drivers/target/target_core_iblock.c

   1 /*******************************************************************************
   2  * Filename:  target_core_iblock.c
   3  *
   4  * This file contains the Storage Engine  <-> Linux BlockIO transport
   5  * specific functions.
   6  *
   7  * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
   8  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   9  * Copyright (c) 2007-2010 Rising Tide Systems
  10  * Copyright (c) 2008-2010 Linux-iSCSI.org
  11  *
  12  * Nicholas A. Bellinger <nab@kernel.org>
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  *
  28  ******************************************************************************/
  29
  30 #include <linux/version.h>
  31 #include <linux/string.h>
  32 #include <linux/parser.h>
  33 #include <linux/timer.h>
  34 #include <linux/fs.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/slab.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/bio.h>
  39 #include <linux/genhd.h>
  40 #include <linux/file.h>
  41 #include <scsi/scsi.h>
  42 #include <scsi/scsi_host.h>
  43
  44 #include <target/target_core_base.h>
  45 #include <target/target_core_device.h>
  46 #include <target/target_core_transport.h>
  47
  48 #include "target_core_iblock.h"
  49
  50 #if 0
  51 #define DEBUG_IBLOCK(x...) printk(x)
  52 #else
  53 #define DEBUG_IBLOCK(x...)
  54 #endif
  55
  56 static struct se_subsystem_api iblock_template;
  57
  58 static void iblock_bio_done(struct bio *, int);
  59
  60 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  61  *
  62  *
  63  */
  64 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  65 {
  66         struct iblock_hba *ib_host;
  67
  68         ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
  69         if (!(ib_host)) {
  70                 printk(KERN_ERR "Unable to allocate memory for"
  71                                 " struct iblock_hba\n");
  72                 return -ENOMEM;
  73         }
  74
  75         ib_host->iblock_host_id = host_id;
  76
  77         hba->hba_ptr = ib_host;
  78
  79         printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  80                 " Generic Target Core Stack %s\n", hba->hba_id,
  81                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  82
  83         printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic\n",
  84                 hba->hba_id, ib_host->iblock_host_id);
  85
  86         return 0;
  87 }
  88
  89 static void iblock_detach_hba(struct se_hba *hba)
  90 {
  91         struct iblock_hba *ib_host = hba->hba_ptr;
  92
  93         printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
  94                 " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
  95
  96         kfree(ib_host);
  97         hba->hba_ptr = NULL;
  98 }
  99
 100 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
 101 {
 102         struct iblock_dev *ib_dev = NULL;
 103         struct iblock_hba *ib_host = hba->hba_ptr;
 104
 105         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
 106         if (!(ib_dev)) {
 107                 printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
 108                 return NULL;
 109         }
 110         ib_dev->ibd_host = ib_host;
 111
 112         printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
 113
 114         return ib_dev;
 115 }
 116
 117 static struct se_device *iblock_create_virtdevice(
 118         struct se_hba *hba,
 119         struct se_subsystem_dev *se_dev,
 120         void *p)
 121 {
 122         struct iblock_dev *ib_dev = p;
 123         struct se_device *dev;
 124         struct se_dev_limits dev_limits;
 125         struct block_device *bd = NULL;
 126         struct request_queue *q;
 127         struct queue_limits *limits;
 128         u32 dev_flags = 0;
 129         int ret = -EINVAL;
 130
 131         if (!(ib_dev)) {
 132                 printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
 133                 return ERR_PTR(ret);
 134         }
 135         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 136         /*
 137          * These settings need to be made tunable..
 138          */
 139         ib_dev->ibd_bio_set = bioset_create(32, 64);
 140         if (!(ib_dev->ibd_bio_set)) {
 141                 printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
 142                 return ERR_PTR(-ENOMEM);
 143         }
 144         printk(KERN_INFO "IBLOCK: Created bio_set()\n");
 145         /*
 146          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 147          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 148          */
 149         printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
 150                         ib_dev->ibd_udev_path);
 151
 152         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
 153                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
 154         if (IS_ERR(bd)) {
 155                 ret = PTR_ERR(bd);
 156                 goto failed;
 157         }
 158         /*
 159          * Setup the local scope queue_limits from struct request_queue->limits
 160          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 161          */
 162         q = bdev_get_queue(bd);
 163         limits = &dev_limits.limits;
 164         limits->logical_block_size = bdev_logical_block_size(bd);
 165         limits->max_hw_sectors = queue_max_hw_sectors(q);
 166         limits->max_sectors = queue_max_sectors(q);
 167         dev_limits.hw_queue_depth = q->nr_requests;
 168         dev_limits.queue_depth = q->nr_requests;
 169
 170         ib_dev->ibd_major = MAJOR(bd->bd_dev);
 171         ib_dev->ibd_minor = MINOR(bd->bd_dev);
 172         ib_dev->ibd_bd = bd;
 173
 174         dev = transport_add_device_to_core_hba(hba,
 175                         &iblock_template, se_dev, dev_flags, ib_dev,
 176                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 177         if (!(dev))
 178                 goto failed;
 179
 180         ib_dev->ibd_depth = dev->queue_depth;
 181
 182         /*
 183          * Check if the underlying struct block_device request_queue supports
 184          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 185          * in ATA and we need to set TPE=1
 186          */
 187         if (blk_queue_discard(q)) {
 188                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 189                                 q->limits.max_discard_sectors;
 190                 /*
 191                  * Currently hardcoded to 1 in Linux/SCSI code..
 192                  */
 193                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 194                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 195                                 q->limits.discard_granularity;
 196                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 197                                 q->limits.discard_alignment;
 198
 199                 printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
 200                                 " disabled by default\n");
 201         }
 202
 203         return dev;
 204
 205 failed:
 206         if (ib_dev->ibd_bio_set) {
 207                 bioset_free(ib_dev->ibd_bio_set);
 208                 ib_dev->ibd_bio_set = NULL;
 209         }
 210         ib_dev->ibd_bd = NULL;
 211         ib_dev->ibd_major = 0;
 212         ib_dev->ibd_minor = 0;
 213         return ERR_PTR(ret);
 214 }
 215
 216 static void iblock_free_device(void *p)
 217 {
 218         struct iblock_dev *ib_dev = p;
 219
 220         if (ib_dev->ibd_bd != NULL)
 221                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 222         if (ib_dev->ibd_bio_set != NULL)
 223                 bioset_free(ib_dev->ibd_bio_set);
 224         kfree(ib_dev);
 225 }
 226
 227 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
 228 {
 229         return container_of(task, struct iblock_req, ib_task);
 230 }
 231
 232 static struct se_task *
 233 iblock_alloc_task(struct se_cmd *cmd)
 234 {
 235         struct iblock_req *ib_req;
 236
 237         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 238         if (!(ib_req)) {
 239                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
 240                 return NULL;
 241         }
 242
 243         ib_req->ib_dev = cmd->se_dev->dev_ptr;
 244         atomic_set(&ib_req->ib_bio_cnt, 0);
 245         return &ib_req->ib_task;
 246 }
 247
 248 static unsigned long long iblock_emulate_read_cap_with_block_size(
 249         struct se_device *dev,
 250         struct block_device *bd,
 251         struct request_queue *q)
 252 {
 253         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 254                                         bdev_logical_block_size(bd)) - 1);
 255         u32 block_size = bdev_logical_block_size(bd);
 256
 257         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 258                 return blocks_long;
 259
 260         switch (block_size) {
 261         case 4096:
 262                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 263                 case 2048:
 264                         blocks_long <<= 1;
 265                         break;
 266                 case 1024:
 267                         blocks_long <<= 2;
 268                         break;
 269                 case 512:
 270                         blocks_long <<= 3;
 271                 default:
 272                         break;
 273                 }
 274                 break;
 275         case 2048:
 276                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 277                 case 4096:
 278                         blocks_long >>= 1;
 279                         break;
 280                 case 1024:
 281                         blocks_long <<= 1;
 282                         break;
 283                 case 512:
 284                         blocks_long <<= 2;
 285                         break;
 286                 default:
 287                         break;
 288                 }
 289                 break;
 290         case 1024:
 291                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 292                 case 4096:
 293                         blocks_long >>= 2;
 294                         break;
 295                 case 2048:
 296                         blocks_long >>= 1;
 297                         break;
 298                 case 512:
 299                         blocks_long <<= 1;
 300                         break;
 301                 default:
 302                         break;
 303                 }
 304                 break;
 305         case 512:
 306                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 307                 case 4096:
 308                         blocks_long >>= 3;
 309                         break;
 310                 case 2048:
 311                         blocks_long >>= 2;
 312                         break;
 313                 case 1024:
 314                         blocks_long >>= 1;
 315                         break;
 316                 default:
 317                         break;
 318                 }
 319                 break;
 320         default:
 321                 break;
 322         }
 323
 324         return blocks_long;
 325 }
 326
 327 /*
 328  * Emulate SYCHRONIZE_CACHE_*
 329  */
 330 static void iblock_emulate_sync_cache(struct se_task *task)
 331 {
 332         struct se_cmd *cmd = task->task_se_cmd;
 333         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 334         int immed = (cmd->t_task_cdb[1] & 0x2);
 335         sector_t error_sector;
 336         int ret;
 337
 338         /*
 339          * If the Immediate bit is set, queue up the GOOD response
 340          * for this SYNCHRONIZE_CACHE op
 341          */
 342         if (immed)
 343                 transport_complete_sync_cache(cmd, 1);
 344
 345         /*
 346          * blkdev_issue_flush() does not support a specifying a range, so
 347          * we have to flush the entire cache.
 348          */
 349         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
 350         if (ret != 0) {
 351                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
 352                         " error_sector: %llu\n", ret,
 353                         (unsigned long long)error_sector);
 354         }
 355
 356         if (!immed)
 357                 transport_complete_sync_cache(cmd, ret == 0);
 358 }
 359
 360 /*
 361  * Tell TCM Core that we are capable of WriteCache emulation for
 362  * an underlying struct se_device.
 363  */
 364 static int iblock_emulated_write_cache(struct se_device *dev)
 365 {
 366         return 1;
 367 }
 368
 369 static int iblock_emulated_dpo(struct se_device *dev)
 370 {
 371         return 0;
 372 }
 373
 374 /*
 375  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
 376  * for TYPE_DISK.
 377  */
 378 static int iblock_emulated_fua_write(struct se_device *dev)
 379 {
 380         return 1;
 381 }
 382
 383 static int iblock_emulated_fua_read(struct se_device *dev)
 384 {
 385         return 0;
 386 }
 387
 388 static int iblock_do_task(struct se_task *task)
 389 {
 390         struct se_device *dev = task->task_se_cmd->se_dev;
 391         struct iblock_req *req = IBLOCK_REQ(task);
 392         struct bio *bio = req->ib_bio, *nbio = NULL;
 393         struct blk_plug plug;
 394         int rw;
 395
 396         if (task->task_data_direction == DMA_TO_DEVICE) {
 397                 /*
 398                  * Force data to disk if we pretend to not have a volatile
 399                  * write cache, or the initiator set the Force Unit Access bit.
 400                  */
 401                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 402                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 403                      task->task_se_cmd->t_tasks_fua))
 404                         rw = WRITE_FUA;
 405                 else
 406                         rw = WRITE;
 407         } else {
 408                 rw = READ;
 409         }
 410
 411         blk_start_plug(&plug);
 412         while (bio) {
 413                 nbio = bio->bi_next;
 414                 bio->bi_next = NULL;
 415                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
 416                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
 417
 418                 submit_bio(rw, bio);
 419                 bio = nbio;
 420         }
 421         blk_finish_plug(&plug);
 422
 423         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
 424 }
 425
 426 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
 427 {
 428         struct iblock_dev *ibd = dev->dev_ptr;
 429         struct block_device *bd = ibd->ibd_bd;
 430         int barrier = 0;
 431
 432         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
 433 }
 434
 435 static void iblock_free_task(struct se_task *task)
 436 {
 437         struct iblock_req *req = IBLOCK_REQ(task);
 438         struct bio *bio, *hbio = req->ib_bio;
 439         /*
 440          * We only release the bio(s) here if iblock_bio_done() has not called
 441          * bio_put() -> iblock_bio_destructor().
 442          */
 443         while (hbio != NULL) {
 444                 bio = hbio;
 445                 hbio = hbio->bi_next;
 446                 bio->bi_next = NULL;
 447                 bio_put(bio);
 448         }
 449
 450         kfree(req);
 451 }
 452
 453 enum {
 454         Opt_udev_path, Opt_force, Opt_err
 455 };
 456
 457 static match_table_t tokens = {
 458         {Opt_udev_path, "udev_path=%s"},
 459         {Opt_force, "force=%d"},
 460         {Opt_err, NULL}
 461 };
 462
 463 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 464                                                struct se_subsystem_dev *se_dev,
 465                                                const char *page, ssize_t count)
 466 {
 467         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 468         char *orig, *ptr, *arg_p, *opts;
 469         substring_t args[MAX_OPT_ARGS];
 470         int ret = 0, arg, token;
 471
 472         opts = kstrdup(page, GFP_KERNEL);
 473         if (!opts)
 474                 return -ENOMEM;
 475
 476         orig = opts;
 477
 478         while ((ptr = strsep(&opts, ",")) != NULL) {
 479                 if (!*ptr)
 480                         continue;
 481
 482                 token = match_token(ptr, tokens, args);
 483                 switch (token) {
 484                 case Opt_udev_path:
 485                         if (ib_dev->ibd_bd) {
 486                                 printk(KERN_ERR "Unable to set udev_path= while"
 487                                         " ib_dev->ibd_bd exists\n");
 488                                 ret = -EEXIST;
 489                                 goto out;
 490                         }
 491                         arg_p = match_strdup(&args[0]);
 492                         if (!arg_p) {
 493                                 ret = -ENOMEM;
 494                                 break;
 495                         }
 496                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 497                                         "%s", arg_p);
 498                         kfree(arg_p);
 499                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
 500                                         ib_dev->ibd_udev_path);
 501                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 502                         break;
 503                 case Opt_force:
 504                         match_int(args, &arg);
 505                         ib_dev->ibd_force = arg;
 506                         printk(KERN_INFO "IBLOCK: Set force=%d\n",
 507                                 ib_dev->ibd_force);
 508                         break;
 509                 default:
 510                         break;
 511                 }
 512         }
 513
 514 out:
 515         kfree(orig);
 516         return (!ret) ? count : ret;
 517 }
 518
 519 static ssize_t iblock_check_configfs_dev_params(
 520         struct se_hba *hba,
 521         struct se_subsystem_dev *se_dev)
 522 {
 523         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 524
 525         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 526                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
 527                 return -EINVAL;
 528         }
 529
 530         return 0;
 531 }
 532
 533 static ssize_t iblock_show_configfs_dev_params(
 534         struct se_hba *hba,
 535         struct se_subsystem_dev *se_dev,
 536         char *b)
 537 {
 538         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 539         struct block_device *bd = ibd->ibd_bd;
 540         char buf[BDEVNAME_SIZE];
 541         ssize_t bl = 0;
 542
 543         if (bd)
 544                 bl += sprintf(b + bl, "iBlock device: %s",
 545                                 bdevname(bd, buf));
 546         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
 547                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
 548                                 ibd->ibd_udev_path);
 549         } else
 550                 bl += sprintf(b + bl, "\n");
 551
 552         bl += sprintf(b + bl, "        ");
 553         if (bd) {
 554                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 555                         ibd->ibd_major, ibd->ibd_minor, (!bd->bd_contains) ?
 556                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
 557                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 558         } else {
 559                 bl += sprintf(b + bl, "Major: %d Minor: %d\n",
 560                         ibd->ibd_major, ibd->ibd_minor);
 561         }
 562
 563         return bl;
 564 }
 565
 566 static void iblock_bio_destructor(struct bio *bio)
 567 {
 568         struct se_task *task = bio->bi_private;
 569         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 570
 571         bio_free(bio, ib_dev->ibd_bio_set);
 572 }
 573
 574 static struct bio *iblock_get_bio(
 575         struct se_task *task,
 576         struct iblock_req *ib_req,
 577         struct iblock_dev *ib_dev,
 578         int *ret,
 579         sector_t lba,
 580         u32 sg_num)
 581 {
 582         struct bio *bio;
 583
 584         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 585         if (!(bio)) {
 586                 printk(KERN_ERR "Unable to allocate memory for bio\n");
 587                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
 588                 return NULL;
 589         }
 590
 591         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
 592                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
 593         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
 594
 595         bio->bi_bdev = ib_dev->ibd_bd;
 596         bio->bi_private = task;
 597         bio->bi_destructor = iblock_bio_destructor;
 598         bio->bi_end_io = &iblock_bio_done;
 599         bio->bi_sector = lba;
 600         atomic_inc(&ib_req->ib_bio_cnt);
 601
 602         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
 603         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
 604                         atomic_read(&ib_req->ib_bio_cnt));
 605         return bio;
 606 }
 607
 608 static int iblock_map_task_SG(struct se_task *task)
 609 {
 610         struct se_cmd *cmd = task->task_se_cmd;
 611         struct se_device *dev = cmd->se_dev;
 612         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 613         struct iblock_req *ib_req = IBLOCK_REQ(task);
 614         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
 615         struct scatterlist *sg;
 616         int ret = 0;
 617         u32 i, sg_num = task->task_sg_num;
 618         sector_t block_lba;
 619         /*
 620          * Do starting conversion up from non 512-byte blocksize with
 621          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
 622          */
 623         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 624                 block_lba = (task->task_lba << 3);
 625         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 626                 block_lba = (task->task_lba << 2);
 627         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 628                 block_lba = (task->task_lba << 1);
 629         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 630                 block_lba = task->task_lba;
 631         else {
 632                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
 633                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 634                 return PYX_TRANSPORT_LU_COMM_FAILURE;
 635         }
 636
 637         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
 638         if (!(bio))
 639                 return ret;
 640
 641         ib_req->ib_bio = bio;
 642         hbio = tbio = bio;
 643         /*
 644          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
 645          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
 646          */
 647         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
 648                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
 649                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
 650                                 sg->length, sg->offset);
 651 again:
 652                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
 653                 if (ret != sg->length) {
 654
 655                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
 656                                         bio->bi_sector);
 657                         DEBUG_IBLOCK("** task->task_size: %u\n",
 658                                         task->task_size);
 659                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
 660                                         bio->bi_max_vecs);
 661                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
 662                                         bio->bi_vcnt);
 663
 664                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
 665                                                 block_lba, sg_num);
 666                         if (!(bio))
 667                                 goto fail;
 668
 669                         tbio = tbio->bi_next = bio;
 670                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
 671                                 " list, Going to again\n", bio);
 672                         goto again;
 673                 }
 674                 /* Always in 512 byte units for Linux/Block */
 675                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 676                 sg_num--;
 677                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
 678                         " sg_num to %u\n", task, sg_num);
 679                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
 680                                 " to %llu\n", task, block_lba);
 681                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
 682                                 " %u\n", task, bio->bi_vcnt);
 683         }
 684
 685         return 0;
 686 fail:
 687         while (hbio) {
 688                 bio = hbio;
 689                 hbio = hbio->bi_next;
 690                 bio->bi_next = NULL;
 691                 bio_put(bio);
 692         }
 693         return ret;
 694 }
 695
 696 static unsigned char *iblock_get_cdb(struct se_task *task)
 697 {
 698         return IBLOCK_REQ(task)->ib_scsi_cdb;
 699 }
 700
 701 static u32 iblock_get_device_rev(struct se_device *dev)
 702 {
 703         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 704 }
 705
 706 static u32 iblock_get_device_type(struct se_device *dev)
 707 {
 708         return TYPE_DISK;
 709 }
 710
 711 static sector_t iblock_get_blocks(struct se_device *dev)
 712 {
 713         struct iblock_dev *ibd = dev->dev_ptr;
 714         struct block_device *bd = ibd->ibd_bd;
 715         struct request_queue *q = bdev_get_queue(bd);
 716
 717         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 718 }
 719
 720 static void iblock_bio_done(struct bio *bio, int err)
 721 {
 722         struct se_task *task = bio->bi_private;
 723         struct iblock_req *ibr = IBLOCK_REQ(task);
 724         /*
 725          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 726          */
 727         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
 728                 err = -EIO;
 729
 730         if (err != 0) {
 731                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
 732                         " err: %d\n", bio, err);
 733                 /*
 734                  * Bump the ib_bio_err_cnt and release bio.
 735                  */
 736                 atomic_inc(&ibr->ib_bio_err_cnt);
 737                 smp_mb__after_atomic_inc();
 738                 bio_put(bio);
 739                 /*
 740                  * Wait to complete the task until the last bio as completed.
 741                  */
 742                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 743                         return;
 744
 745                 ibr->ib_bio = NULL;
 746                 transport_complete_task(task, 0);
 747                 return;
 748         }
 749         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
 750                 task, bio, task->task_lba, bio->bi_sector, err);
 751         /*
 752          * bio_put() will call iblock_bio_destructor() to release the bio back
 753          * to ibr->ib_bio_set.
 754          */
 755         bio_put(bio);
 756         /*
 757          * Wait to complete the task until the last bio as completed.
 758          */
 759         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 760                 return;
 761         /*
 762          * Return GOOD status for task if zero ib_bio_err_cnt exists.
 763          */
 764         ibr->ib_bio = NULL;
 765         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
 766 }
 767
 768 static struct se_subsystem_api iblock_template = {
 769         .name                   = "iblock",
 770         .owner                  = THIS_MODULE,
 771         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 772         .map_task_SG            = iblock_map_task_SG,
 773         .attach_hba             = iblock_attach_hba,
 774         .detach_hba             = iblock_detach_hba,
 775         .allocate_virtdevice    = iblock_allocate_virtdevice,
 776         .create_virtdevice      = iblock_create_virtdevice,
 777         .free_device            = iblock_free_device,
 778         .dpo_emulated           = iblock_emulated_dpo,
 779         .fua_write_emulated     = iblock_emulated_fua_write,
 780         .fua_read_emulated      = iblock_emulated_fua_read,
 781         .write_cache_emulated   = iblock_emulated_write_cache,
 782         .alloc_task             = iblock_alloc_task,
 783         .do_task                = iblock_do_task,
 784         .do_discard             = iblock_do_discard,
 785         .do_sync_cache          = iblock_emulate_sync_cache,
 786         .free_task              = iblock_free_task,
 787         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 788         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 789         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 790         .get_cdb                = iblock_get_cdb,
 791         .get_device_rev         = iblock_get_device_rev,
 792         .get_device_type        = iblock_get_device_type,
 793         .get_blocks             = iblock_get_blocks,
 794 };
 795
 796 static int __init iblock_module_init(void)
 797 {
 798         return transport_subsystem_register(&iblock_template);
 799 }
 800
 801 static void iblock_module_exit(void)
 802 {
 803         transport_subsystem_release(&iblock_template);
 804 }
 805
 806 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 807 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 808 MODULE_LICENSE("GPL");
 809
 810 module_init(iblock_module_init);
 811 module_exit(iblock_module_exit);