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 = UINT_MAX;
 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_execute_unmap(struct se_cmd *cmd)
 384 {
 385         struct se_device *dev = cmd->se_dev;
 386         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 387         unsigned char *buf, *ptr = NULL;
 388         sector_t lba;
 389         int size;
 390         u32 range;
 391         sense_reason_t ret = 0;
 392         int dl, bd_dl, err;
 393
 394         /* We never set ANC_SUP */
 395         if (cmd->t_task_cdb[1])
 396                 return TCM_INVALID_CDB_FIELD;
 397
 398         if (cmd->data_length == 0) {
 399                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 400                 return 0;
 401         }
 402
 403         if (cmd->data_length < 8) {
 404                 pr_warn("UNMAP parameter list length %u too small\n",
 405                         cmd->data_length);
 406                 return TCM_PARAMETER_LIST_LENGTH_ERROR;
 407         }
 408
 409         buf = transport_kmap_data_sg(cmd);
 410         if (!buf)
 411                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 412
 413         dl = get_unaligned_be16(&buf[0]);
 414         bd_dl = get_unaligned_be16(&buf[2]);
 415
 416         size = cmd->data_length - 8;
 417         if (bd_dl > size)
 418                 pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
 419                         cmd->data_length, bd_dl);
 420         else
 421                 size = bd_dl;
 422
 423         if (size / 16 > dev->dev_attrib.max_unmap_block_desc_count) {
 424                 ret = TCM_INVALID_PARAMETER_LIST;
 425                 goto err;
 426         }
 427
 428         /* First UNMAP block descriptor starts at 8 byte offset */
 429         ptr = &buf[8];
 430         pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
 431                 " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
 432
 433         while (size >= 16) {
 434                 lba = get_unaligned_be64(&ptr[0]);
 435                 range = get_unaligned_be32(&ptr[8]);
 436                 pr_debug("UNMAP: Using lba: %llu and range: %u\n",
 437                                  (unsigned long long)lba, range);
 438
 439                 if (range > dev->dev_attrib.max_unmap_lba_count) {
 440                         ret = TCM_INVALID_PARAMETER_LIST;
 441                         goto err;
 442                 }
 443
 444                 if (lba + range > dev->transport->get_blocks(dev) + 1) {
 445                         ret = TCM_ADDRESS_OUT_OF_RANGE;
 446                         goto err;
 447                 }
 448
 449                 err = blkdev_issue_discard(ib_dev->ibd_bd, lba, range,
 450                                            GFP_KERNEL, 0);
 451                 if (err < 0) {
 452                         pr_err("blkdev_issue_discard() failed: %d\n",
 453                                         err);
 454                         ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 455                         goto err;
 456                 }
 457
 458                 ptr += 16;
 459                 size -= 16;
 460         }
 461
 462 err:
 463         transport_kunmap_data_sg(cmd);
 464         if (!ret)
 465                 target_complete_cmd(cmd, GOOD);
 466         return ret;
 467 }
 468
 469 static sense_reason_t
 470 iblock_execute_write_same_unmap(struct se_cmd *cmd)
 471 {
 472         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 473         int rc;
 474
 475         rc = blkdev_issue_discard(ib_dev->ibd_bd, cmd->t_task_lba,
 476                         sbc_get_write_same_sectors(cmd), GFP_KERNEL, 0);
 477         if (rc < 0) {
 478                 pr_warn("blkdev_issue_discard() failed: %d\n", rc);
 479                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 480         }
 481
 482         target_complete_cmd(cmd, GOOD);
 483         return 0;
 484 }
 485
 486 static sense_reason_t
 487 iblock_execute_write_same(struct se_cmd *cmd)
 488 {
 489         struct iblock_req *ibr;
 490         struct scatterlist *sg;
 491         struct bio *bio;
 492         struct bio_list list;
 493         sector_t block_lba = cmd->t_task_lba;
 494         sector_t sectors = sbc_get_write_same_sectors(cmd);
 495
 496         sg = &cmd->t_data_sg[0];
 497
 498         if (cmd->t_data_nents > 1 ||
 499             sg->length != cmd->se_dev->dev_attrib.block_size) {
 500                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 501                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 502                         cmd->se_dev->dev_attrib.block_size);
 503                 return TCM_INVALID_CDB_FIELD;
 504         }
 505
 506         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 507         if (!ibr)
 508                 goto fail;
 509         cmd->priv = ibr;
 510
 511         bio = iblock_get_bio(cmd, block_lba, 1);
 512         if (!bio)
 513                 goto fail_free_ibr;
 514
 515         bio_list_init(&list);
 516         bio_list_add(&list, bio);
 517
 518         atomic_set(&ibr->pending, 1);
 519
 520         while (sectors) {
 521                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 522                                 != sg->length) {
 523
 524                         bio = iblock_get_bio(cmd, block_lba, 1);
 525                         if (!bio)
 526                                 goto fail_put_bios;
 527
 528                         atomic_inc(&ibr->pending);
 529                         bio_list_add(&list, bio);
 530                 }
 531
 532                 /* Always in 512 byte units for Linux/Block */
 533                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 534                 sectors -= 1;
 535         }
 536
 537         iblock_submit_bios(&list, WRITE);
 538         return 0;
 539
 540 fail_put_bios:
 541         while ((bio = bio_list_pop(&list)))
 542                 bio_put(bio);
 543 fail_free_ibr:
 544         kfree(ibr);
 545 fail:
 546         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 547 }
 548
 549 enum {
 550         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 551 };
 552
 553 static match_table_t tokens = {
 554         {Opt_udev_path, "udev_path=%s"},
 555         {Opt_readonly, "readonly=%d"},
 556         {Opt_force, "force=%d"},
 557         {Opt_err, NULL}
 558 };
 559
 560 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 561                 const char *page, ssize_t count)
 562 {
 563         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 564         char *orig, *ptr, *arg_p, *opts;
 565         substring_t args[MAX_OPT_ARGS];
 566         int ret = 0, token;
 567         unsigned long tmp_readonly;
 568
 569         opts = kstrdup(page, GFP_KERNEL);
 570         if (!opts)
 571                 return -ENOMEM;
 572
 573         orig = opts;
 574
 575         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 576                 if (!*ptr)
 577                         continue;
 578
 579                 token = match_token(ptr, tokens, args);
 580                 switch (token) {
 581                 case Opt_udev_path:
 582                         if (ib_dev->ibd_bd) {
 583                                 pr_err("Unable to set udev_path= while"
 584                                         " ib_dev->ibd_bd exists\n");
 585                                 ret = -EEXIST;
 586                                 goto out;
 587                         }
 588                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 589                                 SE_UDEV_PATH_LEN) == 0) {
 590                                 ret = -EINVAL;
 591                                 break;
 592                         }
 593                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 594                                         ib_dev->ibd_udev_path);
 595                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 596                         break;
 597                 case Opt_readonly:
 598                         arg_p = match_strdup(&args[0]);
 599                         if (!arg_p) {
 600                                 ret = -ENOMEM;
 601                                 break;
 602                         }
 603                         ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 604                         kfree(arg_p);
 605                         if (ret < 0) {
 606                                 pr_err("strict_strtoul() failed for"
 607                                                 " readonly=\n");
 608                                 goto out;
 609                         }
 610                         ib_dev->ibd_readonly = tmp_readonly;
 611                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 612                         break;
 613                 case Opt_force:
 614                         break;
 615                 default:
 616                         break;
 617                 }
 618         }
 619
 620 out:
 621         kfree(orig);
 622         return (!ret) ? count : ret;
 623 }
 624
 625 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 626 {
 627         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 628         struct block_device *bd = ib_dev->ibd_bd;
 629         char buf[BDEVNAME_SIZE];
 630         ssize_t bl = 0;
 631
 632         if (bd)
 633                 bl += sprintf(b + bl, "iBlock device: %s",
 634                                 bdevname(bd, buf));
 635         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 636                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 637                                 ib_dev->ibd_udev_path);
 638         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 639
 640         bl += sprintf(b + bl, "        ");
 641         if (bd) {
 642                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 643                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 644                         "" : (bd->bd_holder == ib_dev) ?
 645                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 646         } else {
 647                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 648         }
 649
 650         return bl;
 651 }
 652
 653 static sense_reason_t
 654 iblock_execute_rw(struct se_cmd *cmd)
 655 {
 656         struct scatterlist *sgl = cmd->t_data_sg;
 657         u32 sgl_nents = cmd->t_data_nents;
 658         enum dma_data_direction data_direction = cmd->data_direction;
 659         struct se_device *dev = cmd->se_dev;
 660         struct iblock_req *ibr;
 661         struct bio *bio;
 662         struct bio_list list;
 663         struct scatterlist *sg;
 664         u32 sg_num = sgl_nents;
 665         sector_t block_lba;
 666         unsigned bio_cnt;
 667         int rw = 0;
 668         int i;
 669
 670         if (data_direction == DMA_TO_DEVICE) {
 671                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 672                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 673                 /*
 674                  * Force writethrough using WRITE_FUA if a volatile write cache
 675                  * is not enabled, or if initiator set the Force Unit Access bit.
 676                  */
 677                 if (q->flush_flags & REQ_FUA) {
 678                         if (cmd->se_cmd_flags & SCF_FUA)
 679                                 rw = WRITE_FUA;
 680                         else if (!(q->flush_flags & REQ_FLUSH))
 681                                 rw = WRITE_FUA;
 682                 } else {
 683                         rw = WRITE;
 684                 }
 685         } else {
 686                 rw = READ;
 687         }
 688
 689         /*
 690          * Convert the blocksize advertised to the initiator to the 512 byte
 691          * units unconditionally used by the Linux block layer.
 692          */
 693         if (dev->dev_attrib.block_size == 4096)
 694                 block_lba = (cmd->t_task_lba << 3);
 695         else if (dev->dev_attrib.block_size == 2048)
 696                 block_lba = (cmd->t_task_lba << 2);
 697         else if (dev->dev_attrib.block_size == 1024)
 698                 block_lba = (cmd->t_task_lba << 1);
 699         else if (dev->dev_attrib.block_size == 512)
 700                 block_lba = cmd->t_task_lba;
 701         else {
 702                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 703                                 " %u\n", dev->dev_attrib.block_size);
 704                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 705         }
 706
 707         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 708         if (!ibr)
 709                 goto fail;
 710         cmd->priv = ibr;
 711
 712         if (!sgl_nents) {
 713                 atomic_set(&ibr->pending, 1);
 714                 iblock_complete_cmd(cmd);
 715                 return 0;
 716         }
 717
 718         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 719         if (!bio)
 720                 goto fail_free_ibr;
 721
 722         bio_list_init(&list);
 723         bio_list_add(&list, bio);
 724
 725         atomic_set(&ibr->pending, 2);
 726         bio_cnt = 1;
 727
 728         for_each_sg(sgl, sg, sgl_nents, i) {
 729                 /*
 730                  * XXX: if the length the device accepts is shorter than the
 731                  *      length of the S/G list entry this will cause and
 732                  *      endless loop.  Better hope no driver uses huge pages.
 733                  */
 734                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 735                                 != sg->length) {
 736                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 737                                 iblock_submit_bios(&list, rw);
 738                                 bio_cnt = 0;
 739                         }
 740
 741                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 742                         if (!bio)
 743                                 goto fail_put_bios;
 744
 745                         atomic_inc(&ibr->pending);
 746                         bio_list_add(&list, bio);
 747                         bio_cnt++;
 748                 }
 749
 750                 /* Always in 512 byte units for Linux/Block */
 751                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 752                 sg_num--;
 753         }
 754
 755         iblock_submit_bios(&list, rw);
 756         iblock_complete_cmd(cmd);
 757         return 0;
 758
 759 fail_put_bios:
 760         while ((bio = bio_list_pop(&list)))
 761                 bio_put(bio);
 762 fail_free_ibr:
 763         kfree(ibr);
 764 fail:
 765         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 766 }
 767
 768 static sector_t iblock_get_blocks(struct se_device *dev)
 769 {
 770         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 771         struct block_device *bd = ib_dev->ibd_bd;
 772         struct request_queue *q = bdev_get_queue(bd);
 773
 774         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 775 }
 776
 777 static struct sbc_ops iblock_sbc_ops = {
 778         .execute_rw             = iblock_execute_rw,
 779         .execute_sync_cache     = iblock_execute_sync_cache,
 780         .execute_write_same     = iblock_execute_write_same,
 781         .execute_write_same_unmap = iblock_execute_write_same_unmap,
 782         .execute_unmap          = iblock_execute_unmap,
 783 };
 784
 785 static sense_reason_t
 786 iblock_parse_cdb(struct se_cmd *cmd)
 787 {
 788         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 789 }
 790
 791 bool iblock_get_write_cache(struct se_device *dev)
 792 {
 793         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 794         struct block_device *bd = ib_dev->ibd_bd;
 795         struct request_queue *q = bdev_get_queue(bd);
 796
 797         return q->flush_flags & REQ_FLUSH;
 798 }
 799
 800 static struct se_subsystem_api iblock_template = {
 801         .name                   = "iblock",
 802         .inquiry_prod           = "IBLOCK",
 803         .inquiry_rev            = IBLOCK_VERSION,
 804         .owner                  = THIS_MODULE,
 805         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 806         .attach_hba             = iblock_attach_hba,
 807         .detach_hba             = iblock_detach_hba,
 808         .alloc_device           = iblock_alloc_device,
 809         .configure_device       = iblock_configure_device,
 810         .free_device            = iblock_free_device,
 811         .parse_cdb              = iblock_parse_cdb,
 812         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 813         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 814         .get_device_type        = sbc_get_device_type,
 815         .get_blocks             = iblock_get_blocks,
 816         .get_write_cache        = iblock_get_write_cache,
 817 };
 818
 819 static int __init iblock_module_init(void)
 820 {
 821         return transport_subsystem_register(&iblock_template);
 822 }
 823
 824 static void __exit iblock_module_exit(void)
 825 {
 826         transport_subsystem_release(&iblock_template);
 827 }
 828
 829 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 830 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 831 MODULE_LICENSE("GPL");
 832
 833 module_init(iblock_module_init);
 834 module_exit(iblock_module_exit);