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 #include <asm/unaligned.h>
  44
  45 #include <target/target_core_base.h>
  46 #include <target/target_core_backend.h>
  47
  48 #include "target_core_iblock.h"
  49
  50 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  51 #define IBLOCK_BIO_POOL_SIZE    128
  52
  53 static struct se_subsystem_api iblock_template;
  54
  55 static void iblock_bio_done(struct bio *, int);
  56
  57 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  58  *
  59  *
  60  */
  61 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  62 {
  63         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  64                 " Generic Target Core Stack %s\n", hba->hba_id,
  65                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  66         return 0;
  67 }
  68
  69 static void iblock_detach_hba(struct se_hba *hba)
  70 {
  71 }
  72
  73 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
  74 {
  75         struct iblock_dev *ib_dev = NULL;
  76
  77         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  78         if (!ib_dev) {
  79                 pr_err("Unable to allocate struct iblock_dev\n");
  80                 return NULL;
  81         }
  82
  83         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  84
  85         return ib_dev;
  86 }
  87
  88 static struct se_device *iblock_create_virtdevice(
  89         struct se_hba *hba,
  90         struct se_subsystem_dev *se_dev,
  91         void *p)
  92 {
  93         struct iblock_dev *ib_dev = p;
  94         struct se_device *dev;
  95         struct se_dev_limits dev_limits;
  96         struct block_device *bd = NULL;
  97         struct request_queue *q;
  98         struct queue_limits *limits;
  99         u32 dev_flags = 0;
 100         fmode_t mode;
 101         int ret = -EINVAL;
 102
 103         if (!ib_dev) {
 104                 pr_err("Unable to locate struct iblock_dev parameter\n");
 105                 return ERR_PTR(ret);
 106         }
 107         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 108
 109         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 110         if (!ib_dev->ibd_bio_set) {
 111                 pr_err("IBLOCK: Unable to create bioset()\n");
 112                 return ERR_PTR(-ENOMEM);
 113         }
 114         pr_debug("IBLOCK: Created bio_set()\n");
 115         /*
 116          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 117          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 118          */
 119         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 120                         ib_dev->ibd_udev_path);
 121
 122         mode = FMODE_READ|FMODE_EXCL;
 123         if (!ib_dev->ibd_readonly)
 124                 mode |= FMODE_WRITE;
 125
 126         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 127         if (IS_ERR(bd)) {
 128                 ret = PTR_ERR(bd);
 129                 goto failed;
 130         }
 131         /*
 132          * Setup the local scope queue_limits from struct request_queue->limits
 133          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 134          */
 135         q = bdev_get_queue(bd);
 136         limits = &dev_limits.limits;
 137         limits->logical_block_size = bdev_logical_block_size(bd);
 138         limits->max_hw_sectors = UINT_MAX;
 139         limits->max_sectors = UINT_MAX;
 140         dev_limits.hw_queue_depth = q->nr_requests;
 141         dev_limits.queue_depth = q->nr_requests;
 142
 143         ib_dev->ibd_bd = bd;
 144
 145         dev = transport_add_device_to_core_hba(hba,
 146                         &iblock_template, se_dev, dev_flags, ib_dev,
 147                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 148         if (!dev)
 149                 goto failed;
 150
 151         /*
 152          * Check if the underlying struct block_device request_queue supports
 153          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 154          * in ATA and we need to set TPE=1
 155          */
 156         if (blk_queue_discard(q)) {
 157                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 158                                 q->limits.max_discard_sectors;
 159                 /*
 160                  * Currently hardcoded to 1 in Linux/SCSI code..
 161                  */
 162                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 163                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 164                                 q->limits.discard_granularity >> 9;
 165                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 166                                 q->limits.discard_alignment;
 167
 168                 pr_debug("IBLOCK: BLOCK Discard support available,"
 169                                 " disabled by default\n");
 170         }
 171
 172         if (blk_queue_nonrot(q))
 173                 dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
 174
 175         return dev;
 176
 177 failed:
 178         if (ib_dev->ibd_bio_set) {
 179                 bioset_free(ib_dev->ibd_bio_set);
 180                 ib_dev->ibd_bio_set = NULL;
 181         }
 182         ib_dev->ibd_bd = NULL;
 183         return ERR_PTR(ret);
 184 }
 185
 186 static void iblock_free_device(void *p)
 187 {
 188         struct iblock_dev *ib_dev = p;
 189
 190         if (ib_dev->ibd_bd != NULL)
 191                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 192         if (ib_dev->ibd_bio_set != NULL)
 193                 bioset_free(ib_dev->ibd_bio_set);
 194         kfree(ib_dev);
 195 }
 196
 197 static unsigned long long iblock_emulate_read_cap_with_block_size(
 198         struct se_device *dev,
 199         struct block_device *bd,
 200         struct request_queue *q)
 201 {
 202         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 203                                         bdev_logical_block_size(bd)) - 1);
 204         u32 block_size = bdev_logical_block_size(bd);
 205
 206         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 207                 return blocks_long;
 208
 209         switch (block_size) {
 210         case 4096:
 211                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 212                 case 2048:
 213                         blocks_long <<= 1;
 214                         break;
 215                 case 1024:
 216                         blocks_long <<= 2;
 217                         break;
 218                 case 512:
 219                         blocks_long <<= 3;
 220                 default:
 221                         break;
 222                 }
 223                 break;
 224         case 2048:
 225                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 226                 case 4096:
 227                         blocks_long >>= 1;
 228                         break;
 229                 case 1024:
 230                         blocks_long <<= 1;
 231                         break;
 232                 case 512:
 233                         blocks_long <<= 2;
 234                         break;
 235                 default:
 236                         break;
 237                 }
 238                 break;
 239         case 1024:
 240                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 241                 case 4096:
 242                         blocks_long >>= 2;
 243                         break;
 244                 case 2048:
 245                         blocks_long >>= 1;
 246                         break;
 247                 case 512:
 248                         blocks_long <<= 1;
 249                         break;
 250                 default:
 251                         break;
 252                 }
 253                 break;
 254         case 512:
 255                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 256                 case 4096:
 257                         blocks_long >>= 3;
 258                         break;
 259                 case 2048:
 260                         blocks_long >>= 2;
 261                         break;
 262                 case 1024:
 263                         blocks_long >>= 1;
 264                         break;
 265                 default:
 266                         break;
 267                 }
 268                 break;
 269         default:
 270                 break;
 271         }
 272
 273         return blocks_long;
 274 }
 275
 276 static void iblock_end_io_flush(struct bio *bio, int err)
 277 {
 278         struct se_cmd *cmd = bio->bi_private;
 279
 280         if (err)
 281                 pr_err("IBLOCK: cache flush failed: %d\n", err);
 282
 283         if (cmd) {
 284                 if (err) {
 285                         cmd->scsi_sense_reason =
 286                                 TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 287                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 288                 } else {
 289                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 290                 }
 291         }
 292
 293         bio_put(bio);
 294 }
 295
 296 /*
 297  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 298  * always flush the whole cache.
 299  */
 300 static int iblock_execute_sync_cache(struct se_cmd *cmd)
 301 {
 302         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 303         int immed = (cmd->t_task_cdb[1] & 0x2);
 304         struct bio *bio;
 305
 306         /*
 307          * If the Immediate bit is set, queue up the GOOD response
 308          * for this SYNCHRONIZE_CACHE op.
 309          */
 310         if (immed)
 311                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 312
 313         bio = bio_alloc(GFP_KERNEL, 0);
 314         bio->bi_end_io = iblock_end_io_flush;
 315         bio->bi_bdev = ib_dev->ibd_bd;
 316         if (!immed)
 317                 bio->bi_private = cmd;
 318         submit_bio(WRITE_FLUSH, bio);
 319         return 0;
 320 }
 321
 322 static int iblock_execute_unmap(struct se_cmd *cmd)
 323 {
 324         struct se_device *dev = cmd->se_dev;
 325         struct iblock_dev *ibd = dev->dev_ptr;
 326         unsigned char *buf, *ptr = NULL;
 327         sector_t lba;
 328         int size;
 329         u32 range;
 330         int ret = 0;
 331         int dl, bd_dl;
 332
 333         if (cmd->data_length < 8) {
 334                 pr_warn("UNMAP parameter list length %u too small\n",
 335                         cmd->data_length);
 336                 cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 337                 return -EINVAL;
 338         }
 339
 340         buf = transport_kmap_data_sg(cmd);
 341
 342         dl = get_unaligned_be16(&buf[0]);
 343         bd_dl = get_unaligned_be16(&buf[2]);
 344
 345         size = cmd->data_length - 8;
 346         if (bd_dl > size)
 347                 pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
 348                         cmd->data_length, bd_dl);
 349         else
 350                 size = bd_dl;
 351
 352         if (size / 16 > dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count) {
 353                 cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 354                 ret = -EINVAL;
 355                 goto err;
 356         }
 357
 358         /* First UNMAP block descriptor starts at 8 byte offset */
 359         ptr = &buf[8];
 360         pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
 361                 " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
 362
 363         while (size >= 16) {
 364                 lba = get_unaligned_be64(&ptr[0]);
 365                 range = get_unaligned_be32(&ptr[8]);
 366                 pr_debug("UNMAP: Using lba: %llu and range: %u\n",
 367                                  (unsigned long long)lba, range);
 368
 369                 if (range > dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count) {
 370                         cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 371                         ret = -EINVAL;
 372                         goto err;
 373                 }
 374
 375                 if (lba + range > dev->transport->get_blocks(dev) + 1) {
 376                         cmd->scsi_sense_reason = TCM_ADDRESS_OUT_OF_RANGE;
 377                         ret = -EINVAL;
 378                         goto err;
 379                 }
 380
 381                 ret = blkdev_issue_discard(ibd->ibd_bd, lba, range,
 382                                            GFP_KERNEL, 0);
 383                 if (ret < 0) {
 384                         pr_err("blkdev_issue_discard() failed: %d\n",
 385                                         ret);
 386                         goto err;
 387                 }
 388
 389                 ptr += 16;
 390                 size -= 16;
 391         }
 392
 393 err:
 394         transport_kunmap_data_sg(cmd);
 395         if (!ret)
 396                 target_complete_cmd(cmd, GOOD);
 397         return ret;
 398 }
 399
 400 static int iblock_execute_write_same(struct se_cmd *cmd)
 401 {
 402         struct iblock_dev *ibd = cmd->se_dev->dev_ptr;
 403         int ret;
 404
 405         ret = blkdev_issue_discard(ibd->ibd_bd, cmd->t_task_lba,
 406                                    spc_get_write_same_sectors(cmd), GFP_KERNEL,
 407                                    0);
 408         if (ret < 0) {
 409                 pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
 410                 return ret;
 411         }
 412
 413         target_complete_cmd(cmd, GOOD);
 414         return 0;
 415 }
 416
 417 enum {
 418         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 419 };
 420
 421 static match_table_t tokens = {
 422         {Opt_udev_path, "udev_path=%s"},
 423         {Opt_readonly, "readonly=%d"},
 424         {Opt_force, "force=%d"},
 425         {Opt_err, NULL}
 426 };
 427
 428 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 429                                                struct se_subsystem_dev *se_dev,
 430                                                const char *page, ssize_t count)
 431 {
 432         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 433         char *orig, *ptr, *arg_p, *opts;
 434         substring_t args[MAX_OPT_ARGS];
 435         int ret = 0, token;
 436         unsigned long tmp_readonly;
 437
 438         opts = kstrdup(page, GFP_KERNEL);
 439         if (!opts)
 440                 return -ENOMEM;
 441
 442         orig = opts;
 443
 444         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 445                 if (!*ptr)
 446                         continue;
 447
 448                 token = match_token(ptr, tokens, args);
 449                 switch (token) {
 450                 case Opt_udev_path:
 451                         if (ib_dev->ibd_bd) {
 452                                 pr_err("Unable to set udev_path= while"
 453                                         " ib_dev->ibd_bd exists\n");
 454                                 ret = -EEXIST;
 455                                 goto out;
 456                         }
 457                         arg_p = match_strdup(&args[0]);
 458                         if (!arg_p) {
 459                                 ret = -ENOMEM;
 460                                 break;
 461                         }
 462                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 463                                         "%s", arg_p);
 464                         kfree(arg_p);
 465                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 466                                         ib_dev->ibd_udev_path);
 467                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 468                         break;
 469                 case Opt_readonly:
 470                         arg_p = match_strdup(&args[0]);
 471                         if (!arg_p) {
 472                                 ret = -ENOMEM;
 473                                 break;
 474                         }
 475                         ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 476                         kfree(arg_p);
 477                         if (ret < 0) {
 478                                 pr_err("strict_strtoul() failed for"
 479                                                 " readonly=\n");
 480                                 goto out;
 481                         }
 482                         ib_dev->ibd_readonly = tmp_readonly;
 483                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 484                         break;
 485                 case Opt_force:
 486                         break;
 487                 default:
 488                         break;
 489                 }
 490         }
 491
 492 out:
 493         kfree(orig);
 494         return (!ret) ? count : ret;
 495 }
 496
 497 static ssize_t iblock_check_configfs_dev_params(
 498         struct se_hba *hba,
 499         struct se_subsystem_dev *se_dev)
 500 {
 501         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 502
 503         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 504                 pr_err("Missing udev_path= parameters for IBLOCK\n");
 505                 return -EINVAL;
 506         }
 507
 508         return 0;
 509 }
 510
 511 static ssize_t iblock_show_configfs_dev_params(
 512         struct se_hba *hba,
 513         struct se_subsystem_dev *se_dev,
 514         char *b)
 515 {
 516         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 517         struct block_device *bd = ibd->ibd_bd;
 518         char buf[BDEVNAME_SIZE];
 519         ssize_t bl = 0;
 520
 521         if (bd)
 522                 bl += sprintf(b + bl, "iBlock device: %s",
 523                                 bdevname(bd, buf));
 524         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH)
 525                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 526                                 ibd->ibd_udev_path);
 527         bl += sprintf(b + bl, "  readonly: %d\n", ibd->ibd_readonly);
 528
 529         bl += sprintf(b + bl, "        ");
 530         if (bd) {
 531                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 532                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 533                         "" : (bd->bd_holder == ibd) ?
 534                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 535         } else {
 536                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 537         }
 538
 539         return bl;
 540 }
 541
 542 static void iblock_complete_cmd(struct se_cmd *cmd)
 543 {
 544         struct iblock_req *ibr = cmd->priv;
 545         u8 status;
 546
 547         if (!atomic_dec_and_test(&ibr->pending))
 548                 return;
 549
 550         if (atomic_read(&ibr->ib_bio_err_cnt))
 551                 status = SAM_STAT_CHECK_CONDITION;
 552         else
 553                 status = SAM_STAT_GOOD;
 554
 555         target_complete_cmd(cmd, status);
 556         kfree(ibr);
 557 }
 558
 559 static void iblock_bio_destructor(struct bio *bio)
 560 {
 561         struct se_cmd *cmd = bio->bi_private;
 562         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 563
 564         bio_free(bio, ib_dev->ibd_bio_set);
 565 }
 566
 567 static struct bio *
 568 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 569 {
 570         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 571         struct bio *bio;
 572
 573         /*
 574          * Only allocate as many vector entries as the bio code allows us to,
 575          * we'll loop later on until we have handled the whole request.
 576          */
 577         if (sg_num > BIO_MAX_PAGES)
 578                 sg_num = BIO_MAX_PAGES;
 579
 580         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 581         if (!bio) {
 582                 pr_err("Unable to allocate memory for bio\n");
 583                 return NULL;
 584         }
 585
 586         bio->bi_bdev = ib_dev->ibd_bd;
 587         bio->bi_private = cmd;
 588         bio->bi_destructor = iblock_bio_destructor;
 589         bio->bi_end_io = &iblock_bio_done;
 590         bio->bi_sector = lba;
 591         return bio;
 592 }
 593
 594 static void iblock_submit_bios(struct bio_list *list, int rw)
 595 {
 596         struct blk_plug plug;
 597         struct bio *bio;
 598
 599         blk_start_plug(&plug);
 600         while ((bio = bio_list_pop(list)))
 601                 submit_bio(rw, bio);
 602         blk_finish_plug(&plug);
 603 }
 604
 605 static int iblock_execute_rw(struct se_cmd *cmd)
 606 {
 607         struct scatterlist *sgl = cmd->t_data_sg;
 608         u32 sgl_nents = cmd->t_data_nents;
 609         enum dma_data_direction data_direction = cmd->data_direction;
 610         struct se_device *dev = cmd->se_dev;
 611         struct iblock_req *ibr;
 612         struct bio *bio;
 613         struct bio_list list;
 614         struct scatterlist *sg;
 615         u32 sg_num = sgl_nents;
 616         sector_t block_lba;
 617         unsigned bio_cnt;
 618         int rw;
 619         int i;
 620
 621         if (data_direction == DMA_TO_DEVICE) {
 622                 /*
 623                  * Force data to disk if we pretend to not have a volatile
 624                  * write cache, or the initiator set the Force Unit Access bit.
 625                  */
 626                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 627                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 628                      (cmd->se_cmd_flags & SCF_FUA)))
 629                         rw = WRITE_FUA;
 630                 else
 631                         rw = WRITE;
 632         } else {
 633                 rw = READ;
 634         }
 635
 636         /*
 637          * Convert the blocksize advertised to the initiator to the 512 byte
 638          * units unconditionally used by the Linux block layer.
 639          */
 640         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 641                 block_lba = (cmd->t_task_lba << 3);
 642         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 643                 block_lba = (cmd->t_task_lba << 2);
 644         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 645                 block_lba = (cmd->t_task_lba << 1);
 646         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 647                 block_lba = cmd->t_task_lba;
 648         else {
 649                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 650                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 651                 cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 652                 return -ENOSYS;
 653         }
 654
 655         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 656         if (!ibr)
 657                 goto fail;
 658         cmd->priv = ibr;
 659
 660         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 661         if (!bio)
 662                 goto fail_free_ibr;
 663
 664         bio_list_init(&list);
 665         bio_list_add(&list, bio);
 666
 667         atomic_set(&ibr->pending, 2);
 668         bio_cnt = 1;
 669
 670         for_each_sg(sgl, sg, sgl_nents, i) {
 671                 /*
 672                  * XXX: if the length the device accepts is shorter than the
 673                  *      length of the S/G list entry this will cause and
 674                  *      endless loop.  Better hope no driver uses huge pages.
 675                  */
 676                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 677                                 != sg->length) {
 678                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 679                                 iblock_submit_bios(&list, rw);
 680                                 bio_cnt = 0;
 681                         }
 682
 683                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 684                         if (!bio)
 685                                 goto fail_put_bios;
 686
 687                         atomic_inc(&ibr->pending);
 688                         bio_list_add(&list, bio);
 689                         bio_cnt++;
 690                 }
 691
 692                 /* Always in 512 byte units for Linux/Block */
 693                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 694                 sg_num--;
 695         }
 696
 697         iblock_submit_bios(&list, rw);
 698         iblock_complete_cmd(cmd);
 699         return 0;
 700
 701 fail_put_bios:
 702         while ((bio = bio_list_pop(&list)))
 703                 bio_put(bio);
 704 fail_free_ibr:
 705         kfree(ibr);
 706         cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 707 fail:
 708         return -ENOMEM;
 709 }
 710
 711 static u32 iblock_get_device_rev(struct se_device *dev)
 712 {
 713         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 714 }
 715
 716 static u32 iblock_get_device_type(struct se_device *dev)
 717 {
 718         return TYPE_DISK;
 719 }
 720
 721 static sector_t iblock_get_blocks(struct se_device *dev)
 722 {
 723         struct iblock_dev *ibd = dev->dev_ptr;
 724         struct block_device *bd = ibd->ibd_bd;
 725         struct request_queue *q = bdev_get_queue(bd);
 726
 727         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 728 }
 729
 730 static void iblock_bio_done(struct bio *bio, int err)
 731 {
 732         struct se_cmd *cmd = bio->bi_private;
 733         struct iblock_req *ibr = cmd->priv;
 734
 735         /*
 736          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 737          */
 738         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 739                 err = -EIO;
 740
 741         if (err != 0) {
 742                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 743                         " err: %d\n", bio, err);
 744                 /*
 745                  * Bump the ib_bio_err_cnt and release bio.
 746                  */
 747                 atomic_inc(&ibr->ib_bio_err_cnt);
 748                 smp_mb__after_atomic_inc();
 749         }
 750
 751         bio_put(bio);
 752
 753         iblock_complete_cmd(cmd);
 754 }
 755
 756 static struct spc_ops iblock_spc_ops = {
 757         .execute_rw             = iblock_execute_rw,
 758         .execute_sync_cache     = iblock_execute_sync_cache,
 759         .execute_write_same     = iblock_execute_write_same,
 760         .execute_unmap          = iblock_execute_unmap,
 761 };
 762
 763 static int iblock_parse_cdb(struct se_cmd *cmd)
 764 {
 765         return sbc_parse_cdb(cmd, &iblock_spc_ops);
 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         .write_cache_emulated   = 1,
 773         .fua_write_emulated     = 1,
 774         .attach_hba             = iblock_attach_hba,
 775         .detach_hba             = iblock_detach_hba,
 776         .allocate_virtdevice    = iblock_allocate_virtdevice,
 777         .create_virtdevice      = iblock_create_virtdevice,
 778         .free_device            = iblock_free_device,
 779         .parse_cdb              = iblock_parse_cdb,
 780         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 781         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 782         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 783         .get_device_rev         = iblock_get_device_rev,
 784         .get_device_type        = iblock_get_device_type,
 785         .get_blocks             = iblock_get_blocks,
 786 };
 787
 788 static int __init iblock_module_init(void)
 789 {
 790         return transport_subsystem_register(&iblock_template);
 791 }
 792
 793 static void iblock_module_exit(void)
 794 {
 795         transport_subsystem_release(&iblock_template);
 796 }
 797
 798 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 799 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 800 MODULE_LICENSE("GPL");
 801
 802 module_init(iblock_module_init);
 803 module_exit(iblock_module_exit);