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 2003-2013 Datera, Inc.
   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_proto.h>
  39 #include <asm/unaligned.h>
  40
  41 #include <target/target_core_base.h>
  42 #include <target/target_core_backend.h>
  43
  44 #include "target_core_iblock.h"
  45
  46 #define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  47 #define IBLOCK_BIO_POOL_SIZE    128
  48
  49 static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  50 {
  51         return container_of(dev, struct iblock_dev, dev);
  52 }
  53
  54
  55 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  56 {
  57         pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  58                 " Generic Target Core Stack %s\n", hba->hba_id,
  59                 IBLOCK_VERSION, TARGET_CORE_VERSION);
  60         return 0;
  61 }
  62
  63 static void iblock_detach_hba(struct se_hba *hba)
  64 {
  65 }
  66
  67 static struct se_device *iblock_alloc_device(struct se_hba *hba, const char *name)
  68 {
  69         struct iblock_dev *ib_dev = NULL;
  70
  71         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  72         if (!ib_dev) {
  73                 pr_err("Unable to allocate struct iblock_dev\n");
  74                 return NULL;
  75         }
  76
  77         pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  78
  79         return &ib_dev->dev;
  80 }
  81
  82 static int iblock_configure_device(struct se_device *dev)
  83 {
  84         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
  85         struct request_queue *q;
  86         struct block_device *bd = NULL;
  87         struct blk_integrity *bi;
  88         fmode_t mode;
  89         int ret = -ENOMEM;
  90
  91         if (!(ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)) {
  92                 pr_err("Missing udev_path= parameters for IBLOCK\n");
  93                 return -EINVAL;
  94         }
  95
  96         ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
  97         if (!ib_dev->ibd_bio_set) {
  98                 pr_err("IBLOCK: Unable to create bioset\n");
  99                 goto out;
 100         }
 101
 102         pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 103                         ib_dev->ibd_udev_path);
 104
 105         mode = FMODE_READ|FMODE_EXCL;
 106         if (!ib_dev->ibd_readonly)
 107                 mode |= FMODE_WRITE;
 108         else
 109                 dev->dev_flags |= DF_READ_ONLY;
 110
 111         bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 112         if (IS_ERR(bd)) {
 113                 ret = PTR_ERR(bd);
 114                 goto out_free_bioset;
 115         }
 116         ib_dev->ibd_bd = bd;
 117
 118         q = bdev_get_queue(bd);
 119
 120         dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);
 121         dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);
 122         dev->dev_attrib.hw_queue_depth = q->nr_requests;
 123
 124         /*
 125          * Check if the underlying struct block_device request_queue supports
 126          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 127          * in ATA and we need to set TPE=1
 128          */
 129         if (blk_queue_discard(q)) {
 130                 dev->dev_attrib.max_unmap_lba_count =
 131                                 q->limits.max_discard_sectors;
 132
 133                 /*
 134                  * Currently hardcoded to 1 in Linux/SCSI code..
 135                  */
 136                 dev->dev_attrib.max_unmap_block_desc_count = 1;
 137                 dev->dev_attrib.unmap_granularity =
 138                                 q->limits.discard_granularity >> 9;
 139                 dev->dev_attrib.unmap_granularity_alignment =
 140                                 q->limits.discard_alignment;
 141                 dev->dev_attrib.unmap_zeroes_data =
 142                                 q->limits.discard_zeroes_data;
 143
 144                 pr_debug("IBLOCK: BLOCK Discard support available,"
 145                                 " disabled by default\n");
 146         }
 147         /*
 148          * Enable write same emulation for IBLOCK and use 0xFFFF as
 149          * the smaller WRITE_SAME(10) only has a two-byte block count.
 150          */
 151         dev->dev_attrib.max_write_same_len = 0xFFFF;
 152
 153         if (blk_queue_nonrot(q))
 154                 dev->dev_attrib.is_nonrot = 1;
 155
 156         bi = bdev_get_integrity(bd);
 157         if (bi) {
 158                 struct bio_set *bs = ib_dev->ibd_bio_set;
 159
 160                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-IP") ||
 161                     !strcmp(bi->profile->name, "T10-DIF-TYPE1-IP")) {
 162                         pr_err("IBLOCK export of blk_integrity: %s not"
 163                                " supported\n", bi->profile->name);
 164                         ret = -ENOSYS;
 165                         goto out_blkdev_put;
 166                 }
 167
 168                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-CRC")) {
 169                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
 170                 } else if (!strcmp(bi->profile->name, "T10-DIF-TYPE1-CRC")) {
 171                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
 172                 }
 173
 174                 if (dev->dev_attrib.pi_prot_type) {
 175                         if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
 176                                 pr_err("Unable to allocate bioset for PI\n");
 177                                 ret = -ENOMEM;
 178                                 goto out_blkdev_put;
 179                         }
 180                         pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
 181                                  bs->bio_integrity_pool);
 182                 }
 183                 dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
 184         }
 185
 186         return 0;
 187
 188 out_blkdev_put:
 189         blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 190 out_free_bioset:
 191         bioset_free(ib_dev->ibd_bio_set);
 192         ib_dev->ibd_bio_set = NULL;
 193 out:
 194         return ret;
 195 }
 196
 197 static void iblock_dev_call_rcu(struct rcu_head *p)
 198 {
 199         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 200         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 201
 202         kfree(ib_dev);
 203 }
 204
 205 static void iblock_free_device(struct se_device *dev)
 206 {
 207         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 208
 209         if (ib_dev->ibd_bd != NULL)
 210                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 211         if (ib_dev->ibd_bio_set != NULL)
 212                 bioset_free(ib_dev->ibd_bio_set);
 213
 214         call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
 215 }
 216
 217 static unsigned long long iblock_emulate_read_cap_with_block_size(
 218         struct se_device *dev,
 219         struct block_device *bd,
 220         struct request_queue *q)
 221 {
 222         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 223                                         bdev_logical_block_size(bd)) - 1);
 224         u32 block_size = bdev_logical_block_size(bd);
 225
 226         if (block_size == dev->dev_attrib.block_size)
 227                 return blocks_long;
 228
 229         switch (block_size) {
 230         case 4096:
 231                 switch (dev->dev_attrib.block_size) {
 232                 case 2048:
 233                         blocks_long <<= 1;
 234                         break;
 235                 case 1024:
 236                         blocks_long <<= 2;
 237                         break;
 238                 case 512:
 239                         blocks_long <<= 3;
 240                 default:
 241                         break;
 242                 }
 243                 break;
 244         case 2048:
 245                 switch (dev->dev_attrib.block_size) {
 246                 case 4096:
 247                         blocks_long >>= 1;
 248                         break;
 249                 case 1024:
 250                         blocks_long <<= 1;
 251                         break;
 252                 case 512:
 253                         blocks_long <<= 2;
 254                         break;
 255                 default:
 256                         break;
 257                 }
 258                 break;
 259         case 1024:
 260                 switch (dev->dev_attrib.block_size) {
 261                 case 4096:
 262                         blocks_long >>= 2;
 263                         break;
 264                 case 2048:
 265                         blocks_long >>= 1;
 266                         break;
 267                 case 512:
 268                         blocks_long <<= 1;
 269                         break;
 270                 default:
 271                         break;
 272                 }
 273                 break;
 274         case 512:
 275                 switch (dev->dev_attrib.block_size) {
 276                 case 4096:
 277                         blocks_long >>= 3;
 278                         break;
 279                 case 2048:
 280                         blocks_long >>= 2;
 281                         break;
 282                 case 1024:
 283                         blocks_long >>= 1;
 284                         break;
 285                 default:
 286                         break;
 287                 }
 288                 break;
 289         default:
 290                 break;
 291         }
 292
 293         return blocks_long;
 294 }
 295
 296 static void iblock_complete_cmd(struct se_cmd *cmd)
 297 {
 298         struct iblock_req *ibr = cmd->priv;
 299         u8 status;
 300
 301         if (!atomic_dec_and_test(&ibr->pending))
 302                 return;
 303
 304         if (atomic_read(&ibr->ib_bio_err_cnt))
 305                 status = SAM_STAT_CHECK_CONDITION;
 306         else
 307                 status = SAM_STAT_GOOD;
 308
 309         target_complete_cmd(cmd, status);
 310         kfree(ibr);
 311 }
 312
 313 static void iblock_bio_done(struct bio *bio)
 314 {
 315         struct se_cmd *cmd = bio->bi_private;
 316         struct iblock_req *ibr = cmd->priv;
 317
 318         if (bio->bi_error) {
 319                 pr_err("bio error: %p,  err: %d\n", bio, bio->bi_error);
 320                 /*
 321                  * Bump the ib_bio_err_cnt and release bio.
 322                  */
 323                 atomic_inc(&ibr->ib_bio_err_cnt);
 324                 smp_mb__after_atomic();
 325         }
 326
 327         bio_put(bio);
 328
 329         iblock_complete_cmd(cmd);
 330 }
 331
 332 static struct bio *
 333 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 334 {
 335         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 336         struct bio *bio;
 337
 338         /*
 339          * Only allocate as many vector entries as the bio code allows us to,
 340          * we'll loop later on until we have handled the whole request.
 341          */
 342         if (sg_num > BIO_MAX_PAGES)
 343                 sg_num = BIO_MAX_PAGES;
 344
 345         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 346         if (!bio) {
 347                 pr_err("Unable to allocate memory for bio\n");
 348                 return NULL;
 349         }
 350
 351         bio->bi_bdev = ib_dev->ibd_bd;
 352         bio->bi_private = cmd;
 353         bio->bi_end_io = &iblock_bio_done;
 354         bio->bi_iter.bi_sector = lba;
 355
 356         return bio;
 357 }
 358
 359 static void iblock_submit_bios(struct bio_list *list, int rw)
 360 {
 361         struct blk_plug plug;
 362         struct bio *bio;
 363
 364         blk_start_plug(&plug);
 365         while ((bio = bio_list_pop(list)))
 366                 submit_bio(rw, bio);
 367         blk_finish_plug(&plug);
 368 }
 369
 370 static void iblock_end_io_flush(struct bio *bio)
 371 {
 372         struct se_cmd *cmd = bio->bi_private;
 373
 374         if (bio->bi_error)
 375                 pr_err("IBLOCK: cache flush failed: %d\n", bio->bi_error);
 376
 377         if (cmd) {
 378                 if (bio->bi_error)
 379                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 380                 else
 381                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 382         }
 383
 384         bio_put(bio);
 385 }
 386
 387 /*
 388  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 389  * always flush the whole cache.
 390  */
 391 static sense_reason_t
 392 iblock_execute_sync_cache(struct se_cmd *cmd)
 393 {
 394         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 395         int immed = (cmd->t_task_cdb[1] & 0x2);
 396         struct bio *bio;
 397
 398         /*
 399          * If the Immediate bit is set, queue up the GOOD response
 400          * for this SYNCHRONIZE_CACHE op.
 401          */
 402         if (immed)
 403                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 404
 405         bio = bio_alloc(GFP_KERNEL, 0);
 406         bio->bi_end_io = iblock_end_io_flush;
 407         bio->bi_bdev = ib_dev->ibd_bd;
 408         if (!immed)
 409                 bio->bi_private = cmd;
 410         submit_bio(WRITE_FLUSH, bio);
 411         return 0;
 412 }
 413
 414 static sense_reason_t
 415 iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 416 {
 417         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 418         int ret;
 419
 420         ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
 421         if (ret < 0) {
 422                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 423                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 424         }
 425
 426         return 0;
 427 }
 428
 429 static sense_reason_t
 430 iblock_execute_write_same(struct se_cmd *cmd)
 431 {
 432         struct iblock_req *ibr;
 433         struct scatterlist *sg;
 434         struct bio *bio;
 435         struct bio_list list;
 436         sector_t block_lba = cmd->t_task_lba;
 437         sector_t sectors = sbc_get_write_same_sectors(cmd);
 438
 439         if (cmd->prot_op) {
 440                 pr_err("WRITE_SAME: Protection information with IBLOCK"
 441                        " backends not supported\n");
 442                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 443         }
 444         sg = &cmd->t_data_sg[0];
 445
 446         if (cmd->t_data_nents > 1 ||
 447             sg->length != cmd->se_dev->dev_attrib.block_size) {
 448                 pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 449                         " block_size: %u\n", cmd->t_data_nents, sg->length,
 450                         cmd->se_dev->dev_attrib.block_size);
 451                 return TCM_INVALID_CDB_FIELD;
 452         }
 453
 454         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 455         if (!ibr)
 456                 goto fail;
 457         cmd->priv = ibr;
 458
 459         bio = iblock_get_bio(cmd, block_lba, 1);
 460         if (!bio)
 461                 goto fail_free_ibr;
 462
 463         bio_list_init(&list);
 464         bio_list_add(&list, bio);
 465
 466         atomic_set(&ibr->pending, 1);
 467
 468         while (sectors) {
 469                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 470                                 != sg->length) {
 471
 472                         bio = iblock_get_bio(cmd, block_lba, 1);
 473                         if (!bio)
 474                                 goto fail_put_bios;
 475
 476                         atomic_inc(&ibr->pending);
 477                         bio_list_add(&list, bio);
 478                 }
 479
 480                 /* Always in 512 byte units for Linux/Block */
 481                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 482                 sectors -= 1;
 483         }
 484
 485         iblock_submit_bios(&list, WRITE);
 486         return 0;
 487
 488 fail_put_bios:
 489         while ((bio = bio_list_pop(&list)))
 490                 bio_put(bio);
 491 fail_free_ibr:
 492         kfree(ibr);
 493 fail:
 494         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 495 }
 496
 497 enum {
 498         Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 499 };
 500
 501 static match_table_t tokens = {
 502         {Opt_udev_path, "udev_path=%s"},
 503         {Opt_readonly, "readonly=%d"},
 504         {Opt_force, "force=%d"},
 505         {Opt_err, NULL}
 506 };
 507
 508 static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 509                 const char *page, ssize_t count)
 510 {
 511         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 512         char *orig, *ptr, *arg_p, *opts;
 513         substring_t args[MAX_OPT_ARGS];
 514         int ret = 0, token;
 515         unsigned long tmp_readonly;
 516
 517         opts = kstrdup(page, GFP_KERNEL);
 518         if (!opts)
 519                 return -ENOMEM;
 520
 521         orig = opts;
 522
 523         while ((ptr = strsep(&opts, ",\n")) != NULL) {
 524                 if (!*ptr)
 525                         continue;
 526
 527                 token = match_token(ptr, tokens, args);
 528                 switch (token) {
 529                 case Opt_udev_path:
 530                         if (ib_dev->ibd_bd) {
 531                                 pr_err("Unable to set udev_path= while"
 532                                         " ib_dev->ibd_bd exists\n");
 533                                 ret = -EEXIST;
 534                                 goto out;
 535                         }
 536                         if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 537                                 SE_UDEV_PATH_LEN) == 0) {
 538                                 ret = -EINVAL;
 539                                 break;
 540                         }
 541                         pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 542                                         ib_dev->ibd_udev_path);
 543                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 544                         break;
 545                 case Opt_readonly:
 546                         arg_p = match_strdup(&args[0]);
 547                         if (!arg_p) {
 548                                 ret = -ENOMEM;
 549                                 break;
 550                         }
 551                         ret = kstrtoul(arg_p, 0, &tmp_readonly);
 552                         kfree(arg_p);
 553                         if (ret < 0) {
 554                                 pr_err("kstrtoul() failed for"
 555                                                 " readonly=\n");
 556                                 goto out;
 557                         }
 558                         ib_dev->ibd_readonly = tmp_readonly;
 559                         pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 560                         break;
 561                 case Opt_force:
 562                         break;
 563                 default:
 564                         break;
 565                 }
 566         }
 567
 568 out:
 569         kfree(orig);
 570         return (!ret) ? count : ret;
 571 }
 572
 573 static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 574 {
 575         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 576         struct block_device *bd = ib_dev->ibd_bd;
 577         char buf[BDEVNAME_SIZE];
 578         ssize_t bl = 0;
 579
 580         if (bd)
 581                 bl += sprintf(b + bl, "iBlock device: %s",
 582                                 bdevname(bd, buf));
 583         if (ib_dev->ibd_flags & IBDF_HAS_UDEV_PATH)
 584                 bl += sprintf(b + bl, "  UDEV PATH: %s",
 585                                 ib_dev->ibd_udev_path);
 586         bl += sprintf(b + bl, "  readonly: %d\n", ib_dev->ibd_readonly);
 587
 588         bl += sprintf(b + bl, "        ");
 589         if (bd) {
 590                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 591                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 592                         "" : (bd->bd_holder == ib_dev) ?
 593                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 594         } else {
 595                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 596         }
 597
 598         return bl;
 599 }
 600
 601 static int
 602 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
 603 {
 604         struct se_device *dev = cmd->se_dev;
 605         struct blk_integrity *bi;
 606         struct bio_integrity_payload *bip;
 607         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 608         struct scatterlist *sg;
 609         int i, rc;
 610
 611         bi = bdev_get_integrity(ib_dev->ibd_bd);
 612         if (!bi) {
 613                 pr_err("Unable to locate bio_integrity\n");
 614                 return -ENODEV;
 615         }
 616
 617         bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
 618         if (IS_ERR(bip)) {
 619                 pr_err("Unable to allocate bio_integrity_payload\n");
 620                 return PTR_ERR(bip);
 621         }
 622
 623         bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
 624                          dev->prot_length;
 625         bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 626
 627         pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 628                  (unsigned long long)bip->bip_iter.bi_sector);
 629
 630         for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
 631
 632                 rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
 633                                             sg->offset);
 634                 if (rc != sg->length) {
 635                         pr_err("bio_integrity_add_page() failed; %d\n", rc);
 636                         return -ENOMEM;
 637                 }
 638
 639                 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
 640                          sg_page(sg), sg->length, sg->offset);
 641         }
 642
 643         return 0;
 644 }
 645
 646 static sense_reason_t
 647 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 648                   enum dma_data_direction data_direction)
 649 {
 650         struct se_device *dev = cmd->se_dev;
 651         struct iblock_req *ibr;
 652         struct bio *bio, *bio_start;
 653         struct bio_list list;
 654         struct scatterlist *sg;
 655         u32 sg_num = sgl_nents;
 656         sector_t block_lba;
 657         unsigned bio_cnt;
 658         int rw = 0;
 659         int i;
 660
 661         if (data_direction == DMA_TO_DEVICE) {
 662                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 663                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 664                 /*
 665                  * Force writethrough using WRITE_FUA if a volatile write cache
 666                  * is not enabled, or if initiator set the Force Unit Access bit.
 667                  */
 668                 if (q->flush_flags & REQ_FUA) {
 669                         if (cmd->se_cmd_flags & SCF_FUA)
 670                                 rw = WRITE_FUA;
 671                         else if (!(q->flush_flags & REQ_FLUSH))
 672                                 rw = WRITE_FUA;
 673                         else
 674                                 rw = WRITE;
 675                 } else {
 676                         rw = WRITE;
 677                 }
 678         } else {
 679                 rw = READ;
 680         }
 681
 682         /*
 683          * Convert the blocksize advertised to the initiator to the 512 byte
 684          * units unconditionally used by the Linux block layer.
 685          */
 686         if (dev->dev_attrib.block_size == 4096)
 687                 block_lba = (cmd->t_task_lba << 3);
 688         else if (dev->dev_attrib.block_size == 2048)
 689                 block_lba = (cmd->t_task_lba << 2);
 690         else if (dev->dev_attrib.block_size == 1024)
 691                 block_lba = (cmd->t_task_lba << 1);
 692         else if (dev->dev_attrib.block_size == 512)
 693                 block_lba = cmd->t_task_lba;
 694         else {
 695                 pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 696                                 " %u\n", dev->dev_attrib.block_size);
 697                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 698         }
 699
 700         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 701         if (!ibr)
 702                 goto fail;
 703         cmd->priv = ibr;
 704
 705         if (!sgl_nents) {
 706                 atomic_set(&ibr->pending, 1);
 707                 iblock_complete_cmd(cmd);
 708                 return 0;
 709         }
 710
 711         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 712         if (!bio)
 713                 goto fail_free_ibr;
 714
 715         bio_start = bio;
 716         bio_list_init(&list);
 717         bio_list_add(&list, bio);
 718
 719         atomic_set(&ibr->pending, 2);
 720         bio_cnt = 1;
 721
 722         for_each_sg(sgl, sg, sgl_nents, i) {
 723                 /*
 724                  * XXX: if the length the device accepts is shorter than the
 725                  *      length of the S/G list entry this will cause and
 726                  *      endless loop.  Better hope no driver uses huge pages.
 727                  */
 728                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 729                                 != sg->length) {
 730                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 731                                 iblock_submit_bios(&list, rw);
 732                                 bio_cnt = 0;
 733                         }
 734
 735                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 736                         if (!bio)
 737                                 goto fail_put_bios;
 738
 739                         atomic_inc(&ibr->pending);
 740                         bio_list_add(&list, bio);
 741                         bio_cnt++;
 742                 }
 743
 744                 /* Always in 512 byte units for Linux/Block */
 745                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 746                 sg_num--;
 747         }
 748
 749         if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
 750                 int rc = iblock_alloc_bip(cmd, bio_start);
 751                 if (rc)
 752                         goto fail_put_bios;
 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 sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
 778 {
 779         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 780         struct block_device *bd = ib_dev->ibd_bd;
 781         int ret;
 782
 783         ret = bdev_alignment_offset(bd);
 784         if (ret == -1)
 785                 return 0;
 786
 787         /* convert offset-bytes to offset-lbas */
 788         return ret / bdev_logical_block_size(bd);
 789 }
 790
 791 static unsigned int iblock_get_lbppbe(struct se_device *dev)
 792 {
 793         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 794         struct block_device *bd = ib_dev->ibd_bd;
 795         int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
 796
 797         return ilog2(logs_per_phys);
 798 }
 799
 800 static unsigned int iblock_get_io_min(struct se_device *dev)
 801 {
 802         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 803         struct block_device *bd = ib_dev->ibd_bd;
 804
 805         return bdev_io_min(bd);
 806 }
 807
 808 static unsigned int iblock_get_io_opt(struct se_device *dev)
 809 {
 810         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 811         struct block_device *bd = ib_dev->ibd_bd;
 812
 813         return bdev_io_opt(bd);
 814 }
 815
 816 static struct sbc_ops iblock_sbc_ops = {
 817         .execute_rw             = iblock_execute_rw,
 818         .execute_sync_cache     = iblock_execute_sync_cache,
 819         .execute_write_same     = iblock_execute_write_same,
 820         .execute_unmap          = iblock_execute_unmap,
 821 };
 822
 823 static sense_reason_t
 824 iblock_parse_cdb(struct se_cmd *cmd)
 825 {
 826         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 827 }
 828
 829 static bool iblock_get_write_cache(struct se_device *dev)
 830 {
 831         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 832         struct block_device *bd = ib_dev->ibd_bd;
 833         struct request_queue *q = bdev_get_queue(bd);
 834
 835         return q->flush_flags & REQ_FLUSH;
 836 }
 837
 838 static const struct target_backend_ops iblock_ops = {
 839         .name                   = "iblock",
 840         .inquiry_prod           = "IBLOCK",
 841         .inquiry_rev            = IBLOCK_VERSION,
 842         .owner                  = THIS_MODULE,
 843         .attach_hba             = iblock_attach_hba,
 844         .detach_hba             = iblock_detach_hba,
 845         .alloc_device           = iblock_alloc_device,
 846         .configure_device       = iblock_configure_device,
 847         .free_device            = iblock_free_device,
 848         .parse_cdb              = iblock_parse_cdb,
 849         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 850         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 851         .get_device_type        = sbc_get_device_type,
 852         .get_blocks             = iblock_get_blocks,
 853         .get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
 854         .get_lbppbe             = iblock_get_lbppbe,
 855         .get_io_min             = iblock_get_io_min,
 856         .get_io_opt             = iblock_get_io_opt,
 857         .get_write_cache        = iblock_get_write_cache,
 858         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 859 };
 860
 861 static int __init iblock_module_init(void)
 862 {
 863         return transport_backend_register(&iblock_ops);
 864 }
 865
 866 static void __exit iblock_module_exit(void)
 867 {
 868         target_backend_unregister(&iblock_ops);
 869 }
 870
 871 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 872 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 873 MODULE_LICENSE("GPL");
 874
 875 module_init(iblock_module_init);
 876 module_exit(iblock_module_exit);