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/string.h>
  31 #include <linux/parser.h>
  32 #include <linux/timer.h>
  33 #include <linux/fs.h>
  34 #include <linux/blkdev.h>
  35 #include <linux/slab.h>
  36 #include <linux/spinlock.h>
  37 #include <linux/bio.h>
  38 #include <linux/genhd.h>
  39 #include <linux/file.h>
  40 #include <linux/module.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_backend.h>
  46
  47 #include "target_core_iblock.h"
  48
  49 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  50 #define IBLOCK_BIO_POOL_SIZE    128
  51
  52 static struct se_subsystem_api iblock_template;
  53
  54 static void iblock_bio_done(struct bio *, int);
  55
  56 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  57  *
  58  *
  59  */
  60 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  61 {
  62         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  63                 " Generic Target Core Stack %s\n", hba->hba_id,
  64                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  65         return 0;
  66 }
  67
  68 static void iblock_detach_hba(struct se_hba *hba)
  69 {
  70 }
  71
  72 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
  73 {
  74         struct iblock_dev *ib_dev = NULL;
  75
  76         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  77         if (!ib_dev) {
  78                 pr_err("Unable to allocate struct iblock_dev\n");
  79                 return NULL;
  80         }
  81
  82         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  83
  84         return ib_dev;
  85 }
  86
  87 static struct se_device *iblock_create_virtdevice(
  88         struct se_hba *hba,
  89         struct se_subsystem_dev *se_dev,
  90         void *p)
  91 {
  92         struct iblock_dev *ib_dev = p;
  93         struct se_device *dev;
  94         struct se_dev_limits dev_limits;
  95         struct block_device *bd = NULL;
  96         struct request_queue *q;
  97         struct queue_limits *limits;
  98         u32 dev_flags = 0;
  99         int ret = -EINVAL;
 100
 101         if (!ib_dev) {
 102                 pr_err("Unable to locate struct iblock_dev parameter\n");
 103                 return ERR_PTR(ret);
 104         }
 105         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 106
 107         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 108         if (!ib_dev->ibd_bio_set) {
 109                 pr_err("IBLOCK: Unable to create bioset()\n");
 110                 return ERR_PTR(-ENOMEM);
 111         }
 112         pr_debug("IBLOCK: Created bio_set()\n");
 113         /*
 114          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 115          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 116          */
 117         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 118                         ib_dev->ibd_udev_path);
 119
 120         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
 121                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
 122         if (IS_ERR(bd)) {
 123                 ret = PTR_ERR(bd);
 124                 goto failed;
 125         }
 126         /*
 127          * Setup the local scope queue_limits from struct request_queue->limits
 128          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 129          */
 130         q = bdev_get_queue(bd);
 131         limits = &dev_limits.limits;
 132         limits->logical_block_size = bdev_logical_block_size(bd);
 133         limits->max_hw_sectors = UINT_MAX;
 134         limits->max_sectors = UINT_MAX;
 135         dev_limits.hw_queue_depth = q->nr_requests;
 136         dev_limits.queue_depth = q->nr_requests;
 137
 138         ib_dev->ibd_bd = bd;
 139
 140         dev = transport_add_device_to_core_hba(hba,
 141                         &iblock_template, se_dev, dev_flags, ib_dev,
 142                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 143         if (!dev)
 144                 goto failed;
 145
 146         /*
 147          * Check if the underlying struct block_device request_queue supports
 148          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 149          * in ATA and we need to set TPE=1
 150          */
 151         if (blk_queue_discard(q)) {
 152                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 153                                 q->limits.max_discard_sectors;
 154                 /*
 155                  * Currently hardcoded to 1 in Linux/SCSI code..
 156                  */
 157                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 158                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 159                                 q->limits.discard_granularity >> 9;
 160                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 161                                 q->limits.discard_alignment;
 162
 163                 pr_debug("IBLOCK: BLOCK Discard support available,"
 164                                 " disabled by default\n");
 165         }
 166
 167         if (blk_queue_nonrot(q))
 168                 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
 169
 170         return dev;
 171
 172 failed:
 173         if (ib_dev->ibd_bio_set) {
 174                 bioset_free(ib_dev->ibd_bio_set);
 175                 ib_dev->ibd_bio_set = NULL;
 176         }
 177         ib_dev->ibd_bd = NULL;
 178         return ERR_PTR(ret);
 179 }
 180
 181 static void iblock_free_device(void *p)
 182 {
 183         struct iblock_dev *ib_dev = p;
 184
 185         if (ib_dev->ibd_bd != NULL)
 186                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 187         if (ib_dev->ibd_bio_set != NULL)
 188                 bioset_free(ib_dev->ibd_bio_set);
 189         kfree(ib_dev);
 190 }
 191
 192 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
 193 {
 194         return container_of(task, struct iblock_req, ib_task);
 195 }
 196
 197 static struct se_task *
 198 iblock_alloc_task(unsigned char *cdb)
 199 {
 200         struct iblock_req *ib_req;
 201
 202         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 203         if (!ib_req) {
 204                 pr_err("Unable to allocate memory for struct iblock_req\n");
 205                 return NULL;
 206         }
 207
 208         atomic_set(&ib_req->pending, 1);
 209         return &ib_req->ib_task;
 210 }
 211
 212 static unsigned long long iblock_emulate_read_cap_with_block_size(
 213         struct se_device *dev,
 214         struct block_device *bd,
 215         struct request_queue *q)
 216 {
 217         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 218                                         bdev_logical_block_size(bd)) - 1);
 219         u32 block_size = bdev_logical_block_size(bd);
 220
 221         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 222                 return blocks_long;
 223
 224         switch (block_size) {
 225         case 4096:
 226                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 227                 case 2048:
 228                         blocks_long <<= 1;
 229                         break;
 230                 case 1024:
 231                         blocks_long <<= 2;
 232                         break;
 233                 case 512:
 234                         blocks_long <<= 3;
 235                 default:
 236                         break;
 237                 }
 238                 break;
 239         case 2048:
 240                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 241                 case 4096:
 242                         blocks_long >>= 1;
 243                         break;
 244                 case 1024:
 245                         blocks_long <<= 1;
 246                         break;
 247                 case 512:
 248                         blocks_long <<= 2;
 249                         break;
 250                 default:
 251                         break;
 252                 }
 253                 break;
 254         case 1024:
 255                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 256                 case 4096:
 257                         blocks_long >>= 2;
 258                         break;
 259                 case 2048:
 260                         blocks_long >>= 1;
 261                         break;
 262                 case 512:
 263                         blocks_long <<= 1;
 264                         break;
 265                 default:
 266                         break;
 267                 }
 268                 break;
 269         case 512:
 270                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 271                 case 4096:
 272                         blocks_long >>= 3;
 273                         break;
 274                 case 2048:
 275                         blocks_long >>= 2;
 276                         break;
 277                 case 1024:
 278                         blocks_long >>= 1;
 279                         break;
 280                 default:
 281                         break;
 282                 }
 283                 break;
 284         default:
 285                 break;
 286         }
 287
 288         return blocks_long;
 289 }
 290
 291 static void iblock_end_io_flush(struct bio *bio, int err)
 292 {
 293         struct se_cmd *cmd = bio->bi_private;
 294
 295         if (err)
 296                 pr_err("IBLOCK: cache flush failed: %d\n", err);
 297
 298         if (cmd)
 299                 transport_complete_sync_cache(cmd, err == 0);
 300         bio_put(bio);
 301 }
 302
 303 /*
 304  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 305  * always flush the whole cache.
 306  */
 307 static void iblock_emulate_sync_cache(struct se_task *task)
 308 {
 309         struct se_cmd *cmd = task->task_se_cmd;
 310         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 311         int immed = (cmd->t_task_cdb[1] & 0x2);
 312         struct bio *bio;
 313
 314         /*
 315          * If the Immediate bit is set, queue up the GOOD response
 316          * for this SYNCHRONIZE_CACHE op.
 317          */
 318         if (immed)
 319                 transport_complete_sync_cache(cmd, 1);
 320
 321         bio = bio_alloc(GFP_KERNEL, 0);
 322         bio->bi_end_io = iblock_end_io_flush;
 323         bio->bi_bdev = ib_dev->ibd_bd;
 324         if (!immed)
 325                 bio->bi_private = cmd;
 326         submit_bio(WRITE_FLUSH, bio);
 327 }
 328
 329 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
 330 {
 331         struct iblock_dev *ibd = dev->dev_ptr;
 332         struct block_device *bd = ibd->ibd_bd;
 333         int barrier = 0;
 334
 335         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
 336 }
 337
 338 static void iblock_free_task(struct se_task *task)
 339 {
 340         kfree(IBLOCK_REQ(task));
 341 }
 342
 343 enum {
 344         Opt_udev_path, Opt_force, Opt_err
 345 };
 346
 347 static match_table_t tokens = {
 348         {Opt_udev_path, "udev_path=%s"},
 349         {Opt_force, "force=%d"},
 350         {Opt_err, NULL}
 351 };
 352
 353 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 354                                                struct se_subsystem_dev *se_dev,
 355                                                const char *page, ssize_t count)
 356 {
 357         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 358         char *orig, *ptr, *arg_p, *opts;
 359         substring_t args[MAX_OPT_ARGS];
 360         int ret = 0, token;
 361
 362         opts = kstrdup(page, GFP_KERNEL);
 363         if (!opts)
 364                 return -ENOMEM;
 365
 366         orig = opts;
 367
 368         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 369                 if (!*ptr)
 370                         continue;
 371
 372                 token = match_token(ptr, tokens, args);
 373                 switch (token) {
 374                 case Opt_udev_path:
 375                         if (ib_dev->ibd_bd) {
 376                                 pr_err("Unable to set udev_path= while"
 377                                         " ib_dev->ibd_bd exists\n");
 378                                 ret = -EEXIST;
 379                                 goto out;
 380                         }
 381                         arg_p = match_strdup(&args[0]);
 382                         if (!arg_p) {
 383                                 ret = -ENOMEM;
 384                                 break;
 385                         }
 386                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 387                                         "%s", arg_p);
 388                         kfree(arg_p);
 389                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 390                                         ib_dev->ibd_udev_path);
 391                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 392                         break;
 393                 case Opt_force:
 394                         break;
 395                 default:
 396                         break;
 397                 }
 398         }
 399
 400 out:
 401         kfree(orig);
 402         return (!ret) ? count : ret;
 403 }
 404
 405 static ssize_t iblock_check_configfs_dev_params(
 406         struct se_hba *hba,
 407         struct se_subsystem_dev *se_dev)
 408 {
 409         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 410
 411         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 412                 pr_err("Missing udev_path= parameters for IBLOCK\n");
 413                 return -EINVAL;
 414         }
 415
 416         return 0;
 417 }
 418
 419 static ssize_t iblock_show_configfs_dev_params(
 420         struct se_hba *hba,
 421         struct se_subsystem_dev *se_dev,
 422         char *b)
 423 {
 424         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 425         struct block_device *bd = ibd->ibd_bd;
 426         char buf[BDEVNAME_SIZE];
 427         ssize_t bl = 0;
 428
 429         if (bd)
 430                 bl += sprintf(b + bl, "iBlock device: %s",
 431                                 bdevname(bd, buf));
 432         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
 433                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
 434                                 ibd->ibd_udev_path);
 435         } else
 436                 bl += sprintf(b + bl, "\n");
 437
 438         bl += sprintf(b + bl, "        ");
 439         if (bd) {
 440                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 441                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 442                         "" : (bd->bd_holder == ibd) ?
 443                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 444         } else {
 445                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 446         }
 447
 448         return bl;
 449 }
 450
 451 static void iblock_bio_destructor(struct bio *bio)
 452 {
 453         struct se_task *task = bio->bi_private;
 454         struct iblock_dev *ib_dev = task->task_se_cmd->se_dev->dev_ptr;
 455
 456         bio_free(bio, ib_dev->ibd_bio_set);
 457 }
 458
 459 static struct bio *
 460 iblock_get_bio(struct se_task *task, sector_t lba, u32 sg_num)
 461 {
 462         struct iblock_dev *ib_dev = task->task_se_cmd->se_dev->dev_ptr;
 463         struct iblock_req *ib_req = IBLOCK_REQ(task);
 464         struct bio *bio;
 465
 466         /*
 467          * Only allocate as many vector entries as the bio code allows us to,
 468          * we'll loop later on until we have handled the whole request.
 469          */
 470         if (sg_num > BIO_MAX_PAGES)
 471                 sg_num = BIO_MAX_PAGES;
 472
 473         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 474         if (!bio) {
 475                 pr_err("Unable to allocate memory for bio\n");
 476                 return NULL;
 477         }
 478
 479         pr_debug("Allocated bio: %p task_sg_nents: %u using ibd_bio_set:"
 480                 " %p\n", bio, task->task_sg_nents, ib_dev->ibd_bio_set);
 481         pr_debug("Allocated bio: %p task_size: %u\n", bio, task->task_size);
 482
 483         bio->bi_bdev = ib_dev->ibd_bd;
 484         bio->bi_private = task;
 485         bio->bi_destructor = iblock_bio_destructor;
 486         bio->bi_end_io = &iblock_bio_done;
 487         bio->bi_sector = lba;
 488         atomic_inc(&ib_req->pending);
 489
 490         pr_debug("Set bio->bi_sector: %llu\n", (unsigned long long)bio->bi_sector);
 491         pr_debug("Set ib_req->pending: %d\n", atomic_read(&ib_req->pending));
 492         return bio;
 493 }
 494
 495 static void iblock_submit_bios(struct bio_list *list, int rw)
 496 {
 497         struct blk_plug plug;
 498         struct bio *bio;
 499
 500         blk_start_plug(&plug);
 501         while ((bio = bio_list_pop(list)))
 502                 submit_bio(rw, bio);
 503         blk_finish_plug(&plug);
 504 }
 505
 506 static int iblock_do_task(struct se_task *task)
 507 {
 508         struct se_cmd *cmd = task->task_se_cmd;
 509         struct se_device *dev = cmd->se_dev;
 510         struct iblock_req *ibr = IBLOCK_REQ(task);
 511         struct bio *bio;
 512         struct bio_list list;
 513         struct scatterlist *sg;
 514         u32 i, sg_num = task->task_sg_nents;
 515         sector_t block_lba;
 516         unsigned bio_cnt;
 517         int rw;
 518
 519         if (task->task_data_direction == DMA_TO_DEVICE) {
 520                 /*
 521                  * Force data to disk if we pretend to not have a volatile
 522                  * write cache, or the initiator set the Force Unit Access bit.
 523                  */
 524                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 525                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 526                      (cmd->se_cmd_flags & SCF_FUA)))
 527                         rw = WRITE_FUA;
 528                 else
 529                         rw = WRITE;
 530         } else {
 531                 rw = READ;
 532         }
 533
 534         /*
 535          * Do starting conversion up from non 512-byte blocksize with
 536          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
 537          */
 538         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 539                 block_lba = (task->task_lba << 3);
 540         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 541                 block_lba = (task->task_lba << 2);
 542         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 543                 block_lba = (task->task_lba << 1);
 544         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 545                 block_lba = task->task_lba;
 546         else {
 547                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 548                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 549                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 550                 return -ENOSYS;
 551         }
 552
 553         bio = iblock_get_bio(task, block_lba, sg_num);
 554         if (!bio) {
 555                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 556                 return -ENOMEM;
 557         }
 558
 559         bio_list_init(&list);
 560         bio_list_add(&list, bio);
 561         bio_cnt = 1;
 562
 563         for_each_sg(task->task_sg, sg, task->task_sg_nents, i) {
 564                 /*
 565                  * XXX: if the length the device accepts is shorter than the
 566                  *      length of the S/G list entry this will cause and
 567                  *      endless loop.  Better hope no driver uses huge pages.
 568                  */
 569                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 570                                 != sg->length) {
 571                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 572                                 iblock_submit_bios(&list, rw);
 573                                 bio_cnt = 0;
 574                         }
 575
 576                         bio = iblock_get_bio(task, block_lba, sg_num);
 577                         if (!bio)
 578                                 goto fail;
 579                         bio_list_add(&list, bio);
 580                         bio_cnt++;
 581                 }
 582
 583                 /* Always in 512 byte units for Linux/Block */
 584                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 585                 sg_num--;
 586         }
 587
 588         iblock_submit_bios(&list, rw);
 589
 590         if (atomic_dec_and_test(&ibr->pending)) {
 591                 transport_complete_task(task,
 592                                 !atomic_read(&ibr->ib_bio_err_cnt));
 593         }
 594         return 0;
 595
 596 fail:
 597         while ((bio = bio_list_pop(&list)))
 598                 bio_put(bio);
 599         cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 600         return -ENOMEM;
 601 }
 602
 603 static u32 iblock_get_device_rev(struct se_device *dev)
 604 {
 605         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 606 }
 607
 608 static u32 iblock_get_device_type(struct se_device *dev)
 609 {
 610         return TYPE_DISK;
 611 }
 612
 613 static sector_t iblock_get_blocks(struct se_device *dev)
 614 {
 615         struct iblock_dev *ibd = dev->dev_ptr;
 616         struct block_device *bd = ibd->ibd_bd;
 617         struct request_queue *q = bdev_get_queue(bd);
 618
 619         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 620 }
 621
 622 static void iblock_bio_done(struct bio *bio, int err)
 623 {
 624         struct se_task *task = bio->bi_private;
 625         struct iblock_req *ibr = IBLOCK_REQ(task);
 626
 627         /*
 628          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 629          */
 630         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 631                 err = -EIO;
 632
 633         if (err != 0) {
 634                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 635                         " err: %d\n", bio, err);
 636                 /*
 637                  * Bump the ib_bio_err_cnt and release bio.
 638                  */
 639                 atomic_inc(&ibr->ib_bio_err_cnt);
 640                 smp_mb__after_atomic_inc();
 641         }
 642
 643         bio_put(bio);
 644
 645         if (!atomic_dec_and_test(&ibr->pending))
 646                 return;
 647
 648         pr_debug("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
 649                  task, bio, task->task_lba,
 650                  (unsigned long long)bio->bi_sector, err);
 651
 652         transport_complete_task(task, !atomic_read(&ibr->ib_bio_err_cnt));
 653 }
 654
 655 static struct se_subsystem_api iblock_template = {
 656         .name                   = "iblock",
 657         .owner                  = THIS_MODULE,
 658         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 659         .write_cache_emulated   = 1,
 660         .fua_write_emulated     = 1,
 661         .attach_hba             = iblock_attach_hba,
 662         .detach_hba             = iblock_detach_hba,
 663         .allocate_virtdevice    = iblock_allocate_virtdevice,
 664         .create_virtdevice      = iblock_create_virtdevice,
 665         .free_device            = iblock_free_device,
 666         .alloc_task             = iblock_alloc_task,
 667         .do_task                = iblock_do_task,
 668         .do_discard             = iblock_do_discard,
 669         .do_sync_cache          = iblock_emulate_sync_cache,
 670         .free_task              = iblock_free_task,
 671         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 672         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 673         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 674         .get_device_rev         = iblock_get_device_rev,
 675         .get_device_type        = iblock_get_device_type,
 676         .get_blocks             = iblock_get_blocks,
 677 };
 678
 679 static int __init iblock_module_init(void)
 680 {
 681         return transport_subsystem_register(&iblock_template);
 682 }
 683
 684 static void iblock_module_exit(void)
 685 {
 686         transport_subsystem_release(&iblock_template);
 687 }
 688
 689 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 690 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 691 MODULE_LICENSE("GPL");
 692
 693 module_init(iblock_module_init);
 694 module_exit(iblock_module_exit);