drivers/target/target_core_user.c

   1 /*
   2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
   3  * Copyright (C) 2014 Red Hat, Inc.
   4  * Copyright (C) 2015 Arrikto, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <linux/spinlock.h>
  21 #include <linux/module.h>
  22 #include <linux/idr.h>
  23 #include <linux/kernel.h>
  24 #include <linux/timer.h>
  25 #include <linux/parser.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/uio_driver.h>
  28 #include <linux/stringify.h>
  29 #include <linux/bitops.h>
  30 #include <linux/highmem.h>
  31 #include <net/genetlink.h>
  32 #include <scsi/scsi_common.h>
  33 #include <scsi/scsi_proto.h>
  34 #include <target/target_core_base.h>
  35 #include <target/target_core_fabric.h>
  36 #include <target/target_core_backend.h>
  37
  38 #include <linux/target_core_user.h>
  39
  40 /*
  41  * Define a shared-memory interface for LIO to pass SCSI commands and
  42  * data to userspace for processing. This is to allow backends that
  43  * are too complex for in-kernel support to be possible.
  44  *
  45  * It uses the UIO framework to do a lot of the device-creation and
  46  * introspection work for us.
  47  *
  48  * See the .h file for how the ring is laid out. Note that while the
  49  * command ring is defined, the particulars of the data area are
  50  * not. Offset values in the command entry point to other locations
  51  * internal to the mmap()ed area. There is separate space outside the
  52  * command ring for data buffers. This leaves maximum flexibility for
  53  * moving buffer allocations, or even page flipping or other
  54  * allocation techniques, without altering the command ring layout.
  55  *
  56  * SECURITY:
  57  * The user process must be assumed to be malicious. There's no way to
  58  * prevent it breaking the command ring protocol if it wants, but in
  59  * order to prevent other issues we must only ever read *data* from
  60  * the shared memory area, not offsets or sizes. This applies to
  61  * command ring entries as well as the mailbox. Extra code needed for
  62  * this may have a 'UAM' comment.
  63  */
  64
  65
  66 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
  67
  68 #define DATA_BLOCK_BITS 256
  69 #define DATA_BLOCK_SIZE 4096
  70
  71 #define CMDR_SIZE (16 * 4096)
  72 #define DATA_SIZE (DATA_BLOCK_BITS * DATA_BLOCK_SIZE)
  73
  74 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
  75
  76 static struct device *tcmu_root_device;
  77
  78 struct tcmu_hba {
  79         u32 host_id;
  80 };
  81
  82 #define TCMU_CONFIG_LEN 256
  83
  84 struct tcmu_dev {
  85         struct se_device se_dev;
  86
  87         char *name;
  88         struct se_hba *hba;
  89
  90 #define TCMU_DEV_BIT_OPEN 0
  91 #define TCMU_DEV_BIT_BROKEN 1
  92         unsigned long flags;
  93
  94         struct uio_info uio_info;
  95
  96         struct tcmu_mailbox *mb_addr;
  97         size_t dev_size;
  98         u32 cmdr_size;
  99         u32 cmdr_last_cleaned;
 100         /* Offset of data area from start of mb */
 101         /* Must add data_off and mb_addr to get the address */
 102         size_t data_off;
 103         size_t data_size;
 104
 105         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 106
 107         wait_queue_head_t wait_cmdr;
 108         /* TODO should this be a mutex? */
 109         spinlock_t cmdr_lock;
 110
 111         struct idr commands;
 112         spinlock_t commands_lock;
 113
 114         struct timer_list timeout;
 115
 116         char dev_config[TCMU_CONFIG_LEN];
 117 };
 118
 119 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
 120
 121 #define CMDR_OFF sizeof(struct tcmu_mailbox)
 122
 123 struct tcmu_cmd {
 124         struct se_cmd *se_cmd;
 125         struct tcmu_dev *tcmu_dev;
 126
 127         uint16_t cmd_id;
 128
 129         /* Can't use se_cmd when cleaning up expired cmds, because if
 130            cmd has been completed then accessing se_cmd is off limits */
 131         DECLARE_BITMAP(data_bitmap, DATA_BLOCK_BITS);
 132
 133         unsigned long deadline;
 134
 135 #define TCMU_CMD_BIT_EXPIRED 0
 136         unsigned long flags;
 137 };
 138
 139 static struct kmem_cache *tcmu_cmd_cache;
 140
 141 /* multicast group */
 142 enum tcmu_multicast_groups {
 143         TCMU_MCGRP_CONFIG,
 144 };
 145
 146 static const struct genl_multicast_group tcmu_mcgrps[] = {
 147         [TCMU_MCGRP_CONFIG] = { .name = "config", },
 148 };
 149
 150 /* Our generic netlink family */
 151 static struct genl_family tcmu_genl_family __ro_after_init = {
 152         .module = THIS_MODULE,
 153         .hdrsize = 0,
 154         .name = "TCM-USER",
 155         .version = 1,
 156         .maxattr = TCMU_ATTR_MAX,
 157         .mcgrps = tcmu_mcgrps,
 158         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
 159         .netnsok = true,
 160 };
 161
 162 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
 163 {
 164         struct se_device *se_dev = se_cmd->se_dev;
 165         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 166         struct tcmu_cmd *tcmu_cmd;
 167         int cmd_id;
 168
 169         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
 170         if (!tcmu_cmd)
 171                 return NULL;
 172
 173         tcmu_cmd->se_cmd = se_cmd;
 174         tcmu_cmd->tcmu_dev = udev;
 175         tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
 176
 177         idr_preload(GFP_KERNEL);
 178         spin_lock_irq(&udev->commands_lock);
 179         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
 180                 USHRT_MAX, GFP_NOWAIT);
 181         spin_unlock_irq(&udev->commands_lock);
 182         idr_preload_end();
 183
 184         if (cmd_id < 0) {
 185                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 186                 return NULL;
 187         }
 188         tcmu_cmd->cmd_id = cmd_id;
 189
 190         return tcmu_cmd;
 191 }
 192
 193 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
 194 {
 195         unsigned long offset = offset_in_page(vaddr);
 196
 197         size = round_up(size+offset, PAGE_SIZE);
 198         vaddr -= offset;
 199
 200         while (size) {
 201                 flush_dcache_page(virt_to_page(vaddr));
 202                 size -= PAGE_SIZE;
 203         }
 204 }
 205
 206 /*
 207  * Some ring helper functions. We don't assume size is a power of 2 so
 208  * we can't use circ_buf.h.
 209  */
 210 static inline size_t spc_used(size_t head, size_t tail, size_t size)
 211 {
 212         int diff = head - tail;
 213
 214         if (diff >= 0)
 215                 return diff;
 216         else
 217                 return size + diff;
 218 }
 219
 220 static inline size_t spc_free(size_t head, size_t tail, size_t size)
 221 {
 222         /* Keep 1 byte unused or we can't tell full from empty */
 223         return (size - spc_used(head, tail, size) - 1);
 224 }
 225
 226 static inline size_t head_to_end(size_t head, size_t size)
 227 {
 228         return size - head;
 229 }
 230
 231 static inline void new_iov(struct iovec **iov, int *iov_cnt,
 232                            struct tcmu_dev *udev)
 233 {
 234         struct iovec *iovec;
 235
 236         if (*iov_cnt != 0)
 237                 (*iov)++;
 238         (*iov_cnt)++;
 239
 240         iovec = *iov;
 241         memset(iovec, 0, sizeof(struct iovec));
 242 }
 243
 244 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
 245
 246 /* offset is relative to mb_addr */
 247 static inline size_t get_block_offset(struct tcmu_dev *dev,
 248                 int block, int remaining)
 249 {
 250         return dev->data_off + block * DATA_BLOCK_SIZE +
 251                 DATA_BLOCK_SIZE - remaining;
 252 }
 253
 254 static inline size_t iov_tail(struct tcmu_dev *udev, struct iovec *iov)
 255 {
 256         return (size_t)iov->iov_base + iov->iov_len;
 257 }
 258
 259 static void alloc_and_scatter_data_area(struct tcmu_dev *udev,
 260         struct scatterlist *data_sg, unsigned int data_nents,
 261         struct iovec **iov, int *iov_cnt, bool copy_data)
 262 {
 263         int i, block;
 264         int block_remaining = 0;
 265         void *from, *to;
 266         size_t copy_bytes, to_offset;
 267         struct scatterlist *sg;
 268
 269         for_each_sg(data_sg, sg, data_nents, i) {
 270                 int sg_remaining = sg->length;
 271                 from = kmap_atomic(sg_page(sg)) + sg->offset;
 272                 while (sg_remaining > 0) {
 273                         if (block_remaining == 0) {
 274                                 block = find_first_zero_bit(udev->data_bitmap,
 275                                                 DATA_BLOCK_BITS);
 276                                 block_remaining = DATA_BLOCK_SIZE;
 277                                 set_bit(block, udev->data_bitmap);
 278                         }
 279                         copy_bytes = min_t(size_t, sg_remaining,
 280                                         block_remaining);
 281                         to_offset = get_block_offset(udev, block,
 282                                         block_remaining);
 283                         to = (void *)udev->mb_addr + to_offset;
 284                         if (*iov_cnt != 0 &&
 285                             to_offset == iov_tail(udev, *iov)) {
 286                                 (*iov)->iov_len += copy_bytes;
 287                         } else {
 288                                 new_iov(iov, iov_cnt, udev);
 289                                 (*iov)->iov_base = (void __user *) to_offset;
 290                                 (*iov)->iov_len = copy_bytes;
 291                         }
 292                         if (copy_data) {
 293                                 memcpy(to, from + sg->length - sg_remaining,
 294                                         copy_bytes);
 295                                 tcmu_flush_dcache_range(to, copy_bytes);
 296                         }
 297                         sg_remaining -= copy_bytes;
 298                         block_remaining -= copy_bytes;
 299                 }
 300                 kunmap_atomic(from - sg->offset);
 301         }
 302 }
 303
 304 static void free_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd)
 305 {
 306         bitmap_xor(udev->data_bitmap, udev->data_bitmap, cmd->data_bitmap,
 307                    DATA_BLOCK_BITS);
 308 }
 309
 310 static void gather_data_area(struct tcmu_dev *udev, unsigned long *cmd_bitmap,
 311                 struct scatterlist *data_sg, unsigned int data_nents)
 312 {
 313         int i, block;
 314         int block_remaining = 0;
 315         void *from, *to;
 316         size_t copy_bytes, from_offset;
 317         struct scatterlist *sg;
 318
 319         for_each_sg(data_sg, sg, data_nents, i) {
 320                 int sg_remaining = sg->length;
 321                 to = kmap_atomic(sg_page(sg)) + sg->offset;
 322                 while (sg_remaining > 0) {
 323                         if (block_remaining == 0) {
 324                                 block = find_first_bit(cmd_bitmap,
 325                                                 DATA_BLOCK_BITS);
 326                                 block_remaining = DATA_BLOCK_SIZE;
 327                                 clear_bit(block, cmd_bitmap);
 328                         }
 329                         copy_bytes = min_t(size_t, sg_remaining,
 330                                         block_remaining);
 331                         from_offset = get_block_offset(udev, block,
 332                                         block_remaining);
 333                         from = (void *) udev->mb_addr + from_offset;
 334                         tcmu_flush_dcache_range(from, copy_bytes);
 335                         memcpy(to + sg->length - sg_remaining, from,
 336                                         copy_bytes);
 337
 338                         sg_remaining -= copy_bytes;
 339                         block_remaining -= copy_bytes;
 340                 }
 341                 kunmap_atomic(to - sg->offset);
 342         }
 343 }
 344
 345 static inline size_t spc_bitmap_free(unsigned long *bitmap)
 346 {
 347         return DATA_BLOCK_SIZE * (DATA_BLOCK_BITS -
 348                         bitmap_weight(bitmap, DATA_BLOCK_BITS));
 349 }
 350
 351 /*
 352  * We can't queue a command until we have space available on the cmd ring *and*
 353  * space available on the data area.
 354  *
 355  * Called with ring lock held.
 356  */
 357 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
 358 {
 359         struct tcmu_mailbox *mb = udev->mb_addr;
 360         size_t space, cmd_needed;
 361         u32 cmd_head;
 362
 363         tcmu_flush_dcache_range(mb, sizeof(*mb));
 364
 365         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 366
 367         /*
 368          * If cmd end-of-ring space is too small then we need space for a NOP plus
 369          * original cmd - cmds are internally contiguous.
 370          */
 371         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 372                 cmd_needed = cmd_size;
 373         else
 374                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 375
 376         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 377         if (space < cmd_needed) {
 378                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 379                        udev->cmdr_last_cleaned, udev->cmdr_size);
 380                 return false;
 381         }
 382
 383         space = spc_bitmap_free(udev->data_bitmap);
 384         if (space < data_needed) {
 385                 pr_debug("no data space: only %zu available, but ask for %zu\n",
 386                                 space, data_needed);
 387                 return false;
 388         }
 389
 390         return true;
 391 }
 392
 393 static sense_reason_t
 394 tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
 395 {
 396         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 397         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 398         size_t base_command_size, command_size;
 399         struct tcmu_mailbox *mb;
 400         struct tcmu_cmd_entry *entry;
 401         struct iovec *iov;
 402         int iov_cnt;
 403         uint32_t cmd_head;
 404         uint64_t cdb_off;
 405         bool copy_to_data_area;
 406         size_t data_length;
 407         DECLARE_BITMAP(old_bitmap, DATA_BLOCK_BITS);
 408
 409         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
 410                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 411
 412         /*
 413          * Must be a certain minimum size for response sense info, but
 414          * also may be larger if the iov array is large.
 415          *
 416          * We prepare way too many iovs for potential uses here, because it's
 417          * expensive to tell how many regions are freed in the bitmap
 418         */
 419         base_command_size = max(offsetof(struct tcmu_cmd_entry,
 420                                 req.iov[se_cmd->t_bidi_data_nents +
 421                                         se_cmd->t_data_nents]),
 422                                 sizeof(struct tcmu_cmd_entry));
 423         command_size = base_command_size
 424                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
 425
 426         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 427
 428         spin_lock_irq(&udev->cmdr_lock);
 429
 430         mb = udev->mb_addr;
 431         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 432         data_length = se_cmd->data_length;
 433         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 434                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
 435                 data_length += se_cmd->t_bidi_data_sg->length;
 436         }
 437         if ((command_size > (udev->cmdr_size / 2)) ||
 438             data_length > udev->data_size) {
 439                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
 440                         "cmd ring/data area\n", command_size, data_length,
 441                         udev->cmdr_size, udev->data_size);
 442                 spin_unlock_irq(&udev->cmdr_lock);
 443                 return TCM_INVALID_CDB_FIELD;
 444         }
 445
 446         while (!is_ring_space_avail(udev, command_size, data_length)) {
 447                 int ret;
 448                 DEFINE_WAIT(__wait);
 449
 450                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
 451
 452                 pr_debug("sleeping for ring space\n");
 453                 spin_unlock_irq(&udev->cmdr_lock);
 454                 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
 455                 finish_wait(&udev->wait_cmdr, &__wait);
 456                 if (!ret) {
 457                         pr_warn("tcmu: command timed out\n");
 458                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 459                 }
 460
 461                 spin_lock_irq(&udev->cmdr_lock);
 462
 463                 /* We dropped cmdr_lock, cmd_head is stale */
 464                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 465         }
 466
 467         /* Insert a PAD if end-of-ring space is too small */
 468         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
 469                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
 470
 471                 entry = (void *) mb + CMDR_OFF + cmd_head;
 472                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 473                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
 474                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
 475                 entry->hdr.cmd_id = 0; /* not used for PAD */
 476                 entry->hdr.kflags = 0;
 477                 entry->hdr.uflags = 0;
 478
 479                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
 480
 481                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 482                 WARN_ON(cmd_head != 0);
 483         }
 484
 485         entry = (void *) mb + CMDR_OFF + cmd_head;
 486         tcmu_flush_dcache_range(entry, sizeof(*entry));
 487         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
 488         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
 489         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
 490         entry->hdr.kflags = 0;
 491         entry->hdr.uflags = 0;
 492
 493         bitmap_copy(old_bitmap, udev->data_bitmap, DATA_BLOCK_BITS);
 494
 495         /* Handle allocating space from the data area */
 496         iov = &entry->req.iov[0];
 497         iov_cnt = 0;
 498         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
 499                 || se_cmd->se_cmd_flags & SCF_BIDI);
 500         alloc_and_scatter_data_area(udev, se_cmd->t_data_sg,
 501                 se_cmd->t_data_nents, &iov, &iov_cnt, copy_to_data_area);
 502         entry->req.iov_cnt = iov_cnt;
 503         entry->req.iov_dif_cnt = 0;
 504
 505         /* Handle BIDI commands */
 506         iov_cnt = 0;
 507         alloc_and_scatter_data_area(udev, se_cmd->t_bidi_data_sg,
 508                 se_cmd->t_bidi_data_nents, &iov, &iov_cnt, false);
 509         entry->req.iov_bidi_cnt = iov_cnt;
 510
 511         /* cmd's data_bitmap is what changed in process */
 512         bitmap_xor(tcmu_cmd->data_bitmap, old_bitmap, udev->data_bitmap,
 513                         DATA_BLOCK_BITS);
 514
 515         /* All offsets relative to mb_addr, not start of entry! */
 516         cdb_off = CMDR_OFF + cmd_head + base_command_size;
 517         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
 518         entry->req.cdb_off = cdb_off;
 519         tcmu_flush_dcache_range(entry, sizeof(*entry));
 520
 521         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
 522         tcmu_flush_dcache_range(mb, sizeof(*mb));
 523
 524         spin_unlock_irq(&udev->cmdr_lock);
 525
 526         /* TODO: only if FLUSH and FUA? */
 527         uio_event_notify(&udev->uio_info);
 528
 529         mod_timer(&udev->timeout,
 530                 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
 531
 532         return TCM_NO_SENSE;
 533 }
 534
 535 static sense_reason_t
 536 tcmu_queue_cmd(struct se_cmd *se_cmd)
 537 {
 538         struct se_device *se_dev = se_cmd->se_dev;
 539         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 540         struct tcmu_cmd *tcmu_cmd;
 541         sense_reason_t ret;
 542
 543         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
 544         if (!tcmu_cmd)
 545                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 546
 547         ret = tcmu_queue_cmd_ring(tcmu_cmd);
 548         if (ret != TCM_NO_SENSE) {
 549                 pr_err("TCMU: Could not queue command\n");
 550                 spin_lock_irq(&udev->commands_lock);
 551                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
 552                 spin_unlock_irq(&udev->commands_lock);
 553
 554                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 555         }
 556
 557         return ret;
 558 }
 559
 560 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
 561 {
 562         struct se_cmd *se_cmd = cmd->se_cmd;
 563         struct tcmu_dev *udev = cmd->tcmu_dev;
 564
 565         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 566                 /*
 567                  * cmd has been completed already from timeout, just reclaim
 568                  * data area space and free cmd
 569                  */
 570                 free_data_area(udev, cmd);
 571
 572                 kmem_cache_free(tcmu_cmd_cache, cmd);
 573                 return;
 574         }
 575
 576         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
 577                 free_data_area(udev, cmd);
 578                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
 579                         cmd->se_cmd);
 580                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
 581         } else if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
 582                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
 583                                se_cmd->scsi_sense_length);
 584                 free_data_area(udev, cmd);
 585         } else if (se_cmd->se_cmd_flags & SCF_BIDI) {
 586                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 587
 588                 /* Get Data-In buffer before clean up */
 589                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 590                 gather_data_area(udev, bitmap,
 591                         se_cmd->t_bidi_data_sg, se_cmd->t_bidi_data_nents);
 592                 free_data_area(udev, cmd);
 593         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
 594                 DECLARE_BITMAP(bitmap, DATA_BLOCK_BITS);
 595
 596                 bitmap_copy(bitmap, cmd->data_bitmap, DATA_BLOCK_BITS);
 597                 gather_data_area(udev, bitmap,
 598                         se_cmd->t_data_sg, se_cmd->t_data_nents);
 599                 free_data_area(udev, cmd);
 600         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 601                 free_data_area(udev, cmd);
 602         } else if (se_cmd->data_direction != DMA_NONE) {
 603                 pr_warn("TCMU: data direction was %d!\n",
 604                         se_cmd->data_direction);
 605         }
 606
 607         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
 608         cmd->se_cmd = NULL;
 609
 610         kmem_cache_free(tcmu_cmd_cache, cmd);
 611 }
 612
 613 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
 614 {
 615         struct tcmu_mailbox *mb;
 616         unsigned long flags;
 617         int handled = 0;
 618
 619         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 620                 pr_err("ring broken, not handling completions\n");
 621                 return 0;
 622         }
 623
 624         spin_lock_irqsave(&udev->cmdr_lock, flags);
 625
 626         mb = udev->mb_addr;
 627         tcmu_flush_dcache_range(mb, sizeof(*mb));
 628
 629         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
 630
 631                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
 632                 struct tcmu_cmd *cmd;
 633
 634                 tcmu_flush_dcache_range(entry, sizeof(*entry));
 635
 636                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
 637                         UPDATE_HEAD(udev->cmdr_last_cleaned,
 638                                     tcmu_hdr_get_len(entry->hdr.len_op),
 639                                     udev->cmdr_size);
 640                         continue;
 641                 }
 642                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
 643
 644                 spin_lock(&udev->commands_lock);
 645                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
 646                 spin_unlock(&udev->commands_lock);
 647
 648                 if (!cmd) {
 649                         pr_err("cmd_id not found, ring is broken\n");
 650                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
 651                         break;
 652                 }
 653
 654                 tcmu_handle_completion(cmd, entry);
 655
 656                 UPDATE_HEAD(udev->cmdr_last_cleaned,
 657                             tcmu_hdr_get_len(entry->hdr.len_op),
 658                             udev->cmdr_size);
 659
 660                 handled++;
 661         }
 662
 663         if (mb->cmd_tail == mb->cmd_head)
 664                 del_timer(&udev->timeout); /* no more pending cmds */
 665
 666         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
 667
 668         wake_up(&udev->wait_cmdr);
 669
 670         return handled;
 671 }
 672
 673 static int tcmu_check_expired_cmd(int id, void *p, void *data)
 674 {
 675         struct tcmu_cmd *cmd = p;
 676
 677         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
 678                 return 0;
 679
 680         if (!time_after(jiffies, cmd->deadline))
 681                 return 0;
 682
 683         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
 684         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
 685         cmd->se_cmd = NULL;
 686
 687         return 0;
 688 }
 689
 690 static void tcmu_device_timedout(unsigned long data)
 691 {
 692         struct tcmu_dev *udev = (struct tcmu_dev *)data;
 693         unsigned long flags;
 694         int handled;
 695
 696         handled = tcmu_handle_completions(udev);
 697
 698         pr_warn("%d completions handled from timeout\n", handled);
 699
 700         spin_lock_irqsave(&udev->commands_lock, flags);
 701         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
 702         spin_unlock_irqrestore(&udev->commands_lock, flags);
 703
 704         /*
 705          * We don't need to wakeup threads on wait_cmdr since they have their
 706          * own timeout.
 707          */
 708 }
 709
 710 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
 711 {
 712         struct tcmu_hba *tcmu_hba;
 713
 714         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
 715         if (!tcmu_hba)
 716                 return -ENOMEM;
 717
 718         tcmu_hba->host_id = host_id;
 719         hba->hba_ptr = tcmu_hba;
 720
 721         return 0;
 722 }
 723
 724 static void tcmu_detach_hba(struct se_hba *hba)
 725 {
 726         kfree(hba->hba_ptr);
 727         hba->hba_ptr = NULL;
 728 }
 729
 730 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
 731 {
 732         struct tcmu_dev *udev;
 733
 734         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
 735         if (!udev)
 736                 return NULL;
 737
 738         udev->name = kstrdup(name, GFP_KERNEL);
 739         if (!udev->name) {
 740                 kfree(udev);
 741                 return NULL;
 742         }
 743
 744         udev->hba = hba;
 745
 746         init_waitqueue_head(&udev->wait_cmdr);
 747         spin_lock_init(&udev->cmdr_lock);
 748
 749         idr_init(&udev->commands);
 750         spin_lock_init(&udev->commands_lock);
 751
 752         setup_timer(&udev->timeout, tcmu_device_timedout,
 753                 (unsigned long)udev);
 754
 755         return &udev->se_dev;
 756 }
 757
 758 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
 759 {
 760         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
 761
 762         tcmu_handle_completions(tcmu_dev);
 763
 764         return 0;
 765 }
 766
 767 /*
 768  * mmap code from uio.c. Copied here because we want to hook mmap()
 769  * and this stuff must come along.
 770  */
 771 static int tcmu_find_mem_index(struct vm_area_struct *vma)
 772 {
 773         struct tcmu_dev *udev = vma->vm_private_data;
 774         struct uio_info *info = &udev->uio_info;
 775
 776         if (vma->vm_pgoff < MAX_UIO_MAPS) {
 777                 if (info->mem[vma->vm_pgoff].size == 0)
 778                         return -1;
 779                 return (int)vma->vm_pgoff;
 780         }
 781         return -1;
 782 }
 783
 784 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 785 {
 786         struct tcmu_dev *udev = vma->vm_private_data;
 787         struct uio_info *info = &udev->uio_info;
 788         struct page *page;
 789         unsigned long offset;
 790         void *addr;
 791
 792         int mi = tcmu_find_mem_index(vma);
 793         if (mi < 0)
 794                 return VM_FAULT_SIGBUS;
 795
 796         /*
 797          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
 798          * to use mem[N].
 799          */
 800         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
 801
 802         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
 803         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
 804                 page = virt_to_page(addr);
 805         else
 806                 page = vmalloc_to_page(addr);
 807         get_page(page);
 808         vmf->page = page;
 809         return 0;
 810 }
 811
 812 static const struct vm_operations_struct tcmu_vm_ops = {
 813         .fault = tcmu_vma_fault,
 814 };
 815
 816 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
 817 {
 818         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 819
 820         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
 821         vma->vm_ops = &tcmu_vm_ops;
 822
 823         vma->vm_private_data = udev;
 824
 825         /* Ensure the mmap is exactly the right size */
 826         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
 827                 return -EINVAL;
 828
 829         return 0;
 830 }
 831
 832 static int tcmu_open(struct uio_info *info, struct inode *inode)
 833 {
 834         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 835
 836         /* O_EXCL not supported for char devs, so fake it? */
 837         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
 838                 return -EBUSY;
 839
 840         pr_debug("open\n");
 841
 842         return 0;
 843 }
 844
 845 static int tcmu_release(struct uio_info *info, struct inode *inode)
 846 {
 847         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
 848
 849         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
 850
 851         pr_debug("close\n");
 852
 853         return 0;
 854 }
 855
 856 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
 857 {
 858         struct sk_buff *skb;
 859         void *msg_header;
 860         int ret = -ENOMEM;
 861
 862         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 863         if (!skb)
 864                 return ret;
 865
 866         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
 867         if (!msg_header)
 868                 goto free_skb;
 869
 870         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
 871         if (ret < 0)
 872                 goto free_skb;
 873
 874         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
 875         if (ret < 0)
 876                 goto free_skb;
 877
 878         genlmsg_end(skb, msg_header);
 879
 880         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
 881                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
 882
 883         /* We don't care if no one is listening */
 884         if (ret == -ESRCH)
 885                 ret = 0;
 886
 887         return ret;
 888 free_skb:
 889         nlmsg_free(skb);
 890         return ret;
 891 }
 892
 893 static int tcmu_configure_device(struct se_device *dev)
 894 {
 895         struct tcmu_dev *udev = TCMU_DEV(dev);
 896         struct tcmu_hba *hba = udev->hba->hba_ptr;
 897         struct uio_info *info;
 898         struct tcmu_mailbox *mb;
 899         size_t size;
 900         size_t used;
 901         int ret = 0;
 902         char *str;
 903
 904         info = &udev->uio_info;
 905
 906         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
 907                         udev->dev_config);
 908         size += 1; /* for \0 */
 909         str = kmalloc(size, GFP_KERNEL);
 910         if (!str)
 911                 return -ENOMEM;
 912
 913         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
 914
 915         if (udev->dev_config[0])
 916                 snprintf(str + used, size - used, "/%s", udev->dev_config);
 917
 918         info->name = str;
 919
 920         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
 921         if (!udev->mb_addr) {
 922                 ret = -ENOMEM;
 923                 goto err_vzalloc;
 924         }
 925
 926         /* mailbox fits in first part of CMDR space */
 927         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
 928         udev->data_off = CMDR_SIZE;
 929         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
 930
 931         mb = udev->mb_addr;
 932         mb->version = TCMU_MAILBOX_VERSION;
 933         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC;
 934         mb->cmdr_off = CMDR_OFF;
 935         mb->cmdr_size = udev->cmdr_size;
 936
 937         WARN_ON(!PAGE_ALIGNED(udev->data_off));
 938         WARN_ON(udev->data_size % PAGE_SIZE);
 939         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
 940
 941         info->version = __stringify(TCMU_MAILBOX_VERSION);
 942
 943         info->mem[0].name = "tcm-user command & data buffer";
 944         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
 945         info->mem[0].size = TCMU_RING_SIZE;
 946         info->mem[0].memtype = UIO_MEM_VIRTUAL;
 947
 948         info->irqcontrol = tcmu_irqcontrol;
 949         info->irq = UIO_IRQ_CUSTOM;
 950
 951         info->mmap = tcmu_mmap;
 952         info->open = tcmu_open;
 953         info->release = tcmu_release;
 954
 955         ret = uio_register_device(tcmu_root_device, info);
 956         if (ret)
 957                 goto err_register;
 958
 959         /* User can set hw_block_size before enable the device */
 960         if (dev->dev_attrib.hw_block_size == 0)
 961                 dev->dev_attrib.hw_block_size = 512;
 962         /* Other attributes can be configured in userspace */
 963         dev->dev_attrib.hw_max_sectors = 128;
 964         dev->dev_attrib.hw_queue_depth = 128;
 965
 966         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
 967                                  udev->uio_info.uio_dev->minor);
 968         if (ret)
 969                 goto err_netlink;
 970
 971         return 0;
 972
 973 err_netlink:
 974         uio_unregister_device(&udev->uio_info);
 975 err_register:
 976         vfree(udev->mb_addr);
 977 err_vzalloc:
 978         kfree(info->name);
 979
 980         return ret;
 981 }
 982
 983 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
 984 {
 985         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
 986                 kmem_cache_free(tcmu_cmd_cache, cmd);
 987                 return 0;
 988         }
 989         return -EINVAL;
 990 }
 991
 992 static void tcmu_dev_call_rcu(struct rcu_head *p)
 993 {
 994         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 995         struct tcmu_dev *udev = TCMU_DEV(dev);
 996
 997         kfree(udev);
 998 }
 999
1000 static void tcmu_free_device(struct se_device *dev)
1001 {
1002         struct tcmu_dev *udev = TCMU_DEV(dev);
1003         struct tcmu_cmd *cmd;
1004         bool all_expired = true;
1005         int i;
1006
1007         del_timer_sync(&udev->timeout);
1008
1009         vfree(udev->mb_addr);
1010
1011         /* Upper layer should drain all requests before calling this */
1012         spin_lock_irq(&udev->commands_lock);
1013         idr_for_each_entry(&udev->commands, cmd, i) {
1014                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1015                         all_expired = false;
1016         }
1017         idr_destroy(&udev->commands);
1018         spin_unlock_irq(&udev->commands_lock);
1019         WARN_ON(!all_expired);
1020
1021         /* Device was configured */
1022         if (udev->uio_info.uio_dev) {
1023                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
1024                                    udev->uio_info.uio_dev->minor);
1025
1026                 uio_unregister_device(&udev->uio_info);
1027                 kfree(udev->uio_info.name);
1028                 kfree(udev->name);
1029         }
1030         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1031 }
1032
1033 enum {
1034         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err,
1035 };
1036
1037 static match_table_t tokens = {
1038         {Opt_dev_config, "dev_config=%s"},
1039         {Opt_dev_size, "dev_size=%u"},
1040         {Opt_hw_block_size, "hw_block_size=%u"},
1041         {Opt_err, NULL}
1042 };
1043
1044 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
1045                 const char *page, ssize_t count)
1046 {
1047         struct tcmu_dev *udev = TCMU_DEV(dev);
1048         char *orig, *ptr, *opts, *arg_p;
1049         substring_t args[MAX_OPT_ARGS];
1050         int ret = 0, token;
1051         unsigned long tmp_ul;
1052
1053         opts = kstrdup(page, GFP_KERNEL);
1054         if (!opts)
1055                 return -ENOMEM;
1056
1057         orig = opts;
1058
1059         while ((ptr = strsep(&opts, ",\n")) != NULL) {
1060                 if (!*ptr)
1061                         continue;
1062
1063                 token = match_token(ptr, tokens, args);
1064                 switch (token) {
1065                 case Opt_dev_config:
1066                         if (match_strlcpy(udev->dev_config, &args[0],
1067                                           TCMU_CONFIG_LEN) == 0) {
1068                                 ret = -EINVAL;
1069                                 break;
1070                         }
1071                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
1072                         break;
1073                 case Opt_dev_size:
1074                         arg_p = match_strdup(&args[0]);
1075                         if (!arg_p) {
1076                                 ret = -ENOMEM;
1077                                 break;
1078                         }
1079                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
1080                         kfree(arg_p);
1081                         if (ret < 0)
1082                                 pr_err("kstrtoul() failed for dev_size=\n");
1083                         break;
1084                 case Opt_hw_block_size:
1085                         arg_p = match_strdup(&args[0]);
1086                         if (!arg_p) {
1087                                 ret = -ENOMEM;
1088                                 break;
1089                         }
1090                         ret = kstrtoul(arg_p, 0, &tmp_ul);
1091                         kfree(arg_p);
1092                         if (ret < 0) {
1093                                 pr_err("kstrtoul() failed for hw_block_size=\n");
1094                                 break;
1095                         }
1096                         if (!tmp_ul) {
1097                                 pr_err("hw_block_size must be nonzero\n");
1098                                 break;
1099                         }
1100                         dev->dev_attrib.hw_block_size = tmp_ul;
1101                         break;
1102                 default:
1103                         break;
1104                 }
1105         }
1106
1107         kfree(orig);
1108         return (!ret) ? count : ret;
1109 }
1110
1111 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1112 {
1113         struct tcmu_dev *udev = TCMU_DEV(dev);
1114         ssize_t bl = 0;
1115
1116         bl = sprintf(b + bl, "Config: %s ",
1117                      udev->dev_config[0] ? udev->dev_config : "NULL");
1118         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1119
1120         return bl;
1121 }
1122
1123 static sector_t tcmu_get_blocks(struct se_device *dev)
1124 {
1125         struct tcmu_dev *udev = TCMU_DEV(dev);
1126
1127         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1128                        dev->dev_attrib.block_size);
1129 }
1130
1131 static sense_reason_t
1132 tcmu_parse_cdb(struct se_cmd *cmd)
1133 {
1134         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
1135 }
1136
1137 static const struct target_backend_ops tcmu_ops = {
1138         .name                   = "user",
1139         .owner                  = THIS_MODULE,
1140         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1141         .attach_hba             = tcmu_attach_hba,
1142         .detach_hba             = tcmu_detach_hba,
1143         .alloc_device           = tcmu_alloc_device,
1144         .configure_device       = tcmu_configure_device,
1145         .free_device            = tcmu_free_device,
1146         .parse_cdb              = tcmu_parse_cdb,
1147         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1148         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1149         .get_device_type        = sbc_get_device_type,
1150         .get_blocks             = tcmu_get_blocks,
1151         .tb_dev_attrib_attrs    = passthrough_attrib_attrs,
1152 };
1153
1154 static int __init tcmu_module_init(void)
1155 {
1156         int ret;
1157
1158         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1159
1160         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1161                                 sizeof(struct tcmu_cmd),
1162                                 __alignof__(struct tcmu_cmd),
1163                                 0, NULL);
1164         if (!tcmu_cmd_cache)
1165                 return -ENOMEM;
1166
1167         tcmu_root_device = root_device_register("tcm_user");
1168         if (IS_ERR(tcmu_root_device)) {
1169                 ret = PTR_ERR(tcmu_root_device);
1170                 goto out_free_cache;
1171         }
1172
1173         ret = genl_register_family(&tcmu_genl_family);
1174         if (ret < 0) {
1175                 goto out_unreg_device;
1176         }
1177
1178         ret = transport_backend_register(&tcmu_ops);
1179         if (ret)
1180                 goto out_unreg_genl;
1181
1182         return 0;
1183
1184 out_unreg_genl:
1185         genl_unregister_family(&tcmu_genl_family);
1186 out_unreg_device:
1187         root_device_unregister(tcmu_root_device);
1188 out_free_cache:
1189         kmem_cache_destroy(tcmu_cmd_cache);
1190
1191         return ret;
1192 }
1193
1194 static void __exit tcmu_module_exit(void)
1195 {
1196         target_backend_unregister(&tcmu_ops);
1197         genl_unregister_family(&tcmu_genl_family);
1198         root_device_unregister(tcmu_root_device);
1199         kmem_cache_destroy(tcmu_cmd_cache);
1200 }
1201
1202 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1203 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1204 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1205 MODULE_LICENSE("GPL");
1206
1207 module_init(tcmu_module_init);
1208 module_exit(tcmu_module_exit);