kernel/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         if (target_configure_unmap_from_queue(&dev->dev_attrib, q,
 125                                               dev->dev_attrib.hw_block_size))
 126                 pr_debug("IBLOCK: BLOCK Discard support available,"
 127                          " disabled by default\n");
 128
 129         /*
 130          * Enable write same emulation for IBLOCK and use 0xFFFF as
 131          * the smaller WRITE_SAME(10) only has a two-byte block count.
 132          */
 133         dev->dev_attrib.max_write_same_len = 0xFFFF;
 134
 135         if (blk_queue_nonrot(q))
 136                 dev->dev_attrib.is_nonrot = 1;
 137
 138         bi = bdev_get_integrity(bd);
 139         if (bi) {
 140                 struct bio_set *bs = ib_dev->ibd_bio_set;
 141
 142                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-IP") ||
 143                     !strcmp(bi->profile->name, "T10-DIF-TYPE1-IP")) {
 144                         pr_err("IBLOCK export of blk_integrity: %s not"
 145                                " supported\n", bi->profile->name);
 146                         ret = -ENOSYS;
 147                         goto out_blkdev_put;
 148                 }
 149
 150                 if (!strcmp(bi->profile->name, "T10-DIF-TYPE3-CRC")) {
 151                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE3_PROT;
 152                 } else if (!strcmp(bi->profile->name, "T10-DIF-TYPE1-CRC")) {
 153                         dev->dev_attrib.pi_prot_type = TARGET_DIF_TYPE1_PROT;
 154                 }
 155
 156                 if (dev->dev_attrib.pi_prot_type) {
 157                         if (bioset_integrity_create(bs, IBLOCK_BIO_POOL_SIZE) < 0) {
 158                                 pr_err("Unable to allocate bioset for PI\n");
 159                                 ret = -ENOMEM;
 160                                 goto out_blkdev_put;
 161                         }
 162                         pr_debug("IBLOCK setup BIP bs->bio_integrity_pool: %p\n",
 163                                  bs->bio_integrity_pool);
 164                 }
 165                 dev->dev_attrib.hw_pi_prot_type = dev->dev_attrib.pi_prot_type;
 166         }
 167
 168         return 0;
 169
 170 out_blkdev_put:
 171         blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 172 out_free_bioset:
 173         bioset_free(ib_dev->ibd_bio_set);
 174         ib_dev->ibd_bio_set = NULL;
 175 out:
 176         return ret;
 177 }
 178
 179 static void iblock_dev_call_rcu(struct rcu_head *p)
 180 {
 181         struct se_device *dev = container_of(p, struct se_device, rcu_head);
 182         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 183
 184         kfree(ib_dev);
 185 }
 186
 187 static void iblock_free_device(struct se_device *dev)
 188 {
 189         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 190
 191         if (ib_dev->ibd_bd != NULL)
 192                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 193         if (ib_dev->ibd_bio_set != NULL)
 194                 bioset_free(ib_dev->ibd_bio_set);
 195
 196         call_rcu(&dev->rcu_head, iblock_dev_call_rcu);
 197 }
 198
 199 static unsigned long long iblock_emulate_read_cap_with_block_size(
 200         struct se_device *dev,
 201         struct block_device *bd,
 202         struct request_queue *q)
 203 {
 204         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 205                                         bdev_logical_block_size(bd)) - 1);
 206         u32 block_size = bdev_logical_block_size(bd);
 207
 208         if (block_size == dev->dev_attrib.block_size)
 209                 return blocks_long;
 210
 211         switch (block_size) {
 212         case 4096:
 213                 switch (dev->dev_attrib.block_size) {
 214                 case 2048:
 215                         blocks_long <<= 1;
 216                         break;
 217                 case 1024:
 218                         blocks_long <<= 2;
 219                         break;
 220                 case 512:
 221                         blocks_long <<= 3;
 222                 default:
 223                         break;
 224                 }
 225                 break;
 226         case 2048:
 227                 switch (dev->dev_attrib.block_size) {
 228                 case 4096:
 229                         blocks_long >>= 1;
 230                         break;
 231                 case 1024:
 232                         blocks_long <<= 1;
 233                         break;
 234                 case 512:
 235                         blocks_long <<= 2;
 236                         break;
 237                 default:
 238                         break;
 239                 }
 240                 break;
 241         case 1024:
 242                 switch (dev->dev_attrib.block_size) {
 243                 case 4096:
 244                         blocks_long >>= 2;
 245                         break;
 246                 case 2048:
 247                         blocks_long >>= 1;
 248                         break;
 249                 case 512:
 250                         blocks_long <<= 1;
 251                         break;
 252                 default:
 253                         break;
 254                 }
 255                 break;
 256         case 512:
 257                 switch (dev->dev_attrib.block_size) {
 258                 case 4096:
 259                         blocks_long >>= 3;
 260                         break;
 261                 case 2048:
 262                         blocks_long >>= 2;
 263                         break;
 264                 case 1024:
 265                         blocks_long >>= 1;
 266                         break;
 267                 default:
 268                         break;
 269                 }
 270                 break;
 271         default:
 272                 break;
 273         }
 274
 275         return blocks_long;
 276 }
 277
 278 static void iblock_complete_cmd(struct se_cmd *cmd)
 279 {
 280         struct iblock_req *ibr = cmd->priv;
 281         u8 status;
 282
 283         if (!atomic_dec_and_test(&ibr->pending))
 284                 return;
 285
 286         if (atomic_read(&ibr->ib_bio_err_cnt))
 287                 status = SAM_STAT_CHECK_CONDITION;
 288         else
 289                 status = SAM_STAT_GOOD;
 290
 291         target_complete_cmd(cmd, status);
 292         kfree(ibr);
 293 }
 294
 295 static void iblock_bio_done(struct bio *bio)
 296 {
 297         struct se_cmd *cmd = bio->bi_private;
 298         struct iblock_req *ibr = cmd->priv;
 299
 300         if (bio->bi_error) {
 301                 pr_err("bio error: %p,  err: %d\n", bio, bio->bi_error);
 302                 /*
 303                  * Bump the ib_bio_err_cnt and release bio.
 304                  */
 305                 atomic_inc(&ibr->ib_bio_err_cnt);
 306                 smp_mb__after_atomic();
 307         }
 308
 309         bio_put(bio);
 310
 311         iblock_complete_cmd(cmd);
 312 }
 313
 314 static struct bio *
 315 iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 316 {
 317         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 318         struct bio *bio;
 319
 320         /*
 321          * Only allocate as many vector entries as the bio code allows us to,
 322          * we'll loop later on until we have handled the whole request.
 323          */
 324         if (sg_num > BIO_MAX_PAGES)
 325                 sg_num = BIO_MAX_PAGES;
 326
 327         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 328         if (!bio) {
 329                 pr_err("Unable to allocate memory for bio\n");
 330                 return NULL;
 331         }
 332
 333         bio->bi_bdev = ib_dev->ibd_bd;
 334         bio->bi_private = cmd;
 335         bio->bi_end_io = &iblock_bio_done;
 336         bio->bi_iter.bi_sector = lba;
 337
 338         return bio;
 339 }
 340
 341 static void iblock_submit_bios(struct bio_list *list, int rw)
 342 {
 343         struct blk_plug plug;
 344         struct bio *bio;
 345
 346         blk_start_plug(&plug);
 347         while ((bio = bio_list_pop(list)))
 348                 submit_bio(rw, bio);
 349         blk_finish_plug(&plug);
 350 }
 351
 352 static void iblock_end_io_flush(struct bio *bio)
 353 {
 354         struct se_cmd *cmd = bio->bi_private;
 355
 356         if (bio->bi_error)
 357                 pr_err("IBLOCK: cache flush failed: %d\n", bio->bi_error);
 358
 359         if (cmd) {
 360                 if (bio->bi_error)
 361                         target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 362                 else
 363                         target_complete_cmd(cmd, SAM_STAT_GOOD);
 364         }
 365
 366         bio_put(bio);
 367 }
 368
 369 /*
 370  * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 371  * always flush the whole cache.
 372  */
 373 static sense_reason_t
 374 iblock_execute_sync_cache(struct se_cmd *cmd)
 375 {
 376         struct iblock_dev *ib_dev = IBLOCK_DEV(cmd->se_dev);
 377         int immed = (cmd->t_task_cdb[1] & 0x2);
 378         struct bio *bio;
 379
 380         /*
 381          * If the Immediate bit is set, queue up the GOOD response
 382          * for this SYNCHRONIZE_CACHE op.
 383          */
 384         if (immed)
 385                 target_complete_cmd(cmd, SAM_STAT_GOOD);
 386
 387         bio = bio_alloc(GFP_KERNEL, 0);
 388         bio->bi_end_io = iblock_end_io_flush;
 389         bio->bi_bdev = ib_dev->ibd_bd;
 390         if (!immed)
 391                 bio->bi_private = cmd;
 392         submit_bio(WRITE_FLUSH, bio);
 393         return 0;
 394 }
 395
 396 static sense_reason_t
 397 iblock_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
 398 {
 399         struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 400         struct se_device *dev = cmd->se_dev;
 401         int ret;
 402
 403         ret = blkdev_issue_discard(bdev,
 404                                    target_to_linux_sector(dev, lba),
 405                                    target_to_linux_sector(dev,  nolb),
 406                                    GFP_KERNEL, 0);
 407         if (ret < 0) {
 408                 pr_err("blkdev_issue_discard() failed: %d\n", ret);
 409                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 410         }
 411
 412         return 0;
 413 }
 414
 415 static sense_reason_t
 416 iblock_execute_write_same(struct se_cmd *cmd)
 417 {
 418         struct iblock_req *ibr;
 419         struct scatterlist *sg;
 420         struct bio *bio;
 421         struct bio_list list;
 422         struct se_device *dev = cmd->se_dev;
 423         sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
 424         sector_t sectors = target_to_linux_sector(dev,
 425                                         sbc_get_write_same_sectors(cmd));
 426
 427         if (cmd->prot_op) {
 428                 pr_err("WRITE_SAME: Protection information with IBLOCK"
 429                        " backends not supported\n");
 430                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 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 = kstrtoul(arg_p, 0, &tmp_readonly);
 540                         kfree(arg_p);
 541                         if (ret < 0) {
 542                                 pr_err("kstrtoul() 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 int
 590 iblock_alloc_bip(struct se_cmd *cmd, struct bio *bio)
 591 {
 592         struct se_device *dev = cmd->se_dev;
 593         struct blk_integrity *bi;
 594         struct bio_integrity_payload *bip;
 595         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 596         struct scatterlist *sg;
 597         int i, rc;
 598
 599         bi = bdev_get_integrity(ib_dev->ibd_bd);
 600         if (!bi) {
 601                 pr_err("Unable to locate bio_integrity\n");
 602                 return -ENODEV;
 603         }
 604
 605         bip = bio_integrity_alloc(bio, GFP_NOIO, cmd->t_prot_nents);
 606         if (!bip) {
 607                 pr_err("Unable to allocate bio_integrity_payload\n");
 608                 return -ENOMEM;
 609         }
 610
 611         bip->bip_iter.bi_size = (cmd->data_length / dev->dev_attrib.block_size) *
 612                          dev->prot_length;
 613         bip->bip_iter.bi_sector = bio->bi_iter.bi_sector;
 614
 615         pr_debug("IBLOCK BIP Size: %u Sector: %llu\n", bip->bip_iter.bi_size,
 616                  (unsigned long long)bip->bip_iter.bi_sector);
 617
 618         for_each_sg(cmd->t_prot_sg, sg, cmd->t_prot_nents, i) {
 619
 620                 rc = bio_integrity_add_page(bio, sg_page(sg), sg->length,
 621                                             sg->offset);
 622                 if (rc != sg->length) {
 623                         pr_err("bio_integrity_add_page() failed; %d\n", rc);
 624                         return -ENOMEM;
 625                 }
 626
 627                 pr_debug("Added bio integrity page: %p length: %d offset; %d\n",
 628                          sg_page(sg), sg->length, sg->offset);
 629         }
 630
 631         return 0;
 632 }
 633
 634 static sense_reason_t
 635 iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 636                   enum dma_data_direction data_direction)
 637 {
 638         struct se_device *dev = cmd->se_dev;
 639         sector_t block_lba = target_to_linux_sector(dev, cmd->t_task_lba);
 640         struct iblock_req *ibr;
 641         struct bio *bio, *bio_start;
 642         struct bio_list list;
 643         struct scatterlist *sg;
 644         u32 sg_num = sgl_nents;
 645         unsigned bio_cnt;
 646         int rw = 0;
 647         int i;
 648
 649         if (data_direction == DMA_TO_DEVICE) {
 650                 struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 651                 struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 652                 /*
 653                  * Force writethrough using WRITE_FUA if a volatile write cache
 654                  * is not enabled, or if initiator set the Force Unit Access bit.
 655                  */
 656                 if (q->flush_flags & REQ_FUA) {
 657                         if (cmd->se_cmd_flags & SCF_FUA)
 658                                 rw = WRITE_FUA;
 659                         else if (!(q->flush_flags & REQ_FLUSH))
 660                                 rw = WRITE_FUA;
 661                         else
 662                                 rw = WRITE;
 663                 } else {
 664                         rw = WRITE;
 665                 }
 666         } else {
 667                 rw = READ;
 668         }
 669
 670         ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 671         if (!ibr)
 672                 goto fail;
 673         cmd->priv = ibr;
 674
 675         if (!sgl_nents) {
 676                 atomic_set(&ibr->pending, 1);
 677                 iblock_complete_cmd(cmd);
 678                 return 0;
 679         }
 680
 681         bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 682         if (!bio)
 683                 goto fail_free_ibr;
 684
 685         bio_start = bio;
 686         bio_list_init(&list);
 687         bio_list_add(&list, bio);
 688
 689         atomic_set(&ibr->pending, 2);
 690         bio_cnt = 1;
 691
 692         for_each_sg(sgl, sg, sgl_nents, i) {
 693                 /*
 694                  * XXX: if the length the device accepts is shorter than the
 695                  *      length of the S/G list entry this will cause and
 696                  *      endless loop.  Better hope no driver uses huge pages.
 697                  */
 698                 while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 699                                 != sg->length) {
 700                         if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 701                                 iblock_submit_bios(&list, rw);
 702                                 bio_cnt = 0;
 703                         }
 704
 705                         bio = iblock_get_bio(cmd, block_lba, sg_num);
 706                         if (!bio)
 707                                 goto fail_put_bios;
 708
 709                         atomic_inc(&ibr->pending);
 710                         bio_list_add(&list, bio);
 711                         bio_cnt++;
 712                 }
 713
 714                 /* Always in 512 byte units for Linux/Block */
 715                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 716                 sg_num--;
 717         }
 718
 719         if (cmd->prot_type && dev->dev_attrib.pi_prot_type) {
 720                 int rc = iblock_alloc_bip(cmd, bio_start);
 721                 if (rc)
 722                         goto fail_put_bios;
 723         }
 724
 725         iblock_submit_bios(&list, rw);
 726         iblock_complete_cmd(cmd);
 727         return 0;
 728
 729 fail_put_bios:
 730         while ((bio = bio_list_pop(&list)))
 731                 bio_put(bio);
 732 fail_free_ibr:
 733         kfree(ibr);
 734 fail:
 735         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 736 }
 737
 738 static sector_t iblock_get_blocks(struct se_device *dev)
 739 {
 740         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 741         struct block_device *bd = ib_dev->ibd_bd;
 742         struct request_queue *q = bdev_get_queue(bd);
 743
 744         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 745 }
 746
 747 static sector_t iblock_get_alignment_offset_lbas(struct se_device *dev)
 748 {
 749         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 750         struct block_device *bd = ib_dev->ibd_bd;
 751         int ret;
 752
 753         ret = bdev_alignment_offset(bd);
 754         if (ret == -1)
 755                 return 0;
 756
 757         /* convert offset-bytes to offset-lbas */
 758         return ret / bdev_logical_block_size(bd);
 759 }
 760
 761 static unsigned int iblock_get_lbppbe(struct se_device *dev)
 762 {
 763         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 764         struct block_device *bd = ib_dev->ibd_bd;
 765         int logs_per_phys = bdev_physical_block_size(bd) / bdev_logical_block_size(bd);
 766
 767         return ilog2(logs_per_phys);
 768 }
 769
 770 static unsigned int iblock_get_io_min(struct se_device *dev)
 771 {
 772         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 773         struct block_device *bd = ib_dev->ibd_bd;
 774
 775         return bdev_io_min(bd);
 776 }
 777
 778 static unsigned int iblock_get_io_opt(struct se_device *dev)
 779 {
 780         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 781         struct block_device *bd = ib_dev->ibd_bd;
 782
 783         return bdev_io_opt(bd);
 784 }
 785
 786 static struct sbc_ops iblock_sbc_ops = {
 787         .execute_rw             = iblock_execute_rw,
 788         .execute_sync_cache     = iblock_execute_sync_cache,
 789         .execute_write_same     = iblock_execute_write_same,
 790         .execute_unmap          = iblock_execute_unmap,
 791 };
 792
 793 static sense_reason_t
 794 iblock_parse_cdb(struct se_cmd *cmd)
 795 {
 796         return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 797 }
 798
 799 static bool iblock_get_write_cache(struct se_device *dev)
 800 {
 801         struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 802         struct block_device *bd = ib_dev->ibd_bd;
 803         struct request_queue *q = bdev_get_queue(bd);
 804
 805         return q->flush_flags & REQ_FLUSH;
 806 }
 807
 808 static const struct target_backend_ops iblock_ops = {
 809         .name                   = "iblock",
 810         .inquiry_prod           = "IBLOCK",
 811         .inquiry_rev            = IBLOCK_VERSION,
 812         .owner                  = THIS_MODULE,
 813         .attach_hba             = iblock_attach_hba,
 814         .detach_hba             = iblock_detach_hba,
 815         .alloc_device           = iblock_alloc_device,
 816         .configure_device       = iblock_configure_device,
 817         .free_device            = iblock_free_device,
 818         .parse_cdb              = iblock_parse_cdb,
 819         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 820         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 821         .get_device_type        = sbc_get_device_type,
 822         .get_blocks             = iblock_get_blocks,
 823         .get_alignment_offset_lbas = iblock_get_alignment_offset_lbas,
 824         .get_lbppbe             = iblock_get_lbppbe,
 825         .get_io_min             = iblock_get_io_min,
 826         .get_io_opt             = iblock_get_io_opt,
 827         .get_write_cache        = iblock_get_write_cache,
 828         .tb_dev_attrib_attrs    = sbc_attrib_attrs,
 829 };
 830
 831 static int __init iblock_module_init(void)
 832 {
 833         return transport_backend_register(&iblock_ops);
 834 }
 835
 836 static void __exit iblock_module_exit(void)
 837 {
 838         target_backend_unregister(&iblock_ops);
 839 }
 840
 841 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 842 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 843 MODULE_LICENSE("GPL");
 844
 845 module_init(iblock_module_init);
 846 module_exit(iblock_module_exit);