at_close = 0;
2657                         STp->ready = ST_NO_TAPE;
2658                 }
2659                 else {
2660                         STp->rew_at_close = STp->autorew_dev;
2661                         retval = check_tape(STp, filp);
2662                         if (retval > 0)
2663                                 retval = 0;
2664                 }
2665         }
2666         else {
2667                 STps = &(STp->ps[STp->partition]);
2668                 STps->drv_file = STps->drv_block = (-1);
2669         }
2670
2671         return retval;
2672 }
2673 \f
2674 #if DEBUG
2675 #define ST_DEB_FORWARD  0
2676 #define ST_DEB_BACKWARD 1
2677 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd)
2678 {
2679         s32 sc;
2680
2681         if (!debugging)
2682                 return;
2683
2684         sc = cmd[2] & 0x80 ? 0xff000000 : 0;
2685         sc |= (cmd[2] << 16) | (cmd[3] << 8) | cmd[4];
2686         if (direction)
2687                 sc = -sc;
2688         st_printk(ST_DEB_MSG, STp, "Spacing tape %s over %d %s.\n",
2689                   direction ? "backward" : "forward", sc, units);
2690 }
2691 #else
2692 #define ST_DEB_FORWARD  0
2693 #define ST_DEB_BACKWARD 1
2694 static void deb_space_print(struct scsi_tape *STp, int direction, char *units, unsigned char *cmd) {}
2695 #endif
2696
2697
2698 /* Internal ioctl function */
2699 static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned long arg)
2700 {
2701         int timeout;
2702         long ltmp;
2703         int ioctl_result;
2704         int chg_eof = 1;
2705         unsigned char cmd[MAX_COMMAND_SIZE];
2706         struct st_request *SRpnt;
2707         struct st_partstat *STps;
2708         int fileno, blkno, at_sm, undone;
2709         int datalen = 0, direction = DMA_NONE;
2710
2711         WARN_ON(STp->buffer->do_dio != 0);
2712         if (STp->ready != ST_READY) {
2713                 if (STp->ready == ST_NO_TAPE)
2714                         return (-ENOMEDIUM);
2715                 else
2716                         return (-EIO);
2717         }
2718         timeout = STp->long_timeout;
2719         STps = &(STp->ps[STp->partition]);
2720         fileno = STps->drv_file;
2721         blkno = STps->drv_block;
2722         at_sm = STps->at_sm;
2723
2724         memset(cmd, 0, MAX_COMMAND_SIZE);
2725         switch (cmd_in) {
2726         case MTFSFM:
2727                 chg_eof = 0;    /* Changed from the FSF after this */
2728         case MTFSF:
2729                 cmd[0] = SPACE;
2730                 cmd[1] = 0x01;  /* Space FileMarks */
2731                 cmd[2] = (arg >> 16);
2732                 cmd[3] = (arg >> 8);
2733                 cmd[4] = arg;
2734                 deb_space_print(STp, ST_DEB_FORWARD, "filemarks", cmd);
2735                 if (fileno >= 0)
2736                         fileno += arg;
2737                 blkno = 0;
2738                 at_sm &= (arg == 0);
2739                 break;
2740         case MTBSFM:
2741                 chg_eof = 0;    /* Changed from the FSF after this */
2742         case MTBSF:
2743                 cmd[0] = SPACE;
2744                 cmd[1] = 0x01;  /* Space FileMarks */
2745                 ltmp = (-arg);
2746                 cmd[2] = (ltmp >> 16);
2747                 cmd[3] = (ltmp >> 8);
2748                 cmd[4] = ltmp;
2749                 deb_space_print(STp, ST_DEB_BACKWARD, "filemarks", cmd);
2750                 if (fileno >= 0)
2751                         fileno -= arg;
2752                 blkno = (-1);   /* We can't know the block number */
2753                 at_sm &= (arg == 0);
2754                 break;
2755         case MTFSR:
2756                 cmd[0] = SPACE;
2757                 cmd[1] = 0x00;  /* Space Blocks */
2758                 cmd[2] = (arg >> 16);
2759                 cmd[3] = (arg >> 8);
2760                 cmd[4] = arg;
2761                 deb_space_print(STp, ST_DEB_FORWARD, "blocks", cmd);
2762                 if (blkno >= 0)
2763                         blkno += arg;
2764                 at_sm &= (arg == 0);
2765                 break;
2766         case MTBSR:
2767                 cmd[0] = SPACE;
2768                 cmd[1] = 0x00;  /* Space Blocks */
2769                 ltmp = (-arg);
2770                 cmd[2] = (ltmp >> 16);
2771                 cmd[3] = (ltmp >> 8);
2772                 cmd[4] = ltmp;
2773                 deb_space_print(STp, ST_DEB_BACKWARD, "blocks", cmd);
2774                 if (blkno >= 0)
2775                         blkno -= arg;
2776                 at_sm &= (arg == 0);
2777                 break;
2778         case MTFSS:
2779                 cmd[0] = SPACE;
2780                 cmd[1] = 0x04;  /* Space Setmarks */
2781                 cmd[2] = (arg >> 16);
2782                 cmd[3] = (arg >> 8);
2783                 cmd[4] = arg;
2784                 deb_space_print(STp, ST_DEB_FORWARD, "setmarks", cmd);
2785                 if (arg != 0) {
2786                         blkno = fileno = (-1);
2787                         at_sm = 1;
2788                 }
2789                 break;
2790         case MTBSS:
2791                 cmd[0] = SPACE;
2792                 cmd[1] = 0x04;  /* Space Setmarks */
2793                 ltmp = (-arg);
2794                 cmd[2] = (ltmp >> 16);
2795                 cmd[3] = (ltmp >> 8);
2796                 cmd[4] = ltmp;
2797                 deb_space_print(STp, ST_DEB_BACKWARD, "setmarks", cmd);
2798                 if (arg != 0) {
2799                         blkno = fileno = (-1);
2800                         at_sm = 1;
2801                 }
2802                 break;
2803         case MTWEOF:
2804         case MTWEOFI:
2805         case MTWSM:
2806                 if (STp->write_prot)
2807                         return (-EACCES);
2808                 cmd[0] = WRITE_FILEMARKS;
2809                 if (cmd_in == MTWSM)
2810                         cmd[1] = 2;
2811                 if (cmd_in == MTWEOFI ||
2812                     (cmd_in == MTWEOF && STp->immediate_filemark))
2813                         cmd[1] |= 1;
2814                 cmd[2] = (arg >> 16);
2815                 cmd[3] = (arg >> 8);
2816                 cmd[4] = arg;
2817                 timeout = STp->device->request_queue->rq_timeout;
2818                 DEBC(
2819                         if (cmd_in != MTWSM)
2820                                 st_printk(ST_DEB_MSG, STp,
2821                                           "Writing %d filemarks.\n",
2822                                           cmd[2] * 65536 +
2823                                           cmd[3] * 256 +
2824                                           cmd[4]);
2825                         else
2826                                 st_printk(ST_DEB_MSG, STp,
2827                                           "Writing %d setmarks.\n",
2828                                           cmd[2] * 65536 +
2829                                           cmd[3] * 256 +
2830                                           cmd[4]);
2831                 )
2832                 if (fileno >= 0)
2833                         fileno += arg;
2834                 blkno = 0;
2835                 at_sm = (cmd_in == MTWSM);
2836                 break;
2837         case MTREW:
2838                 cmd[0] = REZERO_UNIT;
2839                 if (STp->immediate) {
2840                         cmd[1] = 1;     /* Don't wait for completion */
2841                         timeout = STp->device->request_queue->rq_timeout;
2842                 }
2843                 DEBC_printk(STp, "Rewinding tape.\n");
2844                 fileno = blkno = at_sm = 0;
2845                 break;
2846         case MTNOP:
2847                 DEBC_printk(STp, "No op on tape.\n");
2848                 return 0;       /* Should do something ? */
2849                 break;
2850         case MTRETEN:
2851                 cmd[0] = START_STOP;
2852                 if (STp->immediate) {
2853                         cmd[1] = 1;     /* Don't wait for completion */
2854                         timeout = STp->device->request_queue->rq_timeout;
2855                 }
2856                 cmd[4] = 3;
2857                 DEBC_printk(STp, "Retensioning tape.\n");
2858                 fileno = blkno = at_sm = 0;
2859                 break;
2860         case MTEOM:
2861                 if (!STp->fast_mteom) {
2862                         /* space to the end of tape */
2863                         ioctl_result = st_int_ioctl(STp, MTFSF, 0x7fffff);
2864                         fileno = STps->drv_file;
2865                         if (STps->eof >= ST_EOD_1)
2866                                 return 0;
2867                         /* The next lines would hide the number of spaced FileMarks
2868                            That's why I inserted the previous lines. I had no luck
2869                            with detecting EOM with FSF, so we go now to EOM.
2870                            Joerg Weule */
2871                 } else
2872                         fileno = (-1);
2873                 cmd[0] = SPACE;
2874                 cmd[1] = 3;
2875                 DEBC_printk(STp, "Spacing to end of recorded medium.\n");
2876                 blkno = -1;
2877                 at_sm = 0;
2878                 break;
2879         case MTERASE:
2880                 if (STp->write_prot)
2881                         return (-EACCES);
2882                 cmd[0] = ERASE;
2883                 cmd[1] = (arg ? 1 : 0); /* Long erase with non-zero argument */
2884                 if (STp->immediate) {
2885                         cmd[1] |= 2;    /* Don't wait for completion */
2886                         timeout = STp->device->request_queue->rq_timeout;
2887                 }
2888                 else
2889                         timeout = STp->long_timeout * 8;
2890
2891                 DEBC_printk(STp, "Erasing tape.\n");
2892                 fileno = blkno = at_sm = 0;
2893                 break;
2894         case MTSETBLK:          /* Set block length */
2895         case MTSETDENSITY:      /* Set tape density */
2896         case MTSETDRVBUFFER:    /* Set drive buffering */
2897         case SET_DENS_AND_BLK:  /* Set density and block size */
2898                 chg_eof = 0;
2899                 if (STp->dirty || (STp->buffer)->buffer_bytes != 0)
2900                         return (-EIO);  /* Not allowed if data in buffer */
2901                 if ((cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) &&
2902                     (arg & MT_ST_BLKSIZE_MASK) != 0 &&
2903                     STp->max_block > 0 &&
2904                     ((arg & MT_ST_BLKSIZE_MASK) < STp->min_block ||
2905                      (arg & MT_ST_BLKSIZE_MASK) > STp->max_block)) {
2906                         st_printk(KERN_WARNING, STp, "Illegal block size.\n");
2907                         return (-EINVAL);
2908                 }
2909                 cmd[0] = MODE_SELECT;
2910                 if ((STp->use_pf & USE_PF))
2911                         cmd[1] = MODE_SELECT_PAGE_FORMAT;
2912                 cmd[4] = datalen = 12;
2913                 direction = DMA_TO_DEVICE;
2914
2915                 memset((STp->buffer)->b_data, 0, 12);
2916                 if (cmd_in == MTSETDRVBUFFER)
2917                         (STp->buffer)->b_data[2] = (arg & 7) << 4;
2918                 else
2919                         (STp->buffer)->b_data[2] =
2920                             STp->drv_buffer << 4;
2921                 (STp->buffer)->b_data[3] = 8;   /* block descriptor length */
2922                 if (cmd_in == MTSETDENSITY) {
2923                         (STp->buffer)->b_data[4] = arg;
2924                         STp->density_changed = 1;       /* At least we tried ;-) */
2925                 } else if (cmd_in == SET_DENS_AND_BLK)
2926                         (STp->buffer)->b_data[4] = arg >> 24;
2927                 else
2928                         (STp->buffer)->b_data[4] = STp->density;
2929                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2930                         ltmp = arg & MT_ST_BLKSIZE_MASK;
2931                         if (cmd_in == MTSETBLK)
2932                                 STp->blksize_changed = 1; /* At least we tried ;-) */
2933                 } else
2934                         ltmp = STp->block_size;
2935                 (STp->buffer)->b_data[9] = (ltmp >> 16);
2936                 (STp->buffer)->b_data[10] = (ltmp >> 8);
2937                 (STp->buffer)->b_data[11] = ltmp;
2938                 timeout = STp->device->request_queue->rq_timeout;
2939                 DEBC(
2940                         if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK)
2941                                 st_printk(ST_DEB_MSG, STp,
2942                                           "Setting block size to %d bytes.\n",
2943                                           (STp->buffer)->b_data[9] * 65536 +
2944                                           (STp->buffer)->b_data[10] * 256 +
2945                                           (STp->buffer)->b_data[11]);
2946                         if (cmd_in == MTSETDENSITY || cmd_in == SET_DENS_AND_BLK)
2947                                 st_printk(ST_DEB_MSG, STp,
2948                                           "Setting density code to %x.\n",
2949                                           (STp->buffer)->b_data[4]);
2950                         if (cmd_in == MTSETDRVBUFFER)
2951                                 st_printk(ST_DEB_MSG, STp,
2952                                           "Setting drive buffer code to %d.\n",
2953                                           ((STp->buffer)->b_data[2] >> 4) & 7);
2954                 )
2955                 break;
2956         default:
2957                 return (-ENOSYS);
2958         }
2959
2960         SRpnt = st_do_scsi(NULL, STp, cmd, datalen, direction,
2961                            timeout, MAX_RETRIES, 1);
2962         if (!SRpnt)
2963                 return (STp->buffer)->syscall_result;
2964
2965         ioctl_result = (STp->buffer)->syscall_result;
2966
2967         if (!ioctl_result) {    /* SCSI command successful */
2968                 st_release_request(SRpnt);
2969                 SRpnt = NULL;
2970                 STps->drv_block = blkno;
2971                 STps->drv_file = fileno;
2972                 STps->at_sm = at_sm;
2973
2974                 if (cmd_in == MTBSFM)
2975                         ioctl_result = st_int_ioctl(STp, MTFSF, 1);
2976                 else if (cmd_in == MTFSFM)
2977                         ioctl_result = st_int_ioctl(STp, MTBSF, 1);
2978
2979                 if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
2980                         STp->block_size = arg & MT_ST_BLKSIZE_MASK;
2981                         if (STp->block_size != 0) {
2982                                 (STp->buffer)->buffer_blocks =
2983                                     (STp->buffer)->buffer_size / STp->block_size;
2984                         }
2985                         (STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
2986                         if (cmd_in == SET_DENS_AND_BLK)
2987                                 STp->density = arg >> MT_ST_DENSITY_SHIFT;
2988                 } else if (cmd_in == MTSETDRVBUFFER)
2989                         STp->drv_buffer = (arg & 7);
2990                 else if (cmd_in == MTSETDENSITY)
2991                         STp->density = arg;
2992
2993                 if (cmd_in == MTEOM)
2994                         STps->eof = ST_EOD;
2995                 else if (cmd_in == MTFSF)
2996                         STps->eof = ST_FM;
2997                 else if (chg_eof)
2998                         STps->eof = ST_NOEOF;
2999
3000                 if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
3001                         STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
3002         } else { /* SCSI command was not completely successful. Don't return
3003                     from this block without releasing the SCSI command block! */
3004                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
3005
3006                 if (cmdstatp->flags & SENSE_EOM) {
3007                         if (cmd_in != MTBSF && cmd_in != MTBSFM &&
3008                             cmd_in != MTBSR && cmd_in != MTBSS)
3009                                 STps->eof = ST_EOM_OK;
3010                         STps->drv_block = 0;
3011                 }
3012
3013                 if (cmdstatp->remainder_valid)
3014                         undone = (int)cmdstatp->uremainder64;
3015                 else
3016                         undone = 0;
3017
3018                 if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
3019                     cmdstatp->have_sense &&
3020                     (cmdstatp->flags & SENSE_EOM)) {
3021                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
3022                             cmdstatp->sense_hdr.sense_key == RECOVERED_ERROR) {
3023                                 ioctl_result = 0;       /* EOF(s) written successfully at EOM */
3024                                 STps->eof = ST_NOEOF;
3025                         } else {  /* Writing EOF(s) failed */
3026                                 if (fileno >= 0)
3027                                         fileno -= undone;
3028                                 if (undone < arg)
3029                                         STps->eof = ST_NOEOF;
3030                         }
3031                         STps->drv_file = fileno;
3032                 } else if ((cmd_in == MTFSF) || (cmd_in == MTFSFM)) {
3033                         if (fileno >= 0)
3034                                 STps->drv_file = fileno - undone;
3035                         else
3036                                 STps->drv_file = fileno;
3037                         STps->drv_block = -1;
3038                         STps->eof = ST_NOEOF;
3039                 } else if ((cmd_in == MTBSF) || (cmd_in == MTBSFM)) {
3040                         if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3041                                 undone = (-undone);
3042                         if (STps->drv_file >= 0)
3043                                 STps->drv_file = fileno + undone;
3044                         STps->drv_block = 0;
3045                         STps->eof = ST_NOEOF;
3046                 } else if (cmd_in == MTFSR) {
3047                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3048                                 if (STps->drv_file >= 0)
3049                                         STps->drv_file++;
3050                                 STps->drv_block = 0;
3051                                 STps->eof = ST_FM;
3052                         } else {
3053                                 if (blkno >= undone)
3054                                         STps->drv_block = blkno - undone;
3055                                 else
3056                                         STps->drv_block = (-1);
3057                                 STps->eof = ST_NOEOF;
3058                         }
3059                 } else if (cmd_in == MTBSR) {
3060                         if (cmdstatp->flags & SENSE_FMK) {      /* Hit filemark */
3061                                 STps->drv_file--;
3062                                 STps->drv_block = (-1);
3063                         } else {
3064                                 if (arg > 0 && undone < 0)  /* Some drives get this wrong */
3065                                         undone = (-undone);
3066                                 if (STps->drv_block >= 0)
3067                                         STps->drv_block = blkno + undone;
3068                         }
3069                         STps->eof = ST_NOEOF;
3070                 } else if (cmd_in == MTEOM) {
3071                         STps->drv_file = (-1);
3072                         STps->drv_block = (-1);
3073                         STps->eof = ST_EOD;
3074                 } else if (cmd_in == MTSETBLK ||
3075                            cmd_in == MTSETDENSITY ||
3076                            cmd_in == MTSETDRVBUFFER ||
3077                            cmd_in == SET_DENS_AND_BLK) {
3078                         if (cmdstatp->sense_hdr.sense_key == ILLEGAL_REQUEST &&
3079                             !(STp->use_pf & PF_TESTED)) {
3080                                 /* Try the other possible state of Page Format if not
3081                                    already tried */
3082                                 STp->use_pf = (STp->use_pf ^ USE_PF) | PF_TESTED;
3083                                 st_release_request(SRpnt);
3084                                 SRpnt = NULL;
3085                                 return st_int_ioctl(STp, cmd_in, arg);
3086                         }
3087                 } else if (chg_eof)
3088                         STps->eof = ST_NOEOF;
3089
3090                 if (cmdstatp->sense_hdr.sense_key == BLANK_CHECK)
3091                         STps->eof = ST_EOD;
3092
3093                 st_release_request(SRpnt);
3094                 SRpnt = NULL;
3095         }
3096
3097         return ioctl_result;
3098 }
3099 \f
3100
3101 /* Get the tape position. If bt == 2, arg points into a kernel space mt_loc
3102    structure. */
3103
3104 static int get_location(struct scsi_tape *STp, unsigned int *block, int *partition,
3105                         int logical)
3106 {
3107         int result;
3108         unsigned char scmd[MAX_COMMAND_SIZE];
3109         struct st_request *SRpnt;
3110
3111         if (STp->ready != ST_READY)
3112                 return (-EIO);
3113
3114         memset(scmd, 0, MAX_COMMAND_SIZE);
3115         if ((STp->device)->scsi_level < SCSI_2) {
3116                 scmd[0] = QFA_REQUEST_BLOCK;
3117                 scmd[4] = 3;
3118         } else {
3119                 scmd[0] = READ_POSITION;
3120                 if (!logical && !STp->scsi2_logical)
3121                         scmd[1] = 1;
3122         }
3123         SRpnt = st_do_scsi(NULL, STp, scmd, 20, DMA_FROM_DEVICE,
3124                            STp->device->request_queue->rq_timeout,
3125                            MAX_READY_RETRIES, 1);
3126         if (!SRpnt)
3127                 return (STp->buffer)->syscall_result;
3128
3129         if ((STp->buffer)->syscall_result != 0 ||
3130             (STp->device->scsi_level >= SCSI_2 &&
3131              ((STp->buffer)->b_data[0] & 4) != 0)) {
3132                 *block = *partition = 0;
3133                 DEBC_printk(STp, " Can't read tape position.\n");
3134                 result = (-EIO);
3135         } else {
3136                 result = 0;
3137                 if ((STp->device)->scsi_level < SCSI_2) {
3138                         *block = ((STp->buffer)->b_data[0] << 16)
3139                             + ((STp->buffer)->b_data[1] << 8)
3140                             + (STp->buffer)->b_data[2];
3141                         *partition = 0;
3142                 } else {
3143                         *block = ((STp->buffer)->b_data[4] << 24)
3144                             + ((STp->buffer)->b_data[5] << 16)
3145                             + ((STp->buffer)->b_data[6] << 8)
3146                             + (STp->buffer)->b_data[7];
3147                         *partition = (STp->buffer)->b_data[1];
3148                         if (((STp->buffer)->b_data[0] & 0x80) &&
3149                             (STp->buffer)->b_data[1] == 0)      /* BOP of partition 0 */
3150                                 STp->ps[0].drv_block = STp->ps[0].drv_file = 0;
3151                 }
3152                 DEBC_printk(STp, "Got tape pos. blk %d part %d.\n",
3153                             *block, *partition);
3154         }
3155         st_release_request(SRpnt);
3156         SRpnt = NULL;
3157
3158         return result;
3159 }
3160
3161
3162 /* Set the tape block and partition. Negative partition means that only the
3163    block should be set in vendor specific way. */
3164 static int set_location(struct scsi_tape *STp, unsigned int block, int partition,
3165                         int logical)
3166 {
3167         struct st_partstat *STps;
3168         int result, p;
3169         unsigned int blk;
3170         int timeout;
3171         unsigned char scmd[MAX_COMMAND_SIZE];
3172         struct st_request *SRpnt;
3173
3174         if (STp->ready != ST_READY)
3175                 return (-EIO);
3176         timeout = STp->long_timeout;
3177         STps = &(STp->ps[STp->partition]);
3178
3179         DEBC_printk(STp, "Setting block to %d and partition to %d.\n",
3180                     block, partition);
3181         DEB(if (partition < 0)
3182                 return (-EIO); )
3183
3184         /* Update the location at the partition we are leaving */
3185         if ((!STp->can_partitions && partition != 0) ||
3186             partition >= ST_NBR_PARTITIONS)
3187                 return (-EINVAL);
3188         if (partition != STp->partition) {
3189                 if (get_location(STp, &blk, &p, 1))
3190                         STps->last_block_valid = 0;
3191                 else {
3192                         STps->last_block_valid = 1;
3193                         STps->last_block_visited = blk;
3194                         DEBC_printk(STp, "Visited block %d for "
3195                                     "partition %d saved.\n",
3196                                     blk, STp->partition);
3197                 }
3198         }
3199
3200         memset(scmd, 0, MAX_COMMAND_SIZE);
3201         if ((STp->device)->scsi_level < SCSI_2) {
3202                 scmd[0] = QFA_SEEK_BLOCK;
3203                 scmd[2] = (block >> 16);
3204                 scmd[3] = (block >> 8);
3205                 scmd[4] = block;
3206                 scmd[5] = 0;
3207         } else {
3208                 scmd[0] = SEEK_10;
3209                 scmd[3] = (block >> 24);
3210                 scmd[4] = (block >> 16);
3211                 scmd[5] = (block >> 8);
3212                 scmd[6] = block;
3213                 if (!logical && !STp->scsi2_logical)
3214                         scmd[1] = 4;
3215                 if (STp->partition != partition) {
3216                         scmd[1] |= 2;
3217                         scmd[8] = partition;
3218                         DEBC_printk(STp, "Trying to change partition "
3219                                     "from %d to %d\n", STp->partition,
3220                                     partition);
3221                 }
3222         }
3223         if (STp->immediate) {
3224                 scmd[1] |= 1;           /* Don't wait for completion */
3225                 timeout = STp->device->request_queue->rq_timeout;
3226         }
3227
3228         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3229                            timeout, MAX_READY_RETRIES, 1);
3230         if (!SRpnt)
3231                 return (STp->buffer)->syscall_result;
3232
3233         STps->drv_block = STps->drv_file = (-1);
3234         STps->eof = ST_NOEOF;
3235         if ((STp->buffer)->syscall_result != 0) {
3236                 result = (-EIO);
3237                 if (STp->can_partitions &&
3238                     (STp->device)->scsi_level >= SCSI_2 &&
3239                     (p = find_partition(STp)) >= 0)
3240                         STp->partition = p;
3241         } else {
3242                 if (STp->can_partitions) {
3243                         STp->partition = partition;
3244                         STps = &(STp->ps[partition]);
3245                         if (!STps->last_block_valid ||
3246                             STps->last_block_visited != block) {
3247                                 STps->at_sm = 0;
3248                                 STps->rw = ST_IDLE;
3249                         }
3250                 } else
3251                         STps->at_sm = 0;
3252                 if (block == 0)
3253                         STps->drv_block = STps->drv_file = 0;
3254                 result = 0;
3255         }
3256
3257         st_release_request(SRpnt);
3258         SRpnt = NULL;
3259
3260         return result;
3261 }
3262
3263
3264 /* Find the current partition number for the drive status. Called from open and
3265    returns either partition number of negative error code. */
3266 static int find_partition(struct scsi_tape *STp)
3267 {
3268         int i, partition;
3269         unsigned int block;
3270
3271         if ((i = get_location(STp, &block, &partition, 1)) < 0)
3272                 return i;
3273         if (partition >= ST_NBR_PARTITIONS)
3274                 return (-EIO);
3275         return partition;
3276 }
3277
3278
3279 /* Change the partition if necessary */
3280 static int switch_partition(struct scsi_tape *STp)
3281 {
3282         struct st_partstat *STps;
3283
3284         if (STp->partition == STp->new_partition)
3285                 return 0;
3286         STps = &(STp->ps[STp->new_partition]);
3287         if (!STps->last_block_valid)
3288                 STps->last_block_visited = 0;
3289         return set_location(STp, STps->last_block_visited, STp->new_partition, 1);
3290 }
3291 \f
3292 /* Functions for reading and writing the medium partition mode page. */
3293
3294 #define PART_PAGE   0x11
3295 #define PART_PAGE_FIXED_LENGTH 8
3296
3297 #define PP_OFF_MAX_ADD_PARTS   2
3298 #define PP_OFF_NBR_ADD_PARTS   3
3299 #define PP_OFF_FLAGS           4
3300 #define PP_OFF_PART_UNITS      6
3301 #define PP_OFF_RESERVED        7
3302
3303 #define PP_BIT_IDP             0x20
3304 #define PP_BIT_FDP             0x80
3305 #define PP_MSK_PSUM_MB         0x10
3306 #define PP_MSK_PSUM_UNITS      0x18
3307 #define PP_MSK_POFM            0x04
3308
3309 /* Get the number of partitions on the tape. As a side effect reads the
3310    mode page into the tape buffer. */
3311 static int nbr_partitions(struct scsi_tape *STp)
3312 {
3313         int result;
3314
3315         if (STp->ready != ST_READY)
3316                 return (-EIO);
3317
3318         result = read_mode_page(STp, PART_PAGE, 1);
3319
3320         if (result) {
3321                 DEBC_printk(STp, "Can't read medium partition page.\n");
3322                 result = (-EIO);
3323         } else {
3324                 result = (STp->buffer)->b_data[MODE_HEADER_LENGTH +
3325                                               PP_OFF_NBR_ADD_PARTS] + 1;
3326                 DEBC_printk(STp, "Number of partitions %d.\n", result);
3327         }
3328
3329         return result;
3330 }
3331
3332
3333 static int format_medium(struct scsi_tape *STp, int format)
3334 {
3335         int result = 0;
3336         int timeout = STp->long_timeout;
3337         unsigned char scmd[MAX_COMMAND_SIZE];
3338         struct st_request *SRpnt;
3339
3340         memset(scmd, 0, MAX_COMMAND_SIZE);
3341         scmd[0] = FORMAT_UNIT;
3342         scmd[2] = format;
3343         if (STp->immediate) {
3344                 scmd[1] |= 1;           /* Don't wait for completion */
3345                 timeout = STp->device->request_queue->rq_timeout;
3346         }
3347         DEBC_printk(STp, "Sending FORMAT MEDIUM\n");
3348         SRpnt = st_do_scsi(NULL, STp, scmd, 0, DMA_NONE,
3349                            timeout, MAX_RETRIES, 1);
3350         if (!SRpnt)
3351                 result = STp->buffer->syscall_result;
3352         return result;
3353 }
3354
3355
3356 /* Partition the tape into two partitions if size > 0 or one partition if
3357    size == 0.
3358
3359    The block descriptors are read and written because Sony SDT-7000 does not
3360    work without this (suggestion from Michael Schaefer <Michael.Schaefer@dlr.de>).
3361
3362    My HP C1533A drive returns only one partition size field. This is used to
3363    set the size of partition 1. There is no size field for the default partition.
3364    Michael Schaefer's Sony SDT-7000 returns two descriptors and the second is
3365    used to set the size of partition 1 (this is what the SCSI-3 standard specifies).
3366    The following algorithm is used to accommodate both drives: if the number of
3367    partition size fields is greater than the maximum number of additional partitions
3368    in the mode page, the second field is used. Otherwise the first field is used.
3369
3370    For Seagate DDS drives the page length must be 8 when no partitions is defined
3371    and 10 when 1 partition is defined (information from Eric Lee Green). This is
3372    is acceptable also to some other old drives and enforced if the first partition
3373    size field is used for the first additional partition size.
3374
3375    For drives that advertize SCSI-3 or newer, use the SSC-3 methods.
3376  */
3377 static int partition_tape(struct scsi_tape *STp, int size)
3378 {
3379         int result;
3380         int target_partition;
3381         bool scsi3 = STp->device->scsi_level >= SCSI_3, needs_format = false;
3382         int pgo, psd_cnt, psdo;
3383         int psum = PP_MSK_PSUM_MB, units = 0;
3384         unsigned char *bp;
3385
3386         result = read_mode_page(STp, PART_PAGE, 0);
3387         if (result) {
3388                 DEBC_printk(STp, "Can't read partition mode page.\n");
3389                 return result;
3390         }
3391         target_partition = 1;
3392         if (size < 0) {
3393                 target_partition = 0;
3394                 size = -size;
3395         }
3396
3397         /* The mode page is in the buffer. Let's modify it and write it. */
3398         bp = (STp->buffer)->b_data;
3399         pgo = MODE_HEADER_LENGTH + bp[MH_OFF_BDESCS_LENGTH];
3400         DEBC_printk(STp, "Partition page length is %d bytes.\n",
3401                     bp[pgo + MP_OFF_PAGE_LENGTH] + 2);
3402
3403         psd_cnt = (bp[pgo + MP_OFF_PAGE_LENGTH] + 2 - PART_PAGE_FIXED_LENGTH) / 2;
3404
3405         if (scsi3) {
3406                 needs_format = (bp[pgo + PP_OFF_FLAGS] & PP_MSK_POFM) != 0;
3407                 if (needs_format && size == 0) {
3408                         /* No need to write the mode page when clearing
3409                          *  partitioning
3410                          */
3411                         DEBC_printk(STp, "Formatting tape with one partition.\n");
3412                         result = format_medium(STp, 0);
3413                         goto out;
3414                 }
3415                 if (needs_format)  /* Leave the old value for HP DATs claiming SCSI_3 */
3416                         psd_cnt = 2;
3417                 if ((bp[pgo + PP_OFF_FLAGS] & PP_MSK_PSUM_UNITS) == PP_MSK_PSUM_UNITS) {
3418                         /* Use units scaling for large partitions if the device
3419                          * suggests it and no precision lost. Required for IBM
3420                          * TS1140/50 drives that don't support MB units.
3421                          */
3422                         if (size >= 1000 && (size % 1000) == 0) {
3423                                 size /= 1000;
3424                                 psum = PP_MSK_PSUM_UNITS;
3425                                 units = 9; /* GB */
3426                         }
3427                 }
3428                 /* Try it anyway if too large to specify in MB */
3429                 if (psum == PP_MSK_PSUM_MB && size >= 65534) {
3430                         size /= 1000;
3431                         psum = PP_MSK_PSUM_UNITS;
3432                         units = 9;  /* GB */
3433                 }
3434         }
3435
3436         if (size >= 65535 ||  /* Does not fit into two bytes */
3437             (target_partition == 0 && psd_cnt < 2)) {
3438                 result = -EINVAL;
3439                 goto out;
3440         }
3441
3442         psdo = pgo + PART_PAGE_FIXED_LENGTH;
3443         /* The second condition is for HP DDS which use only one partition size
3444          * descriptor
3445          */
3446         if (target_partition > 0 &&
3447             (psd_cnt > bp[pgo + PP_OFF_MAX_ADD_PARTS] ||
3448              bp[pgo + PP_OFF_MAX_ADD_PARTS] != 1)) {
3449                 bp[psdo] = bp[psdo + 1] = 0xff;  /* Rest to partition 0 */
3450                 psdo += 2;
3451         }
3452         memset(bp + psdo, 0, bp[pgo + PP_OFF_NBR_ADD_PARTS] * 2);
3453
3454         DEBC_printk(STp, "psd_cnt %d, max.parts %d, nbr_parts %d\n",
3455                     psd_cnt, bp[pgo + PP_OFF_MAX_ADD_PARTS],
3456                     bp[pgo + PP_OFF_NBR_ADD_PARTS]);
3457
3458         if (size == 0) {
3459                 bp[pgo + PP_OFF_NBR_ADD_PARTS] = 0;
3460                 if (psd_cnt <= bp[pgo + PP_OFF_MAX_ADD_PARTS])
3461                     bp[pgo + MP_OFF_PAGE_LENGTH] = 6;
3462                 DEBC_printk(STp, "Formatting tape with one partition.\n");
3463         } else {
3464                 bp[psdo] = (size >> 8) & 0xff;
3465                 bp[psdo + 1] = size & 0xff;
3466                 if (target_partition == 0)
3467                         bp[psdo + 2] = bp[psdo + 3] = 0xff;
3468                 bp[pgo + 3] = 1;
3469                 if (bp[pgo + MP_OFF_PAGE_LENGTH] < 8)
3470                     bp[pgo + MP_OFF_PAGE_LENGTH] = 8;
3471                 DEBC_printk(STp,
3472                             "Formatting tape with two partitions (%i = %d MB).\n",
3473                             target_partition, units > 0 ? size * 1000 : size);
3474         }
3475         bp[pgo + PP_OFF_PART_UNITS] = 0;
3476         bp[pgo + PP_OFF_RESERVED] = 0;
3477         if (size != 1 || units != 0) {
3478                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_IDP | psum |
3479                         (bp[pgo + PP_OFF_FLAGS] & 0x07);
3480                 bp[pgo + PP_OFF_PART_UNITS] = units;
3481         } else
3482                 bp[pgo + PP_OFF_FLAGS] = PP_BIT_FDP |
3483                         (bp[pgo + PP_OFF_FLAGS] & 0x1f);
3484         bp[pgo + MP_OFF_PAGE_LENGTH] = 6 + psd_cnt * 2;
3485
3486         result = write_mode_page(STp, PART_PAGE, 1);
3487
3488         if (!result && needs_format)
3489                 result = format_medium(STp, 1);
3490
3491         if (result) {
3492                 st_printk(KERN_INFO, STp, "Partitioning of tape failed.\n");
3493                 result = (-EIO);
3494         }
3495
3496 out:
3497         return result;
3498 }
3499 \f
3500
3501
3502 /* The ioctl command */
3503 static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
3504 {
3505         int i, cmd_nr, cmd_type, bt;
3506         int retval = 0;
3507         unsigned int blk;
3508         struct scsi_tape *STp = file->private_data;
3509         struct st_modedef *STm;
3510         struct st_partstat *STps;
3511         void __user *p = (void __user *)arg;
3512
3513         if (mutex_lock_interruptible(&STp->lock))
3514                 return -ERESTARTSYS;
3515
3516         DEB(
3517         if (debugging && !STp->in_use) {
3518                 st_printk(ST_DEB_MSG, STp, "Incorrect device.\n");
3519                 retval = (-EIO);
3520                 goto out;
3521         } ) /* end DEB */
3522
3523         STm = &(STp->modes[STp->current_mode]);
3524         STps = &(STp->ps[STp->partition]);
3525
3526         /*
3527          * If we are in the middle of error recovery, don't let anyone
3528          * else try and use this device.  Also, if error recovery fails, it
3529          * may try and take the device offline, in which case all further
3530          * access to the device is prohibited.
3531          */
3532         retval = scsi_ioctl_block_when_processing_errors(STp->device, cmd_in,
3533                         file->f_flags & O_NDELAY);
3534         if (retval)
3535                 goto out;
3536
3537         cmd_type = _IOC_TYPE(cmd_in);
3538         cmd_nr = _IOC_NR(cmd_in);
3539
3540         if (cmd_type == _IOC_TYPE(MTIOCTOP) && cmd_nr == _IOC_NR(MTIOCTOP)) {
3541                 struct mtop mtc;
3542
3543                 if (_IOC_SIZE(cmd_in) != sizeof(mtc)) {
3544                         retval = (-EINVAL);
3545                         goto out;
3546                 }
3547
3548                 i = copy_from_user(&mtc, p, sizeof(struct mtop));
3549                 if (i) {
3550                         retval = (-EFAULT);
3551                         goto out;
3552                 }
3553
3554                 if (mtc.mt_op == MTSETDRVBUFFER && !capable(CAP_SYS_ADMIN)) {
3555                         st_printk(KERN_WARNING, STp,
3556                                   "MTSETDRVBUFFER only allowed for root.\n");
3557                         retval = (-EPERM);
3558                         goto out;
3559                 }
3560                 if (!STm->defined &&
3561                     (mtc.mt_op != MTSETDRVBUFFER &&
3562                      (mtc.mt_count & MT_ST_OPTIONS) == 0)) {
3563                         retval = (-ENXIO);
3564                         goto out;
3565                 }
3566
3567                 if (!STp->pos_unknown) {
3568
3569                         if (STps->eof == ST_FM_HIT) {
3570                                 if (mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3571                                     mtc.mt_op == MTEOM) {
3572                                         mtc.mt_count -= 1;
3573                                         if (STps->drv_file >= 0)
3574                                                 STps->drv_file += 1;
3575                                 } else if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM) {
3576                                         mtc.mt_count += 1;
3577                                         if (STps->drv_file >= 0)
3578                                                 STps->drv_file += 1;
3579                                 }
3580                         }
3581
3582                         if (mtc.mt_op == MTSEEK) {
3583                                 /* Old position must be restored if partition will be
3584                                    changed */
3585                                 i = !STp->can_partitions ||
3586                                     (STp->new_partition != STp->partition);
3587                         } else {
3588                                 i = mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3589                                     mtc.mt_op == MTRETEN || mtc.mt_op == MTEOM ||
3590                                     mtc.mt_op == MTLOCK || mtc.mt_op == MTLOAD ||
3591                                     mtc.mt_op == MTFSF || mtc.mt_op == MTFSFM ||
3592                                     mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM ||
3593                                     mtc.mt_op == MTCOMPRESSION;
3594                         }
3595                         i = flush_buffer(STp, i);
3596                         if (i < 0) {
3597                                 retval = i;
3598                                 goto out;
3599                         }
3600                         if (STps->rw == ST_WRITING &&
3601                             (mtc.mt_op == MTREW || mtc.mt_op == MTOFFL ||
3602                              mtc.mt_op == MTSEEK ||
3603                              mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)) {
3604                                 i = st_int_ioctl(STp, MTWEOF, 1);
3605                                 if (i < 0) {
3606                                         retval = i;
3607                                         goto out;
3608                                 }
3609                                 if (mtc.mt_op == MTBSF || mtc.mt_op == MTBSFM)
3610                                         mtc.mt_count++;
3611                                 STps->rw = ST_IDLE;
3612                              }
3613
3614                 } else {
3615                         /*
3616                          * If there was a bus reset, block further access
3617                          * to this device.  If the user wants to rewind the tape,
3618                          * then reset the flag and allow access again.
3619                          */
3620                         if (mtc.mt_op != MTREW &&
3621                             mtc.mt_op != MTOFFL &&
3622                             mtc.mt_op != MTRETEN &&
3623                             mtc.mt_op != MTERASE &&
3624                             mtc.mt_op != MTSEEK &&
3625                             mtc.mt_op != MTEOM) {
3626                                 retval = (-EIO);
3627                                 goto out;
3628                         }
3629                         reset_state(STp);
3630                         /* remove this when the midlevel properly clears was_reset */
3631                         STp->device->was_reset = 0;
3632                 }
3633
3634                 if (mtc.mt_op != MTNOP && mtc.mt_op != MTSETBLK &&
3635                     mtc.mt_op != MTSETDENSITY && mtc.mt_op != MTWSM &&
3636                     mtc.mt_op != MTSETDRVBUFFER && mtc.mt_op != MTSETPART)
3637                         STps->rw = ST_IDLE;     /* Prevent automatic WEOF and fsf */
3638
3639                 if (mtc.mt_op == MTOFFL && STp->door_locked != ST_UNLOCKED)
3640                         do_door_lock(STp, 0);   /* Ignore result! */
3641
3642                 if (mtc.mt_op == MTSETDRVBUFFER &&
3643                     (mtc.mt_count & MT_ST_OPTIONS) != 0) {
3644                         retval = st_set_options(STp, mtc.mt_count);
3645                         goto out;
3646                 }
3647
3648                 if (mtc.mt_op == MTSETPART) {
3649                         if (!STp->can_partitions ||
3650                             mtc.mt_count < 0 || mtc.mt_count >= ST_NBR_PARTITIONS) {
3651                                 retval = (-EINVAL);
3652                                 goto out;
3653                         }
3654                         if (mtc.mt_count >= STp->nbr_partitions &&
3655                             (STp->nbr_partitions = nbr_partitions(STp)) < 0) {
3656                                 retval = (-EIO);
3657                                 goto out;
3658                         }
3659                         if (mtc.mt_count >= STp->nbr_partitions) {
3660                                 retval = (-EINVAL);
3661                                 goto out;
3662                         }
3663                         STp->new_partition = mtc.mt_count;
3664                         retval = 0;
3665                         goto out;
3666                 }
3667
3668                 if (mtc.mt_op == MTMKPART) {
3669                         if (!STp->can_partitions) {
3670                                 retval = (-EINVAL);
3671                                 goto out;
3672                         }
3673                         i = do_load_unload(STp, file, 1);
3674                         if (i < 0) {
3675                                 retval = i;
3676                                 goto out;
3677                         }
3678                         i = partition_tape(STp, mtc.mt_count);
3679                         if (i < 0) {
3680                                 retval = i;
3681                                 goto out;
3682                         }
3683                         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
3684                                 STp->ps[i].rw = ST_IDLE;
3685                                 STp->ps[i].at_sm = 0;
3686                                 STp->ps[i].last_block_valid = 0;
3687                         }
3688                         STp->partition = STp->new_partition = 0;
3689                         STp->nbr_partitions = mtc.mt_count != 0 ? 2 : 1;
3690                         STps->drv_block = STps->drv_file = 0;
3691                         retval = 0;
3692                         goto out;
3693                 }
3694
3695                 if (mtc.mt_op == MTSEEK) {
3696                         i = set_location(STp, mtc.mt_count, STp->new_partition, 0);
3697                         if (!STp->can_partitions)
3698                                 STp->ps[0].rw = ST_IDLE;
3699                         retval = i;
3700                         goto out;
3701                 }
3702
3703                 if (mtc.mt_op == MTUNLOAD || mtc.mt_op == MTOFFL) {
3704                         retval = do_load_unload(STp, file, 0);
3705                         goto out;
3706                 }
3707
3708                 if (mtc.mt_op == MTLOAD) {
3709                         retval = do_load_unload(STp, file, max(1, mtc.mt_count));
3710                         goto out;
3711                 }
3712
3713                 if (mtc.mt_op == MTLOCK || mtc.mt_op == MTUNLOCK) {
3714                         retval = do_door_lock(STp, (mtc.mt_op == MTLOCK));
3715                         goto out;
3716                 }
3717
3718                 if (STp->can_partitions && STp->ready == ST_READY &&
3719                     (i = switch_partition(STp)) < 0) {
3720                         retval = i;
3721                         goto out;
3722                 }
3723
3724                 if (mtc.mt_op == MTCOMPRESSION)
3725                         retval = st_compression(STp, (mtc.mt_count & 1));
3726                 else
3727                         retval = st_int_ioctl(STp, mtc.mt_op, mtc.mt_count);
3728                 goto out;
3729         }
3730         if (!STm->defined) {
3731                 retval = (-ENXIO);
3732                 goto out;
3733         }
3734
3735         if ((i = flush_buffer(STp, 0)) < 0) {
3736                 retval = i;
3737                 goto out;
3738         }
3739         if (STp->can_partitions &&
3740             (i = switch_partition(STp)) < 0) {
3741                 retval = i;
3742                 goto out;
3743         }
3744
3745         if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
3746                 struct mtget mt_status;
3747
3748                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {
3749                          retval = (-EINVAL);
3750                          goto out;
3751                 }
3752
3753                 mt_status.mt_type = STp->tape_type;
3754                 mt_status.mt_dsreg =
3755                     ((STp->block_size << MT_ST_BLKSIZE_SHIFT) & MT_ST_BLKSIZE_MASK) |
3756                     ((STp->density << MT_ST_DENSITY_SHIFT) & MT_ST_DENSITY_MASK);
3757                 mt_status.mt_blkno = STps->drv_block;
3758                 mt_status.mt_fileno = STps->drv_file;
3759                 if (STp->block_size != 0) {
3760                         if (STps->rw == ST_WRITING)
3761                                 mt_status.mt_blkno +=
3762                                     (STp->buffer)->buffer_bytes / STp->block_size;
3763                         else if (STps->rw == ST_READING)
3764                                 mt_status.mt_blkno -=
3765                                         ((STp->buffer)->buffer_bytes +
3766                                          STp->block_size - 1) / STp->block_size;
3767                 }
3768
3769                 mt_status.mt_gstat = 0;
3770                 if (STp->drv_write_prot)
3771                         mt_status.mt_gstat |= GMT_WR_PROT(0xffffffff);
3772                 if (mt_status.mt_blkno == 0) {
3773                         if (mt_status.mt_fileno == 0)
3774                                 mt_status.mt_gstat |= GMT_BOT(0xffffffff);
3775                         else
3776                                 mt_status.mt_gstat |= GMT_EOF(0xffffffff);
3777                 }
3778                 mt_status.mt_erreg = (STp->recover_reg << MT_ST_SOFTERR_SHIFT);
3779                 mt_status.mt_resid = STp->partition;
3780                 if (STps->eof == ST_EOM_OK || STps->eof == ST_EOM_ERROR)
3781                         mt_status.mt_gstat |= GMT_EOT(0xffffffff);
3782                 else if (STps->eof >= ST_EOM_OK)
3783                         mt_status.mt_gstat |= GMT_EOD(0xffffffff);
3784                 if (STp->density == 1)
3785                         mt_status.mt_gstat |= GMT_D_800(0xffffffff);
3786                 else if (STp->density == 2)
3787                         mt_status.mt_gstat |= GMT_D_1600(0xffffffff);
3788                 else if (STp->density == 3)
3789                         mt_status.mt_gstat |= GMT_D_6250(0xffffffff);
3790                 if (STp->ready == ST_READY)
3791                         mt_status.mt_gstat |= GMT_ONLINE(0xffffffff);
3792                 if (STp->ready == ST_NO_TAPE)
3793                         mt_status.mt_gstat |= GMT_DR_OPEN(0xffffffff);
3794                 if (STps->at_sm)
3795                         mt_status.mt_gstat |= GMT_SM(0xffffffff);
3796                 if (STm->do_async_writes ||
3797                     (STm->do_buffer_writes && STp->block_size != 0) ||
3798                     STp->drv_buffer != 0)
3799                         mt_status.mt_gstat |= GMT_IM_REP_EN(0xffffffff);
3800                 if (STp->cleaning_req)
3801                         mt_status.mt_gstat |= GMT_CLN(0xffffffff);
3802
3803                 i = copy_to_user(p, &mt_status, sizeof(struct mtget));
3804                 if (i) {
3805                         retval = (-EFAULT);
3806                         goto out;
3807                 }
3808
3809                 STp->recover_reg = 0;           /* Clear after read */
3810                 retval = 0;
3811                 goto out;
3812         }                       /* End of MTIOCGET */
3813         if (cmd_type == _IOC_TYPE(MTIOCPOS) && cmd_nr == _IOC_NR(MTIOCPOS)) {
3814                 struct mtpos mt_pos;
3815                 if (_IOC_SIZE(cmd_in) != sizeof(struct mtpos)) {
3816                          retval = (-EINVAL);
3817                          goto out;
3818                 }
3819                 if ((i = get_location(STp, &blk, &bt, 0)) < 0) {
3820                         retval = i;
3821                         goto out;
3822                 }
3823                 mt_pos.mt_blkno = blk;
3824                 i = copy_to_user(p, &mt_pos, sizeof(struct mtpos));
3825                 if (i)
3826                         retval = (-EFAULT);
3827                 goto out;
3828         }
3829         mutex_unlock(&STp->lock);
3830         switch (cmd_in) {
3831                 case SCSI_IOCTL_GET_IDLUN:
3832                 case SCSI_IOCTL_GET_BUS_NUMBER:
3833                         break;
3834                 default:
3835                         if ((cmd_in == SG_IO ||
3836                              cmd_in == SCSI_IOCTL_SEND_COMMAND ||
3837                              cmd_in == CDROM_SEND_PACKET) &&
3838                             !capable(CAP_SYS_RAWIO))
3839                                 i = -EPERM;
3840                         else
3841                                 i = scsi_cmd_ioctl(STp->disk->queue, STp->disk,
3842                                                    file->f_mode, cmd_in, p);
3843                         if (i != -ENOTTY)
3844                                 return i;
3845                         break;
3846         }
3847         retval = scsi_ioctl(STp->device, cmd_in, p);
3848         if (!retval && cmd_in == SCSI_IOCTL_STOP_UNIT) { /* unload */
3849                 STp->rew_at_close = 0;
3850                 STp->ready = ST_NO_TAPE;
3851         }
3852         return retval;
3853
3854  out:
3855         mutex_unlock(&STp->lock);
3856         return retval;
3857 }
3858
3859 #ifdef CONFIG_COMPAT
3860 static long st_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
3861 {
3862         struct scsi_tape *STp = file->private_data;
3863         struct scsi_device *sdev = STp->device;
3864         int ret = -ENOIOCTLCMD;
3865         if (sdev->host->hostt->compat_ioctl) {
3866
3867                 ret = sdev->host->hostt->compat_ioctl(sdev, cmd, (void __user *)arg);
3868
3869         }
3870         return ret;
3871 }
3872 #endif
3873
3874 \f
3875
3876 /* Try to allocate a new tape buffer. Calling function must not hold
3877    dev_arr_lock. */
3878 static struct st_buffer *new_tape_buffer(int need_dma, int max_sg)
3879 {
3880         struct st_buffer *tb;
3881
3882         tb = kzalloc(sizeof(struct st_buffer), GFP_ATOMIC);
3883         if (!tb) {
3884                 printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
3885                 return NULL;
3886         }
3887         tb->frp_segs = 0;
3888         tb->use_sg = max_sg;
3889         tb->dma = need_dma;
3890         tb->buffer_size = 0;
3891
3892         tb->reserved_pages = kzalloc(max_sg * sizeof(struct page *),
3893                                      GFP_ATOMIC);
3894         if (!tb->reserved_pages) {
3895                 kfree(tb);
3896                 return NULL;
3897         }
3898
3899         return tb;
3900 }
3901
3902
3903 /* Try to allocate enough space in the tape buffer */
3904 #define ST_MAX_ORDER 6
3905
3906 static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dma)
3907 {
3908         int segs, max_segs, b_size, order, got;
3909         gfp_t priority;
3910
3911         if (new_size <= STbuffer->buffer_size)
3912                 return 1;
3913
3914         if (STbuffer->buffer_size <= PAGE_SIZE)
3915                 normalize_buffer(STbuffer);  /* Avoid extra segment */
3916
3917         max_segs = STbuffer->use_sg;
3918
3919         priority = GFP_KERNEL | __GFP_NOWARN;
3920         if (need_dma)
3921                 priority |= GFP_DMA;
3922
3923         if (STbuffer->cleared)
3924                 priority |= __GFP_ZERO;
3925
3926         if (STbuffer->frp_segs) {
3927                 order = STbuffer->reserved_page_order;
3928                 b_size = PAGE_SIZE << order;
3929         } else {
3930                 for (b_size = PAGE_SIZE, order = 0;
3931                      order < ST_MAX_ORDER &&
3932                              max_segs * (PAGE_SIZE << order) < new_size;
3933                      order++, b_size *= 2)
3934                         ;  /* empty */
3935                 STbuffer->reserved_page_order = order;
3936         }
3937         if (max_segs * (PAGE_SIZE << order) < new_size) {
3938                 if (order == ST_MAX_ORDER)
3939                         return 0;
3940                 normalize_buffer(STbuffer);
3941                 return enlarge_buffer(STbuffer, new_size, need_dma);
3942         }
3943
3944         for (segs = STbuffer->frp_segs, got = STbuffer->buffer_size;
3945              segs < max_segs && got < new_size;) {
3946                 struct page *page;
3947
3948                 page = alloc_pages(priority, order);
3949                 if (!page) {
3950                         DEB(STbuffer->buffer_size = got);
3951                         normalize_buffer(STbuffer);
3952                         return 0;
3953                 }
3954
3955                 STbuffer->frp_segs += 1;
3956                 got += b_size;
3957                 STbuffer->buffer_size = got;
3958                 STbuffer->reserved_pages[segs] = page;
3959                 segs++;
3960         }
3961         STbuffer->b_data = page_address(STbuffer->reserved_pages[0]);
3962
3963         return 1;
3964 }
3965
3966
3967 /* Make sure that no data from previous user is in the internal buffer */
3968 static void clear_buffer(struct st_buffer * st_bp)
3969 {
3970         int i;
3971
3972         for (i=0; i < st_bp->frp_segs; i++)
3973                 memset(page_address(st_bp->reserved_pages[i]), 0,
3974                        PAGE_SIZE << st_bp->reserved_page_order);
3975         st_bp->cleared = 1;
3976 }
3977
3978
3979 /* Release the extra buffer */
3980 static void normalize_buffer(struct st_buffer * STbuffer)
3981 {
3982         int i, order = STbuffer->reserved_page_order;
3983
3984         for (i = 0; i < STbuffer->frp_segs; i++) {
3985                 __free_pages(STbuffer->reserved_pages[i], order);
3986                 STbuffer->buffer_size -= (PAGE_SIZE << order);
3987         }
3988         STbuffer->frp_segs = 0;
3989         STbuffer->sg_segs = 0;
3990         STbuffer->reserved_page_order = 0;
3991         STbuffer->map_data.offset = 0;
3992 }
3993
3994
3995 /* Move data from the user buffer to the tape buffer. Returns zero (success) or
3996    negative error code. */
3997 static int append_to_buffer(const char __user *ubp, struct st_buffer * st_bp, int do_count)
3998 {
3999         int i, cnt, res, offset;
4000         int length = PAGE_SIZE << st_bp->reserved_page_order;
4001
4002         for (i = 0, offset = st_bp->buffer_bytes;
4003              i < st_bp->frp_segs && offset >= length; i++)
4004                 offset -= length;
4005         if (i == st_bp->frp_segs) {     /* Should never happen */
4006                 printk(KERN_WARNING "st: append_to_buffer offset overflow.\n");
4007                 return (-EIO);
4008         }
4009         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4010                 struct page *page = st_bp->reserved_pages[i];
4011                 cnt = length - offset < do_count ? length - offset : do_count;
4012                 res = copy_from_user(page_address(page) + offset, ubp, cnt);
4013                 if (res)
4014                         return (-EFAULT);
4015                 do_count -= cnt;
4016                 st_bp->buffer_bytes += cnt;
4017                 ubp += cnt;
4018                 offset = 0;
4019         }
4020         if (do_count) /* Should never happen */
4021                 return (-EIO);
4022
4023         return 0;
4024 }
4025
4026
4027 /* Move data from the tape buffer to the user buffer. Returns zero (success) or
4028    negative error code. */
4029 static int from_buffer(struct st_buffer * st_bp, char __user *ubp, int do_count)
4030 {
4031         int i, cnt, res, offset;
4032         int length = PAGE_SIZE << st_bp->reserved_page_order;
4033
4034         for (i = 0, offset = st_bp->read_pointer;
4035              i < st_bp->frp_segs && offset >= length; i++)
4036                 offset -= length;
4037         if (i == st_bp->frp_segs) {     /* Should never happen */
4038                 printk(KERN_WARNING "st: from_buffer offset overflow.\n");
4039                 return (-EIO);
4040         }
4041         for (; i < st_bp->frp_segs && do_count > 0; i++) {
4042                 struct page *page = st_bp->reserved_pages[i];
4043                 cnt = length - offset < do_count ? length - offset : do_count;
4044                 res = copy_to_user(ubp, page_address(page) + offset, cnt);
4045                 if (res)
4046                         return (-EFAULT);
4047                 do_count -= cnt;
4048                 st_bp->buffer_bytes -= cnt;
4049                 st_bp->read_pointer += cnt;
4050                 ubp += cnt;
4051                 offset = 0;
4052         }
4053         if (do_count) /* Should never happen */
4054                 return (-EIO);
4055
4056         return 0;
4057 }
4058
4059
4060 /* Move data towards start of buffer */
4061 static void move_buffer_data(struct st_buffer * st_bp, int offset)
4062 {
4063         int src_seg, dst_seg, src_offset = 0, dst_offset;
4064         int count, total;
4065         int length = PAGE_SIZE << st_bp->reserved_page_order;
4066
4067         if (offset == 0)
4068                 return;
4069
4070         total=st_bp->buffer_bytes - offset;
4071         for (src_seg=0; src_seg < st_bp->frp_segs; src_seg++) {
4072                 src_offset = offset;
4073                 if (src_offset < length)
4074                         break;
4075                 offset -= length;
4076         }
4077
4078         st_bp->buffer_bytes = st_bp->read_pointer = total;
4079         for (dst_seg=dst_offset=0; total > 0; ) {
4080                 struct page *dpage = st_bp->reserved_pages[dst_seg];
4081                 struct page *spage = st_bp->reserved_pages[src_seg];
4082
4083                 count = min(length - dst_offset, length - src_offset);
4084                 memmove(page_address(dpage) + dst_offset,
4085                         page_address(spage) + src_offset, count);
4086                 src_offset += count;
4087                 if (src_offset >= length) {
4088                         src_seg++;
4089                         src_offset = 0;
4090                 }
4091                 dst_offset += count;
4092                 if (dst_offset >= length) {
4093                         dst_seg++;
4094                         dst_offset = 0;
4095                 }
4096                 total -= count;
4097         }
4098 }
4099
4100 /* Validate the options from command line or module parameters */
4101 static void validate_options(void)
4102 {
4103         if (buffer_kbs > 0)
4104                 st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
4105         if (max_sg_segs >= ST_FIRST_SG)
4106                 st_max_sg_segs = max_sg_segs;
4107 }
4108
4109 #ifndef MODULE
4110 /* Set the boot options. Syntax is defined in Documenation/scsi/st.txt.
4111  */
4112 static int __init st_setup(char *str)
4113 {
4114         int i, len, ints[5];
4115         char *stp;
4116
4117         stp = get_options(str, ARRAY_SIZE(ints), ints);
4118
4119         if (ints[0] > 0) {
4120                 for (i = 0; i < ints[0] && i < ARRAY_SIZE(parms); i++)
4121                         if (parms[i].val)
4122                                 *parms[i].val = ints[i + 1];
4123         } else {
4124                 while (stp != NULL) {
4125                         for (i = 0; i < ARRAY_SIZE(parms); i++) {
4126                                 len = strlen(parms[i].name);
4127                                 if (!strncmp(stp, parms[i].name, len) &&
4128                                     (*(stp + len) == ':' || *(stp + len) == '=')) {
4129                                         if (parms[i].val)
4130                                                 *parms[i].val =
4131                                                         simple_strtoul(stp + len + 1, NULL, 0);
4132                                         else
4133                                                 printk(KERN_WARNING "st: Obsolete parameter %s\n",
4134                                                        parms[i].name);
4135                                         break;
4136                                 }
4137                         }
4138                         if (i >= ARRAY_SIZE(parms))
4139                                  printk(KERN_WARNING "st: invalid parameter in '%s'\n",
4140                                         stp);
4141                         stp = strchr(stp, ',');
4142                         if (stp)
4143                                 stp++;
4144                 }
4145         }
4146
4147         validate_options();
4148
4149         return 1;
4150 }
4151
4152 __setup("st=", st_setup);
4153
4154 #endif
4155
4156 static const struct file_operations st_fops =
4157 {
4158         .owner =        THIS_MODULE,
4159         .read =         st_read,
4160         .write =        st_write,
4161         .unlocked_ioctl = st_ioctl,
4162 #ifdef CONFIG_COMPAT
4163         .compat_ioctl = st_compat_ioctl,
4164 #endif
4165         .open =         st_open,
4166         .flush =        st_flush,
4167         .release =      st_release,
4168         .llseek =       noop_llseek,
4169 };
4170
4171 static int create_one_cdev(struct scsi_tape *tape, int mode, int rew)
4172 {
4173         int i, error;
4174         dev_t cdev_devno;
4175         struct cdev *cdev;
4176         struct device *dev;
4177         struct st_modedef *STm = &(tape->modes[mode]);
4178         char name[10];
4179         int dev_num = tape->index;
4180
4181         cdev_devno = MKDEV(SCSI_TAPE_MAJOR, TAPE_MINOR(dev_num, mode, rew));
4182
4183         cdev = cdev_alloc();
4184         if (!cdev) {
4185                 pr_err("st%d: out of memory. Device not attached.\n", dev_num);
4186                 error = -ENOMEM;
4187                 goto out;
4188         }
4189         cdev->owner = THIS_MODULE;
4190         cdev->ops = &st_fops;
4191         STm->cdevs[rew] = cdev;
4192
4193         error = cdev_add(cdev, cdev_devno, 1);
4194         if (error) {
4195                 pr_err("st%d: Can't add %s-rewind mode %d\n", dev_num,
4196                        rew ? "non" : "auto", mode);
4197                 pr_err("st%d: Device not attached.\n", dev_num);
4198                 goto out_free;
4199         }
4200
4201         i = mode << (4 - ST_NBR_MODE_BITS);
4202         snprintf(name, 10, "%s%s%s", rew ? "n" : "",
4203                  tape->disk->disk_name, st_formats[i]);
4204
4205         dev = device_create(&st_sysfs_class, &tape->device->sdev_gendev,
4206                             cdev_devno, &tape->modes[mode], "%s", name);
4207         if (IS_ERR(dev)) {
4208                 pr_err("st%d: device_create failed\n", dev_num);
4209                 error = PTR_ERR(dev);
4210                 goto out_free;
4211         }
4212
4213         STm->devs[rew] = dev;
4214
4215         return 0;
4216 out_free:
4217         cdev_del(STm->cdevs[rew]);
4218 out:
4219         STm->cdevs[rew] = NULL;
4220         STm->devs[rew] = NULL;
4221         return error;
4222 }
4223
4224 static int create_cdevs(struct scsi_tape *tape)
4225 {
4226         int mode, error;
4227         for (mode = 0; mode < ST_NBR_MODES; ++mode) {
4228                 error = create_one_cdev(tape, mode, 0);
4229                 if (error)
4230                         return error;
4231                 error = create_one_cdev(tape, mode, 1);
4232                 if (error)
4233                         return error;
4234         }
4235
4236         return sysfs_create_link(&tape->device->sdev_gendev.kobj,
4237                                  &tape->modes[0].devs[0]->kobj, "tape");
4238 }
4239
4240 static void remove_cdevs(struct scsi_tape *tape)
4241 {
4242         int mode, rew;
4243         sysfs_remove_link(&tape->device->sdev_gendev.kobj, "tape");
4244         for (mode = 0; mode < ST_NBR_MODES; mode++) {
4245                 struct st_modedef *STm = &(tape->modes[mode]);
4246                 for (rew = 0; rew < 2; rew++) {
4247                         if (STm->cdevs[rew])
4248                                 cdev_del(STm->cdevs[rew]);
4249                         if (STm->devs[rew])
4250                                 device_unregister(STm->devs[rew]);
4251                 }
4252         }
4253 }
4254
4255 static int st_probe(struct device *dev)
4256 {
4257         struct scsi_device *SDp = to_scsi_device(dev);
4258         struct gendisk *disk = NULL;
4259         struct scsi_tape *tpnt = NULL;
4260         struct st_modedef *STm;
4261         struct st_partstat *STps;
4262         struct st_buffer *buffer;
4263         int i, error;
4264         char *stp;
4265
4266         if (SDp->type != TYPE_TAPE)
4267                 return -ENODEV;
4268         if ((stp = st_incompatible(SDp))) {
4269                 sdev_printk(KERN_INFO, SDp, "Found incompatible tape\n");
4270                 sdev_printk(KERN_INFO, SDp,
4271                             "st: The suggested driver is %s.\n", stp);
4272                 return -ENODEV;
4273         }
4274
4275         scsi_autopm_get_device(SDp);
4276         i = queue_max_segments(SDp->request_queue);
4277         if (st_max_sg_segs < i)
4278                 i = st_max_sg_segs;
4279         buffer = new_tape_buffer((SDp->host)->unchecked_isa_dma, i);
4280         if (buffer == NULL) {
4281                 sdev_printk(KERN_ERR, SDp,
4282                             "st: Can't allocate new tape buffer. "
4283                             "Device not attached.\n");
4284                 goto out;
4285         }
4286
4287         disk = alloc_disk(1);
4288         if (!disk) {
4289                 sdev_printk(KERN_ERR, SDp,
4290                             "st: out of memory. Device not attached.\n");
4291                 goto out_buffer_free;
4292         }
4293
4294         tpnt = kzalloc(sizeof(struct scsi_tape), GFP_ATOMIC);
4295         if (tpnt == NULL) {
4296                 sdev_printk(KERN_ERR, SDp,
4297                             "st: Can't allocate device descriptor.\n");
4298                 goto out_put_disk;
4299         }
4300         kref_init(&tpnt->kref);
4301         tpnt->disk = disk;
4302         disk->private_data = &tpnt->driver;
4303         disk->queue = SDp->request_queue;
4304         /* SCSI tape doesn't register this gendisk via add_disk().  Manually
4305          * take queue reference that release_disk() expects. */
4306         if (!blk_get_queue(disk->queue))
4307                 goto out_put_disk;
4308         tpnt->driver = &st_template;
4309
4310         tpnt->device = SDp;
4311         if (SDp->scsi_level <= 2)
4312                 tpnt->tape_type = MT_ISSCSI1;
4313         else
4314                 tpnt->tape_type = MT_ISSCSI2;
4315
4316         tpnt->buffer = buffer;
4317         tpnt->buffer->last_SRpnt = NULL;
4318
4319         tpnt->inited = 0;
4320         tpnt->dirty = 0;
4321         tpnt->in_use = 0;
4322         tpnt->drv_buffer = 1;   /* Try buffering if no mode sense */
4323         tpnt->restr_dma = (SDp->host)->unchecked_isa_dma;
4324         tpnt->use_pf = (SDp->scsi_level >= SCSI_2);
4325         tpnt->density = 0;
4326         tpnt->do_auto_lock = ST_AUTO_LOCK;
4327         tpnt->can_bsr = (SDp->scsi_level > 2 ? 1 : ST_IN_FILE_POS); /* BSR mandatory in SCSI3 */
4328         tpnt->can_partitions = 0;
4329         tpnt->two_fm = ST_TWO_FM;
4330         tpnt->fast_mteom = ST_FAST_MTEOM;
4331         tpnt->scsi2_logical = ST_SCSI2LOGICAL;
4332         tpnt->sili = ST_SILI;
4333         tpnt->immediate = ST_NOWAIT;
4334         tpnt->immediate_filemark = 0;
4335         tpnt->default_drvbuffer = 0xff;         /* No forced buffering */
4336         tpnt->partition = 0;
4337         tpnt->new_partition = 0;
4338         tpnt->nbr_partitions = 0;
4339         blk_queue_rq_timeout(tpnt->device->request_queue, ST_TIMEOUT);
4340         tpnt->long_timeout = ST_LONG_TIMEOUT;
4341         tpnt->try_dio = try_direct_io && !SDp->host->unchecked_isa_dma;
4342
4343         for (i = 0; i < ST_NBR_MODES; i++) {
4344                 STm = &(tpnt->modes[i]);
4345                 STm->defined = 0;
4346                 STm->sysv = ST_SYSV;
4347                 STm->defaults_for_writes = 0;
4348                 STm->do_async_writes = ST_ASYNC_WRITES;
4349                 STm->do_buffer_writes = ST_BUFFER_WRITES;
4350                 STm->do_read_ahead = ST_READ_AHEAD;
4351                 STm->default_compression = ST_DONT_TOUCH;
4352                 STm->default_blksize = (-1);    /* No forced size */
4353                 STm->default_density = (-1);    /* No forced density */
4354                 STm->tape = tpnt;
4355         }
4356
4357         for (i = 0; i < ST_NBR_PARTITIONS; i++) {
4358                 STps = &(tpnt->ps[i]);
4359                 STps->rw = ST_IDLE;
4360                 STps->eof = ST_NOEOF;
4361                 STps->at_sm = 0;
4362                 STps->last_block_valid = 0;
4363                 STps->drv_block = (-1);
4364                 STps->drv_file = (-1);
4365         }
4366
4367         tpnt->current_mode = 0;
4368         tpnt->modes[0].defined = 1;
4369
4370         tpnt->density_changed = tpnt->compression_changed =
4371             tpnt->blksize_changed = 0;
4372         mutex_init(&tpnt->lock);
4373
4374         idr_preload(GFP_KERNEL);
4375         spin_lock(&st_index_lock);
4376         error = idr_alloc(&st_index_idr, tpnt, 0, ST_MAX_TAPES + 1, GFP_NOWAIT);
4377         spin_unlock(&st_index_lock);
4378         idr_preload_end();
4379         if (error < 0) {
4380                 pr_warn("st: idr allocation failed: %d\n", error);
4381                 goto out_put_queue;
4382         }
4383         tpnt->index = error;
4384         sprintf(disk->disk_name, "st%d", tpnt->index);
4385         tpnt->stats = kzalloc(sizeof(struct scsi_tape_stats), GFP_KERNEL);
4386         if (tpnt->stats == NULL) {
4387                 sdev_printk(KERN_ERR, SDp,
4388                             "st: Can't allocate statistics.\n");
4389                 goto out_idr_remove;
4390         }
4391
4392         dev_set_drvdata(dev, tpnt);
4393
4394
4395         error = create_cdevs(tpnt);
4396         if (error)
4397                 goto out_remove_devs;
4398         scsi_autopm_put_device(SDp);
4399
4400         sdev_printk(KERN_NOTICE, SDp,
4401                     "Attached scsi tape %s\n", tape_name(tpnt));
4402         sdev_printk(KERN_INFO, SDp, "%s: try direct i/o: %s (alignment %d B)\n",
4403                     tape_name(tpnt), tpnt->try_dio ? "yes" : "no",
4404                     queue_dma_alignment(SDp->request_queue) + 1);
4405
4406         return 0;
4407
4408 out_remove_devs:
4409         remove_cdevs(tpnt);
4410         kfree(tpnt->stats);
4411 out_idr_remove:
4412         spin_lock(&st_index_lock);
4413         idr_remove(&st_index_idr, tpnt->index);
4414         spin_unlock(&st_index_lock);
4415 out_put_queue:
4416         blk_put_queue(disk->queue);
4417 out_put_disk:
4418         put_disk(disk);
4419         kfree(tpnt);
4420 out_buffer_free:
4421         kfree(buffer);
4422 out:
4423         scsi_autopm_put_device(SDp);
4424         return -ENODEV;
4425 };
4426
4427
4428 static int st_remove(struct device *dev)
4429 {
4430         struct scsi_tape *tpnt = dev_get_drvdata(dev);
4431         int index = tpnt->index;
4432
4433         scsi_autopm_get_device(to_scsi_device(dev));
4434         remove_cdevs(tpnt);
4435
4436         mutex_lock(&st_ref_mutex);
4437         kref_put(&tpnt->kref, scsi_tape_release);
4438         mutex_unlock(&st_ref_mutex);
4439         spin_lock(&st_index_lock);
4440         idr_remove(&st_index_idr, index);
4441         spin_unlock(&st_index_lock);
4442         return 0;
4443 }
4444
4445 /**
4446  *      scsi_tape_release - Called to free the Scsi_Tape structure
4447  *      @kref: pointer to embedded kref
4448  *
4449  *      st_ref_mutex must be held entering this routine.  Because it is
4450  *      called on last put, you should always use the scsi_tape_get()
4451  *      scsi_tape_put() helpers which manipulate the semaphore directly
4452  *      and never do a direct kref_put().
4453  **/
4454 static void scsi_tape_release(struct kref *kref)
4455 {
4456         struct scsi_tape *tpnt = to_scsi_tape(kref);
4457         struct gendisk *disk = tpnt->disk;
4458
4459         tpnt->device = NULL;
4460
4461         if (tpnt->buffer) {
4462                 normalize_buffer(tpnt->buffer);
4463                 kfree(tpnt->buffer->reserved_pages);
4464                 kfree(tpnt->buffer);
4465         }
4466
4467         disk->private_data = NULL;
4468         put_disk(disk);
4469         kfree(tpnt->stats);
4470         kfree(tpnt);
4471         return;
4472 }
4473
4474 static struct class st_sysfs_class = {
4475         .name = "scsi_tape",
4476         .dev_groups = st_dev_groups,
4477 };
4478
4479 static int __init init_st(void)
4480 {
4481         int err;
4482
4483         validate_options();
4484
4485         printk(KERN_INFO "st: Version %s, fixed bufsize %d, s/g segs %d\n",
4486                 verstr, st_fixed_buffer_size, st_max_sg_segs);
4487
4488         debugging = (debug_flag > 0) ? debug_flag : NO_DEBUG;
4489         if (debugging) {
4490                 printk(KERN_INFO "st: Debugging enabled debug_flag = %d\n",
4491                         debugging);
4492         }
4493
4494         err = class_register(&st_sysfs_class);
4495         if (err) {
4496                 pr_err("Unable register sysfs class for SCSI tapes\n");
4497                 return err;
4498         }
4499
4500         err = register_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4501                                      ST_MAX_TAPE_ENTRIES, "st");
4502         if (err) {
4503                 printk(KERN_ERR "Unable to get major %d for SCSI tapes\n",
4504                        SCSI_TAPE_MAJOR);
4505                 goto err_class;
4506         }
4507
4508         err = scsi_register_driver(&st_template.gendrv);
4509         if (err)
4510                 goto err_chrdev;
4511
4512         return 0;
4513
4514 err_chrdev:
4515         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4516                                  ST_MAX_TAPE_ENTRIES);
4517 err_class:
4518         class_unregister(&st_sysfs_class);
4519         return err;
4520 }
4521
4522 static void __exit exit_st(void)
4523 {
4524         scsi_unregister_driver(&st_template.gendrv);
4525         unregister_chrdev_region(MKDEV(SCSI_TAPE_MAJOR, 0),
4526                                  ST_MAX_TAPE_ENTRIES);
4527         class_unregister(&st_sysfs_class);
4528         idr_destroy(&st_index_idr);
4529         printk(KERN_INFO "st: Unloaded.\n");
4530 }
4531
4532 module_init(init_st);
4533 module_exit(exit_st);
4534
4535
4536 /* The sysfs driver interface. Read-only at the moment */
4537 static ssize_t try_direct_io_show(struct device_driver *ddp, char *buf)
4538 {
4539         return scnprintf(buf, PAGE_SIZE, "%d\n", try_direct_io);
4540 }
4541 static DRIVER_ATTR_RO(try_direct_io);
4542
4543 static ssize_t fixed_buffer_size_show(struct device_driver *ddp, char *buf)
4544 {
4545         return scnprintf(buf, PAGE_SIZE, "%d\n", st_fixed_buffer_size);
4546 }
4547 static DRIVER_ATTR_RO(fixed_buffer_size);
4548
4549 static ssize_t max_sg_segs_show(struct device_driver *ddp, char *buf)
4550 {
4551         return scnprintf(buf, PAGE_SIZE, "%d\n", st_max_sg_segs);
4552 }
4553 static DRIVER_ATTR_RO(max_sg_segs);
4554
4555 static ssize_t version_show(struct device_driver *ddd, char *buf)
4556 {
4557         return scnprintf(buf, PAGE_SIZE, "[%s]\n", verstr);
4558 }
4559 static DRIVER_ATTR_RO(version);
4560
4561 #if DEBUG
4562 static ssize_t debug_flag_store(struct device_driver *ddp,
4563         const char *buf, size_t count)
4564 {
4565 /* We only care what the first byte of the data is the rest is unused.
4566  * if it's a '1' we turn on debug and if it's a '0' we disable it. All
4567  * other values have -EINVAL returned if they are passed in.
4568  */
4569         if (count > 0) {
4570                 if (buf[0] == '0') {
4571                         debugging = NO_DEBUG;
4572                         return count;
4573                 } else if (buf[0] == '1') {
4574                         debugging = 1;
4575                         return count;
4576                 }
4577         }
4578         return -EINVAL;
4579 }
4580
4581 static ssize_t debug_flag_show(struct device_driver *ddp, char *buf)
4582 {
4583         return scnprintf(buf, PAGE_SIZE, "%d\n", debugging);
4584 }
4585 static DRIVER_ATTR_RW(debug_flag);
4586 #endif
4587
4588 static struct attribute *st_drv_attrs[] = {
4589         &driver_attr_try_direct_io.attr,
4590         &driver_attr_fixed_buffer_size.attr,
4591         &driver_attr_max_sg_segs.attr,
4592         &driver_attr_version.attr,
4593 #if DEBUG
4594         &driver_attr_debug_flag.attr,
4595 #endif
4596         NULL,
4597 };
4598 ATTRIBUTE_GROUPS(st_drv);
4599
4600 /* The sysfs simple class interface */
4601 static ssize_t
4602 defined_show(struct device *dev, struct device_attribute *attr, char *buf)
4603 {
4604         struct st_modedef *STm = dev_get_drvdata(dev);
4605         ssize_t l = 0;
4606
4607         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->defined);
4608         return l;
4609 }
4610 static DEVICE_ATTR_RO(defined);
4611
4612 static ssize_t
4613 default_blksize_show(struct device *dev, struct device_attribute *attr,
4614                      char *buf)
4615 {
4616         struct st_modedef *STm = dev_get_drvdata(dev);
4617         ssize_t l = 0;
4618
4619         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_blksize);
4620         return l;
4621 }
4622 static DEVICE_ATTR_RO(default_blksize);
4623
4624 static ssize_t
4625 default_density_show(struct device *dev, struct device_attribute *attr,
4626                      char *buf)
4627 {
4628         struct st_modedef *STm = dev_get_drvdata(dev);
4629         ssize_t l = 0;
4630         char *fmt;
4631
4632         fmt = STm->default_density >= 0 ? "0x%02x\n" : "%d\n";
4633         l = snprintf(buf, PAGE_SIZE, fmt, STm->default_density);
4634         return l;
4635 }
4636 static DEVICE_ATTR_RO(default_density);
4637
4638 static ssize_t
4639 default_compression_show(struct device *dev, struct device_attribute *attr,
4640                          char *buf)
4641 {
4642         struct st_modedef *STm = dev_get_drvdata(dev);
4643         ssize_t l = 0;
4644
4645         l = snprintf(buf, PAGE_SIZE, "%d\n", STm->default_compression - 1);
4646         return l;
4647 }
4648 static DEVICE_ATTR_RO(default_compression);
4649
4650 static ssize_t
4651 options_show(struct device *dev, struct device_attribute *attr, char *buf)
4652 {
4653         struct st_modedef *STm = dev_get_drvdata(dev);
4654         struct scsi_tape *STp = STm->tape;
4655         int options;
4656         ssize_t l = 0;
4657
4658         options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0;
4659         options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0;
4660         options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0;
4661         DEB( options |= debugging ? MT_ST_DEBUGGING : 0 );
4662         options |= STp->two_fm ? MT_ST_TWO_FM : 0;
4663         options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0;
4664         options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0;
4665         options |= STp->can_bsr ? MT_ST_CAN_BSR : 0;
4666         options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0;
4667         options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0;
4668         options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0;
4669         options |= STm->sysv ? MT_ST_SYSV : 0;
4670         options |= STp->immediate ? MT_ST_NOWAIT : 0;
4671         options |= STp->immediate_filemark ? MT_ST_NOWAIT_EOF : 0;
4672         options |= STp->sili ? MT_ST_SILI : 0;
4673
4674         l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options);
4675         return l;
4676 }
4677 static DEVICE_ATTR_RO(options);
4678
4679 /* Support for tape stats */
4680
4681 /**
4682  * read_cnt_show - return read count - count of reads made from tape drive
4683  * @dev: struct device
4684  * @attr: attribute structure
4685  * @buf: buffer to return formatted data in
4686  */
4687 static ssize_t read_cnt_show(struct device *dev,
4688         struct device_attribute *attr, char *buf)
4689 {
4690         struct st_modedef *STm = dev_get_drvdata(dev);
4691
4692         return sprintf(buf, "%lld",
4693                        (long long)atomic64_read(&STm->tape->stats->read_cnt));
4694 }
4695 static DEVICE_ATTR_RO(read_cnt);
4696
4697 /**
4698  * read_byte_cnt_show - return read byte count - tape drives
4699  * may use blocks less than 512 bytes this gives the raw byte count of
4700  * of data read from the tape drive.
4701  * @dev: struct device
4702  * @attr: attribute structure
4703  * @buf: buffer to return formatted data in
4704  */
4705 static ssize_t read_byte_cnt_show(struct device *dev,
4706         struct device_attribute *attr, char *buf)
4707 {
4708         struct st_modedef *STm = dev_get_drvdata(dev);
4709
4710         return sprintf(buf, "%lld",
4711                        (long long)atomic64_read(&STm->tape->stats->read_byte_cnt));
4712 }
4713 static DEVICE_ATTR_RO(read_byte_cnt);
4714
4715 /**
4716  * read_us_show - return read us - overall time spent waiting on reads in ns.
4717  * @dev: struct device
4718  * @attr: attribute structure
4719  * @buf: buffer to return formatted data in
4720  */
4721 static ssize_t read_ns_show(struct device *dev,
4722         struct device_attribute *attr, char *buf)
4723 {
4724         struct st_modedef *STm = dev_get_drvdata(dev);
4725
4726         return sprintf(buf, "%lld",
4727                        (long long)atomic64_read(&STm->tape->stats->tot_read_time));
4728 }
4729 static DEVICE_ATTR_RO(read_ns);
4730
4731 /**
4732  * write_cnt_show - write count - number of user calls
4733  * to write(2) that have written data to tape.
4734  * @dev: struct device
4735  * @attr: attribute structure
4736  * @buf: buffer to return formatted data in
4737  */
4738 static ssize_t write_cnt_show(struct device *dev,
4739         struct device_attribute *attr, char *buf)
4740 {
4741         struct st_modedef *STm = dev_get_drvdata(dev);
4742
4743         return sprintf(buf, "%lld",
4744                        (long long)atomic64_read(&STm->tape->stats->write_cnt));
4745 }
4746 static DEVICE_ATTR_RO(write_cnt);
4747
4748 /**
4749  * write_byte_cnt_show - write byte count - raw count of
4750  * bytes written to tape.
4751  * @dev: struct device
4752  * @attr: attribute structure
4753  * @buf: buffer to return formatted data in
4754  */
4755 static ssize_t write_byte_cnt_show(struct device *dev,
4756         struct device_attribute *attr, char *buf)
4757 {
4758         struct st_modedef *STm = dev_get_drvdata(dev);
4759
4760         return sprintf(buf, "%lld",
4761                        (long long)atomic64_read(&STm->tape->stats->write_byte_cnt));
4762 }
4763 static DEVICE_ATTR_RO(write_byte_cnt);
4764
4765 /**
4766  * write_ns_show - write ns - number of nanoseconds waiting on write
4767  * requests to complete.
4768  * @dev: struct device
4769  * @attr: attribute structure
4770  * @buf: buffer to return formatted data in
4771  */
4772 static ssize_t write_ns_show(struct device *dev,
4773         struct device_attribute *attr, char *buf)
4774 {
4775         struct st_modedef *STm = dev_get_drvdata(dev);
4776
4777         return sprintf(buf, "%lld",
4778                        (long long)atomic64_read(&STm->tape->stats->tot_write_time));
4779 }
4780 static DEVICE_ATTR_RO(write_ns);
4781
4782 /**
4783  * in_flight_show - number of I/Os currently in flight -
4784  * in most cases this will be either 0 or 1. It may be higher if someone
4785  * has also issued other SCSI commands such as via an ioctl.
4786  * @dev: struct device
4787  * @attr: attribute structure
4788  * @buf: buffer to return formatted data in
4789  */
4790 static ssize_t in_flight_show(struct device *dev,
4791         struct device_attribute *attr, char *buf)
4792 {
4793         struct st_modedef *STm = dev_get_drvdata(dev);
4794
4795         return sprintf(buf, "%lld",
4796                        (long long)atomic64_read(&STm->tape->stats->in_flight));
4797 }
4798 static DEVICE_ATTR_RO(in_flight);
4799
4800 /**
4801  * io_ns_show - io wait ns - this is the number of ns spent
4802  * waiting on all I/O to complete. This includes tape movement commands
4803  * such as rewinding, seeking to end of file or tape, it also includes
4804  * read and write. To determine the time spent on tape movement
4805  * subtract the read and write ns from this value.
4806  * @dev: struct device
4807  * @attr: attribute structure
4808  * @buf: buffer to return formatted data in
4809  */
4810 static ssize_t io_ns_show(struct device *dev,
4811         struct device_attribute *attr, char *buf)
4812 {
4813         struct st_modedef *STm = dev_get_drvdata(dev);
4814
4815         return sprintf(buf, "%lld",
4816                        (long long)atomic64_read(&STm->tape->stats->tot_io_time));
4817 }
4818 static DEVICE_ATTR_RO(io_ns);
4819
4820 /**
4821  * other_cnt_show - other io count - this is the number of
4822  * I/O requests other than read and write requests.
4823  * Typically these are tape movement requests but will include driver
4824  * tape movement. This includes only requests issued by the st driver.
4825  * @dev: struct device
4826  * @attr: attribute structure
4827  * @buf: buffer to return formatted data in
4828  */
4829 static ssize_t other_cnt_show(struct device *dev,
4830         struct device_attribute *attr, char *buf)
4831 {
4832         struct st_modedef *STm = dev_get_drvdata(dev);
4833
4834         return sprintf(buf, "%lld",
4835                        (long long)atomic64_read(&STm->tape->stats->other_cnt));
4836 }
4837 static DEVICE_ATTR_RO(other_cnt);
4838
4839 /**
4840  * resid_cnt_show - A count of the number of times we get a residual
4841  * count - this should indicate someone issuing reads larger than the
4842  * block size on tape.
4843  * @dev: struct device
4844  * @attr: attribute structure
4845  * @buf: buffer to return formatted data in
4846  */
4847 static ssize_t resid_cnt_show(struct device *dev,
4848         struct device_attribute *attr, char *buf)
4849 {
4850         struct st_modedef *STm = dev_get_drvdata(dev);
4851
4852         return sprintf(buf, "%lld",
4853                        (long long)atomic64_read(&STm->tape->stats->resid_cnt));
4854 }
4855 static DEVICE_ATTR_RO(resid_cnt);
4856
4857 static struct attribute *st_dev_attrs[] = {
4858         &dev_attr_defined.attr,
4859         &dev_attr_default_blksize.attr,
4860         &dev_attr_default_density.attr,
4861         &dev_attr_default_compression.attr,
4862         &dev_attr_options.attr,
4863         NULL,
4864 };
4865
4866 static struct attribute *st_stats_attrs[] = {
4867         &dev_attr_read_cnt.attr,
4868         &dev_attr_read_byte_cnt.attr,
4869         &dev_attr_read_ns.attr,
4870         &dev_attr_write_cnt.attr,
4871         &dev_attr_write_byte_cnt.attr,
4872         &dev_attr_write_ns.attr,
4873         &dev_attr_in_flight.attr,
4874         &dev_attr_io_ns.attr,
4875         &dev_attr_other_cnt.attr,
4876         &dev_attr_resid_cnt.attr,
4877         NULL,
4878 };
4879
4880 static struct attribute_group stats_group = {
4881         .name = "stats",
4882         .attrs = st_stats_attrs,
4883 };
4884
4885 static struct attribute_group st_group = {
4886         .attrs = st_dev_attrs,
4887 };
4888
4889 static const struct attribute_group *st_dev_groups[] = {
4890         &st_group,
4891         &stats_group,
4892         NULL,
4893 };
4894
4895 /* The following functions may be useful for a larger audience. */
4896 static int sgl_map_user_pages(struct st_buffer *STbp,
4897                               const unsigned int max_pages, unsigned long uaddr,
4898                               size_t count, int rw)
4899 {
4900         unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
4901         unsigned long start = uaddr >> PAGE_SHIFT;
4902         const int nr_pages = end - start;
4903         int res, i, j;
4904         struct page **pages;
4905         struct rq_map_data *mdata = &STbp->map_data;
4906
4907         /* User attempted Overflow! */
4908         if ((uaddr + count) < uaddr)
4909                 return -EINVAL;
4910
4911         /* Too big */
4912         if (nr_pages > max_pages)
4913                 return -ENOMEM;
4914
4915         /* Hmm? */
4916         if (count == 0)
4917                 return 0;
4918
4919         if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_KERNEL)) == NULL)
4920                 return -ENOMEM;
4921
4922         /* Try to fault in all of the necessary pages */
4923         /* rw==READ means read from drive, write into memory area */
4924         res = get_user_pages_unlocked(
4925                 uaddr,
4926                 nr_pages,
4927                 pages,
4928                 rw == READ ? FOLL_WRITE : 0); /* don't force */
4929
4930         /* Errors and no page mapped should return here */
4931         if (res < nr_pages)
4932                 goto out_unmap;
4933
4934         for (i=0; i < nr_pages; i++) {
4935                 /* FIXME: flush superflous for rw==READ,
4936                  * probably wrong function for rw==WRITE
4937                  */
4938                 flush_dcache_page(pages[i]);
4939         }
4940
4941         mdata->offset = uaddr & ~PAGE_MASK;
4942         STbp->mapped_pages = pages;
4943
4944         return nr_pages;
4945  out_unmap:
4946         if (res > 0) {
4947                 for (j=0; j < res; j++)
4948                         put_page(pages[j]);
4949                 res = 0;
4950         }
4951         kfree(pages);
4952         return res;
4953 }
4954
4955
4956 /* And unmap them... */
4957 static int sgl_unmap_user_pages(struct st_buffer *STbp,
4958                                 const unsigned int nr_pages, int dirtied)
4959 {
4960         int i;
4961
4962         for (i=0; i < nr_pages; i++) {
4963                 struct page *page = STbp->mapped_pages[i];
4964
4965                 if (dirtied)
4966                         SetPageDirty(page);
4967                 /* FIXME: cache flush missing for rw==READ
4968                  * FIXME: call the correct reference counting function
4969                  */
4970                 put_page(page);
4971         }
4972         kfree(STbp->mapped_pages);
4973         STbp->mapped_pages = NULL;
4974
4975         return 0;
4976 }