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