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  * (c) Copyright 2003-2012 RisingTide Systems LLC.
   8  *
   9  * Nicholas A. Bellinger <nab@kernel.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  *
  25  ******************************************************************************/
  26
  27 #include <linux/string.h>
  28 #include <linux/parser.h>
  29 #include <linux/timer.h>
  30 #include <linux/fs.h>
  31 #include <linux/blkdev.h>
  32 #include <linux/slab.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/bio.h>
  35 #include <linux/genhd.h>
  36 #include <linux/file.h>
  37 #include <linux/module.h>
  38 #include <scsi/scsi.h>
  39 #include <scsi/scsi_host.h>
  40 #include <asm/unaligned.h>
  41
  42 #include <target/target_core_base.h>
  43 #include <target/target_core_backend.h>
  44
  45 #include "target_core_iblock.h"
  46
  47 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  48 #define IBLOCK_BIO_POOL_SIZE    128
  49
  50 static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  51 {
  52         return container_of(dev, struct iblock_dev, dev);
  53 }
  54
  55
  56 static struct se_subsystem_api iblock_template;
  57
  58 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  59  *
  60  *
  61  */
  62 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  63 {
  64         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  65                 " Generic Target Core Stack %s\n", hba->hba_id,
  66                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  67         return 0;
  68 }
  69
  70 static void iblock_detach_hba(struct se_hba *hba)
  71 {
  72 }
  73
  74 static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
  75 {
  76         struct iblock_dev *ib_dev = NULL;
  77
  78         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  79         if (!ib_dev) {
  80                 pr_err("Unable to allocate struct iblock_dev\n");
  81                 return NULL;
  82         }
  83
  84         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  85
  86         return &ib_dev->dev;
  87 }
  88
  89 static int iblock_configure_device(struct se_device *dev)
  90 {
  91         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
  92         struct request_queue *q;
  93         struct block_device *bd = NULL;
  94         fmode_t mode;
  95         int ret = -ENOMEM;
  96
  97         if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
  98                 pr_err("Missing udev_path= parameters for IBLOCK\n");
  99                 return -EINVAL;
 100         }
 101
 102         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 103         if (!ib_dev->ibd_bio_set) {
 104                 pr_err("IBLOCK: Unable to create bioset\n");
 105                 goto out;
 106         }
 107
 108         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 109                         ib_dev->ibd_udev_path);
 110
 111         mode = FMODE_READ|FMODE_EXCL;
 112         if (!ib_dev->ibd_readonly)
 113                 mode |= FMODE_WRITE;
 114
 115         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 116         if (IS_ERR(bd)) {
 117                 ret = PTR_ERR(bd);
 118                 goto out_free_bioset;
 119         }
 120         ib_dev->ibd_bd = bd;
 121
 122         q = bdev_get_queue(bd);
 123
 124         dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
 125         dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 126         dev->dev_attrib.hw_queue_depth = q->nr_requests;
 127
 128         /*
 129          * Check if the underlying struct block_device request_queue supports
 130          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 131          * in ATA and we need to set TPE=1
 132          */
 133         if (blk_queue_discard(q)) {
 134                 dev->dev_attrib.max_unmap_lba_count =
 135                                 q->limits.max_discard_sectors;
 136
 137                 /*
 138                  * Currently hardcoded to 1 in Linux/SCSI code..
 139                  */
 140                 dev->dev_attrib.max_unmap_block_desc_count = 1;
 141                 dev->dev_attrib.unmap_granularity =
 142                                 q->limits.discard_granularity >> 9;
 143                 dev->dev_attrib.unmap_granularity_alignment =
 144                                 q->limits.discard_alignment;
 145
 146                 pr_debug("IBLOCK: BLOCK Discard support available,"
 147                                 " disabled by default\n");
 148         }
 149         /*
 150          * Enable write same emulation for IBLOCK and use 0xFFFF as
 151          * the smaller WRITE_SAME(10) only has a two-byte block count.
 152          */
 153         dev->dev_attrib.max_write_same_len = 0xFFFF;
 154
 155         if (blk_queue_nonrot(q))
 156                 dev->dev_attrib.is_nonrot = 1;
 157
 158         return 0;
 159
 160 out_free_bioset:
 161         bioset_free(ib_dev->ibd_bio_set);
 162         ib_dev->ibd_bio_set = NULL;
 163 out:
 164         return ret;
 165 }
 166
 167 static void iblock_free_device(struct se_device *dev)
 168 {
 169         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 170
 171         if (ib_dev->ibd_bd != NULL)
 172                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 173         if (ib_dev->ibd_bio_set != NULL)
 174                 bioset_free(ib_dev->ibd_bio_set);
 175         kfree(ib_dev);
 176 }
 177
 178 static unsigned long long iblock_emulate_read_cap_with_block_size(
 179         struct se_device *dev,
 180         struct block_device *bd,
 181         struct request_queue *q)
 182 {
 183         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 184                                         bdev_logical_block_size(bd)) - 1);
 185         u32 block_size = bdev_logical_block_size(bd);
 186
 187         if (block_size == dev->dev_attrib.block_size)
 188                 return blocks_long;
 189
 190         switch (block_size) {
 191         case 4096:
 192                 switch (dev->dev_attrib.block_size) {
 193                 case 2048:
 194                         blocks_long <<= 1;
 195                         break;
 196                 case 1024:
 197                         blocks_long <<= 2;
 198                         break;
 199                 case 512:
 200                         blocks_long <<= 3;
 201                 default:
 202                         break;
 203                 }
 204                 break;
 205         case 2048:
 206                 switch (dev->dev_attrib.block_size) {
 207                 case 4096:
 208                         blocks_long >>= 1;
 209                         break;
 210                 case 1024:
 211                         blocks_long <<= 1;
 212                         break;
 213                 case 512:
 214                         blocks_long <<= 2;
 215                         break;
 216                 default:
 217                         break;
 218                 }
 219                 break;
 220         case 1024:
 221                 switch (dev->dev_attrib.block_size) {
 222                 case 4096:
 223                         blocks_long >>= 2;
 224                         break;
 225                 case 2048:
 226                         blocks_long >>= 1;
 227                         break;
 228                 case 512:
 229                         blocks_long <<= 1;
 230                         break;
 231                 default:
 232                         break;
 233                 }
 234                 break;
 235         case 512:
 236                 switch (dev->dev_attrib.block_size) {
 237                 case 4096:
 238                         blocks_long >>= 3;
 239                         break;
 240                 case 2048:
 241                         blocks_long >>= 2;
 242                         break;
 243                 case 1024:
 244                         blocks_long >>= 1;
 245                         break;
 246                 default:
 247                         break;
 248                 }
 249                 break;
 250         default:
 251                 break;
 252         }
 253
 254         return blocks_long;
 255 }
 256
 257 static void iblock_complete_cmd(struct se_cmd *cmd)
 258 {
 259         struct iblock_req *ibr = cmd->priv;
 260         u8 status;
 261
 262         if (!atomic_dec_and_test(&ibr->pending))
 263                 return;
 264
 265         if (atomic_read(&ibr->ib_bio_err_cnt))
 266                 status = SAM_STAT_CHECK_CONDITION;
 267         else
 268                 status = SAM_STAT_GOOD;
 269
 270         target_complete_cmd(cmd, status);
 271         kfree(ibr);
 272 }
 273
 274 static void iblock_bio_done(struct bio *bio, int err)
 275 {
 276         struct se_cmd *cmd = bio->bi_private;
 277         struct iblock_req *ibr = cmd->priv;
 278
 279         /*
 280          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 281          */
 282         if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 283                 err = -EIO;
 284
 285         if (err != 0) {
 286                 pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 287                         " err: %d\n", bio, err);
 288                 /*
 289                  * Bump the ib_bio_err_cnt and release bio.
 290                  */
 291                 atomic_inc(&ibr->ib_bio_err_cnt);
 292                 smp_mb__after_atomic_inc();
 293         }
 294
 295         bio_put(bio);
 296
 297         iblock_complete_cmd(cmd);
 298 }
 299
 300 static struct bio *
 301 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 302 {
 303         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 304         struct bio *bio;
 305
 306         /*
 307          * Only allocate as many vector entries as the bio code allows us to,
 308          * we'll loop later on until we have handled the whole request.
 309          */
 310         if (sg_num > BIO_MAX_PAGES)
 311                 sg_num = BIO_MAX_PAGES;
 312
 313         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 314         if (!bio) {
 315                 pr_err("Unable to allocate memory for bio\n");
 316                 return NULL;
 317         }
 318
 319         bio->bi_bdev = ib_dev->ibd_bd;
 320         bio->bi_private = cmd;
 321         bio->bi_end_io = &iblock_bio_done;
 322         bio->bi_sector = lba;
 323
 324         return bio;
 325 }
 326
 327 static void iblock_submit_bios(struct bio_list *list, int rw)
 328 {
 329         struct blk_plug plug;
 330         struct bio *bio;
 331
 332         blk_start_plug(&plug);
 333         while ((bio = bio_list_pop(list)))
 334                 submit_bio(rw, bio);
 335         blk_finish_plug(&plug);
 336 }
 337
 338 static void iblock_end_io_flush(struct bio *bio, int err)
 339 {
 340         struct se_cmd *cmd = bio->bi_private;
 341
 342         if (err)
 343                 pr_err("IBLOCK: cache flush failed: %d\n", err);
 344
 345         if (cmd) {
 346                 if (err)
 347                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 348                 else
 349                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 350         }
 351
 352         bio_put(bio);
 353 }
 354
 355 /*
 356  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 357  * always flush the whole cache.
 358  */
 359 static sense_reason_t
 360 iblock_execute_sync_cache(struct se_cmd *cmd)
 361 {
 362         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 363         int immed = (cmd->t_task_cdb[1] & 0x2);
 364         struct bio *bio;
 365
 366         /*
 367          * If the Immediate bit is set, queue up the GOOD response
 368          * for this SYNCHRONIZE_CACHE op.
 369          */
 370         if (immed)
 371                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 372
 373         bio = bio_alloc(GFP_KERNEL, 0);
 374         bio->bi_end_io = iblock_end_io_flush;
 375         bio->bi_bdev = ib_dev->ibd_bd;
 376         if (!immed)
 377                 bio->bi_private = cmd;
 378         submit_bio(WRITE_FLUSH, bio);
 379         return 0;
 380 }
 381
 382 static sense_reason_t
 383 iblock_do_unmap(struct se_cmd *cmd, void *priv,
 384                 sector_t lba, sector_t nolb)
 385 {
 386         struct block_device *bdev = priv;
 387         int ret;
 388
 389         ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
 390         if (ret < 0) {
 391                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 392                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 393         }
 394
 395         return 0;
 396 }
 397
 398 static sense_reason_t
 399 iblock_execute_unmap(struct se_cmd *cmd)
 400 {
 401         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 402
 403         return sbc_execute_unmap(cmd, iblock_do_unmap, bdev);
 404 }
 405
 406 static sense_reason_t
 407 iblock_execute_write_same_unmap(struct se_cmd *cmd)
 408 {
 409         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 410         sector_t lba = cmd->t_task_lba;
 411         sector_t nolb = sbc_get_write_same_sectors(cmd);
 412         int ret;
 413
 414         ret = iblock_do_unmap(cmd, bdev, lba, nolb);
 415         if (ret)
 416                 return ret;
 417
 418         target_complete_cmd(cmd, GOOD);
 419         return 0;
 420 }
 421
 422 static sense_reason_t
 423 iblock_execute_write_same(struct se_cmd *cmd)
 424 {
 425         struct iblock_req *ibr;
 426         struct scatterlist *sg;
 427         struct bio *bio;
 428         struct bio_list list;
 429         sector_t block_lba = cmd->t_task_lba;
 430         sector_t sectors = sbc_get_write_same_sectors(cmd);
 431
 432         sg = &cmd->t_data_sg[0];
 433
 434         if (cmd->t_data_nents > 1 ||
 435             sg->length != cmd->se_dev->dev_attrib.block_size) {
 436                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 437                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 438                         cmd->se_dev->dev_attrib.block_size);
 439                 return TCM_INVALID_CDB_FIELD;
 440         }
 441
 442         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 443         if (!ibr)
 444                 goto fail;
 445         cmd->priv = ibr;
 446
 447         bio = iblock_get_bio(cmd, block_lba, 1);
 448         if (!bio)
 449                 goto fail_free_ibr;
 450
 451         bio_list_init(&list);
 452         bio_list_add(&list, bio);
 453
 454         atomic_set(&ibr->pending, 1);
 455
 456         while (sectors) {
 457                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 458                                 != sg->length) {
 459
 460                         bio = iblock_get_bio(cmd, block_lba, 1);
 461                         if (!bio)
 462                                 goto fail_put_bios;
 463
 464                         atomic_inc(&ibr->pending);
 465                         bio_list_add(&list, bio);
 466                 }
 467
 468                 /* Always in 512 byte units for Linux/Block */
 469                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 470                 sectors -= 1;
 471         }
 472
 473         iblock_submit_bios(&list, WRITE);
 474         return 0;
 475
 476 fail_put_bios:
 477         while ((bio = bio_list_pop(&list)))
 478                 bio_put(bio);
 479 fail_free_ibr:
 480         kfree(ibr);
 481 fail:
 482         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 483 }
 484
 485 enum {
 486         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 487 };
 488
 489 static match_table_t tokens = {
 490         {Opt_udev_path, "udev_path=%s"},
 491         {Opt_readonly, "readonly=%d"},
 492         {Opt_force, "force=%d"},
 493         {Opt_err, NULL}
 494 };
 495
 496 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 497                 const char *page, ssize_t count)
 498 {
 499         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 500         char *orig, *ptr, *arg_p, *opts;
 501         substring_t args[MAX_OPT_ARGS];
 502         int ret = 0, token;
 503         unsigned long tmp_readonly;
 504
 505         opts = kstrdup(page, GFP_KERNEL);
 506         if (!opts)
 507                 return -ENOMEM;
 508
 509         orig = opts;
 510
 511         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 512                 if (!*ptr)
 513                         continue;
 514
 515                 token = match_token(ptr, tokens, args);
 516                 switch (token) {
 517                 case Opt_udev_path:
 518                         if (ib_dev->ibd_bd) {
 519                                 pr_err("Unable to set udev_path= while"
 520                                         " ib_dev->ibd_bd exists\n");
 521                                 ret = -EEXIST;
 522                                 goto out;
 523                         }
 524                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 525                                 SE_UDEV_PATH_LEN) == 0) {
 526                                 ret = -EINVAL;
 527                                 break;
 528                         }
 529                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 530                                         ib_dev->ibd_udev_path);
 531                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 532                         break;
 533                 case Opt_readonly:
 534                         arg_p = match_strdup(&args[0]);
 535                         if (!arg_p) {
 536                                 ret = -ENOMEM;
 537                                 break;
 538                         }
 539                         ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 540                         kfree(arg_p);
 541                         if (ret < 0) {
 542                                 pr_err("strict_strtoul() failed for"
 543                                                 " readonly=\n");
 544                                 goto out;
 545                         }
 546                         ib_dev->ibd_readonly = tmp_readonly;
 547                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 548                         break;
 549                 case Opt_force:
 550                         break;
 551                 default:
 552                         break;
 553                 }
 554         }
 555
 556 out:
 557         kfree(orig);
 558         return (!ret) ? count : ret;
 559 }
 560
 561 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 562 {
 563         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 564         struct block_device *bd = ib_dev->ibd_bd;
 565         char buf[BDEVNAME_SIZE];
 566         ssize_t bl = 0;
 567
 568         if (bd)
 569                 bl += sprintf(b + bl, "iBlock device: %s",
 570                                 bdevname(bd, buf));
 571         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 572                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 573                                 ib_dev->ibd_udev_path);
 574         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 575
 576         bl += sprintf(b + bl, "        ");
 577         if (bd) {
 578                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 579                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 580                         "" : (bd->bd_holder == ib_dev) ?
 581                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 582         } else {
 583                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 584         }
 585
 586         return bl;
 587 }
 588
 589 static sense_reason_t
 590 iblock_execute_rw(struct se_cmd *cmd)
 591 {
 592         struct scatterlist *sgl = cmd->t_data_sg;
 593         u32 sgl_nents = cmd->t_data_nents;
 594         enum dma_data_direction data_direction = cmd->data_direction;
 595         struct se_device *dev = cmd->se_dev;
 596         struct iblock_req *ibr;
 597         struct bio *bio;
 598         struct bio_list list;
 599         struct scatterlist *sg;
 600         u32 sg_num = sgl_nents;
 601         sector_t block_lba;
 602         unsigned bio_cnt;
 603         int rw = 0;
 604         int i;
 605
 606         if (data_direction == DMA_TO_DEVICE) {
 607                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 608                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 609                 /*
 610                  * Force writethrough using WRITE_FUA if a volatile write cache
 611                  * is not enabled, or if initiator set the Force Unit Access bit.
 612                  */
 613                 if (q->flush_flags & REQ_FUA) {
 614                         if (cmd->se_cmd_flags & SCF_FUA)
 615                                 rw = WRITE_FUA;
 616                         else if (!(q->flush_flags & REQ_FLUSH))
 617                                 rw = WRITE_FUA;
 618                         else
 619                                 rw = WRITE;
 620                 } else {
 621                         rw = WRITE;
 622                 }
 623         } else {
 624                 rw = READ;
 625         }
 626
 627         /*
 628          * Convert the blocksize advertised to the initiator to the 512 byte
 629          * units unconditionally used by the Linux block layer.
 630          */
 631         if (dev->dev_attrib.block_size == 4096)
 632                 block_lba = (cmd->t_task_lba << 3);
 633         else if (dev->dev_attrib.block_size == 2048)
 634                 block_lba = (cmd->t_task_lba << 2);
 635         else if (dev->dev_attrib.block_size == 1024)
 636                 block_lba = (cmd->t_task_lba << 1);
 637         else if (dev->dev_attrib.block_size == 512)
 638                 block_lba = cmd->t_task_lba;
 639         else {
 640                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 641                                 " %u\n", dev->dev_attrib.block_size);
 642                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 643         }
 644
 645         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 646         if (!ibr)
 647                 goto fail;
 648         cmd->priv = ibr;
 649
 650         if (!sgl_nents) {
 651                 atomic_set(&ibr->pending, 1);
 652                 iblock_complete_cmd(cmd);
 653                 return 0;
 654         }
 655
 656         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 657         if (!bio)
 658                 goto fail_free_ibr;
 659
 660         bio_list_init(&list);
 661         bio_list_add(&list, bio);
 662
 663         atomic_set(&ibr->pending, 2);
 664         bio_cnt = 1;
 665
 666         for_each_sg(sgl, sg, sgl_nents, i) {
 667                 /*
 668                  * XXX: if the length the device accepts is shorter than the
 669                  *      length of the S/G list entry this will cause and
 670                  *      endless loop.  Better hope no driver uses huge pages.
 671                  */
 672                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 673                                 != sg->length) {
 674                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 675                                 iblock_submit_bios(&list, rw);
 676                                 bio_cnt = 0;
 677                         }
 678
 679                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 680                         if (!bio)
 681                                 goto fail_put_bios;
 682
 683                         atomic_inc(&ibr->pending);
 684                         bio_list_add(&list, bio);
 685                         bio_cnt++;
 686                 }
 687
 688                 /* Always in 512 byte units for Linux/Block */
 689                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 690                 sg_num--;
 691         }
 692
 693         iblock_submit_bios(&list, rw);
 694         iblock_complete_cmd(cmd);
 695         return 0;
 696
 697 fail_put_bios:
 698         while ((bio = bio_list_pop(&list)))
 699                 bio_put(bio);
 700 fail_free_ibr:
 701         kfree(ibr);
 702 fail:
 703         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 704 }
 705
 706 static sector_t iblock_get_blocks(struct se_device *dev)
 707 {
 708         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 709         struct block_device *bd = ib_dev->ibd_bd;
 710         struct request_queue *q = bdev_get_queue(bd);
 711
 712         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 713 }
 714
 715 static struct sbc_ops iblock_sbc_ops = {
 716         .execute_rw             = iblock_execute_rw,
 717         .execute_sync_cache     = iblock_execute_sync_cache,
 718         .execute_write_same     = iblock_execute_write_same,
 719         .execute_write_same_unmap = iblock_execute_write_same_unmap,
 720         .execute_unmap          = iblock_execute_unmap,
 721 };
 722
 723 static sense_reason_t
 724 iblock_parse_cdb(struct se_cmd *cmd)
 725 {
 726         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 727 }
 728
 729 bool iblock_get_write_cache(struct se_device *dev)
 730 {
 731         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 732         struct block_device *bd = ib_dev->ibd_bd;
 733         struct request_queue *q = bdev_get_queue(bd);
 734
 735         return q->flush_flags & REQ_FLUSH;
 736 }
 737
 738 static struct se_subsystem_api iblock_template = {
 739         .name                   = "iblock",
 740         .inquiry_prod           = "IBLOCK",
 741         .inquiry_rev            = IBLOCK_VERSION,
 742         .owner                  = THIS_MODULE,
 743         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 744         .attach_hba             = iblock_attach_hba,
 745         .detach_hba             = iblock_detach_hba,
 746         .alloc_device           = iblock_alloc_device,
 747         .configure_device       = iblock_configure_device,
 748         .free_device            = iblock_free_device,
 749         .parse_cdb              = iblock_parse_cdb,
 750         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 751         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 752         .get_device_type        = sbc_get_device_type,
 753         .get_blocks             = iblock_get_blocks,
 754         .get_write_cache        = iblock_get_write_cache,
 755 };
 756
 757 static int __init iblock_module_init(void)
 758 {
 759         return transport_subsystem_register(&iblock_template);
 760 }
 761
 762 static void __exit iblock_module_exit(void)
 763 {
 764         transport_subsystem_release(&iblock_template);
 765 }
 766
 767 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 768 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 769 MODULE_LICENSE("GPL");
 770
 771 module_init(iblock_module_init);
 772 module_exit(iblock_module_exit);