linux/drivers/target/target_core_iblock.c
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   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
  50static inline struct iblock_dev *IBLOCK_DEV(struct se_device *dev)
  51{
  52        return container_of(dev, struct iblock_dev, dev);
  53}
  54
  55
  56static struct se_subsystem_api iblock_template;
  57
  58/*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  59 *
  60 *
  61 */
  62static 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
  70static void iblock_detach_hba(struct se_hba *hba)
  71{
  72}
  73
  74static 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
  89static 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
 160out_free_bioset:
 161        bioset_free(ib_dev->ibd_bio_set);
 162        ib_dev->ibd_bio_set = NULL;
 163out:
 164        return ret;
 165}
 166
 167static 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
 178static 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
 257static 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
 274static 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
 300static struct bio *
 301iblock_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
 327static 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
 338static 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 */
 359static sense_reason_t
 360iblock_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
 382static sense_reason_t
 383iblock_do_unmap(struct se_cmd *cmd, void *priv,
 384                sector_t lba, sector_t nolb)
 385{
 386        struct block_device *bdev = priv;
 387        int ret;
 388
 389        ret = blkdev_issue_discard(bdev, lba, nolb, GFP_KERNEL, 0);
 390        if (ret < 0) {
 391                pr_err("blkdev_issue_discard() failed: %d\n", ret);
 392                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 393        }
 394
 395        return 0;
 396}
 397
 398static sense_reason_t
 399iblock_execute_unmap(struct se_cmd *cmd)
 400{
 401        struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 402
 403        return sbc_execute_unmap(cmd, iblock_do_unmap, bdev);
 404}
 405
 406static sense_reason_t
 407iblock_execute_write_same_unmap(struct se_cmd *cmd)
 408{
 409        struct block_device *bdev = IBLOCK_DEV(cmd->se_dev)->ibd_bd;
 410        sector_t lba = cmd->t_task_lba;
 411        sector_t nolb = sbc_get_write_same_sectors(cmd);
 412        int ret;
 413
 414        ret = iblock_do_unmap(cmd, bdev, lba, nolb);
 415        if (ret)
 416                return ret;
 417
 418        target_complete_cmd(cmd, GOOD);
 419        return 0;
 420}
 421
 422static sense_reason_t
 423iblock_execute_write_same(struct se_cmd *cmd)
 424{
 425        struct iblock_req *ibr;
 426        struct scatterlist *sg;
 427        struct bio *bio;
 428        struct bio_list list;
 429        sector_t block_lba = cmd->t_task_lba;
 430        sector_t sectors = sbc_get_write_same_sectors(cmd);
 431
 432        sg = &cmd->t_data_sg[0];
 433
 434        if (cmd->t_data_nents > 1 ||
 435            sg->length != cmd->se_dev->dev_attrib.block_size) {
 436                pr_err("WRITE_SAME: Illegal SGL t_data_nents: %u length: %u"
 437                        " block_size: %u\n", cmd->t_data_nents, sg->length,
 438                        cmd->se_dev->dev_attrib.block_size);
 439                return TCM_INVALID_CDB_FIELD;
 440        }
 441
 442        ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 443        if (!ibr)
 444                goto fail;
 445        cmd->priv = ibr;
 446
 447        bio = iblock_get_bio(cmd, block_lba, 1);
 448        if (!bio)
 449                goto fail_free_ibr;
 450
 451        bio_list_init(&list);
 452        bio_list_add(&list, bio);
 453
 454        atomic_set(&ibr->pending, 1);
 455
 456        while (sectors) {
 457                while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 458                                != sg->length) {
 459
 460                        bio = iblock_get_bio(cmd, block_lba, 1);
 461                        if (!bio)
 462                                goto fail_put_bios;
 463
 464                        atomic_inc(&ibr->pending);
 465                        bio_list_add(&list, bio);
 466                }
 467
 468                /* Always in 512 byte units for Linux/Block */
 469                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 470                sectors -= 1;
 471        }
 472
 473        iblock_submit_bios(&list, WRITE);
 474        return 0;
 475
 476fail_put_bios:
 477        while ((bio = bio_list_pop(&list)))
 478                bio_put(bio);
 479fail_free_ibr:
 480        kfree(ibr);
 481fail:
 482        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 483}
 484
 485enum {
 486        Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 487};
 488
 489static 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
 496static ssize_t iblock_set_configfs_dev_params(struct se_device *dev,
 497                const char *page, ssize_t count)
 498{
 499        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 500        char *orig, *ptr, *arg_p, *opts;
 501        substring_t args[MAX_OPT_ARGS];
 502        int ret = 0, token;
 503        unsigned long tmp_readonly;
 504
 505        opts = kstrdup(page, GFP_KERNEL);
 506        if (!opts)
 507                return -ENOMEM;
 508
 509        orig = opts;
 510
 511        while ((ptr = strsep(&opts, ",\n")) != NULL) {
 512                if (!*ptr)
 513                        continue;
 514
 515                token = match_token(ptr, tokens, args);
 516                switch (token) {
 517                case Opt_udev_path:
 518                        if (ib_dev->ibd_bd) {
 519                                pr_err("Unable to set udev_path= while"
 520                                        " ib_dev->ibd_bd exists\n");
 521                                ret = -EEXIST;
 522                                goto out;
 523                        }
 524                        if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 525                                SE_UDEV_PATH_LEN) == 0) {
 526                                ret = -EINVAL;
 527                                break;
 528                        }
 529                        pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 530                                        ib_dev->ibd_udev_path);
 531                        ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 532                        break;
 533                case Opt_readonly:
 534                        arg_p = match_strdup(&args[0]);
 535                        if (!arg_p) {
 536                                ret = -ENOMEM;
 537                                break;
 538                        }
 539                        ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 540                        kfree(arg_p);
 541                        if (ret < 0) {
 542                                pr_err("strict_strtoul() failed for"
 543                                                " readonly=\n");
 544                                goto out;
 545                        }
 546                        ib_dev->ibd_readonly = tmp_readonly;
 547                        pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 548                        break;
 549                case Opt_force:
 550                        break;
 551                default:
 552                        break;
 553                }
 554        }
 555
 556out:
 557        kfree(orig);
 558        return (!ret) ? count : ret;
 559}
 560
 561static 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
 589static sense_reason_t
 590iblock_execute_rw(struct se_cmd *cmd)
 591{
 592        struct scatterlist *sgl = cmd->t_data_sg;
 593        u32 sgl_nents = cmd->t_data_nents;
 594        enum dma_data_direction data_direction = cmd->data_direction;
 595        struct se_device *dev = cmd->se_dev;
 596        struct iblock_req *ibr;
 597        struct bio *bio;
 598        struct bio_list list;
 599        struct scatterlist *sg;
 600        u32 sg_num = sgl_nents;
 601        sector_t block_lba;
 602        unsigned bio_cnt;
 603        int rw = 0;
 604        int i;
 605
 606        if (data_direction == DMA_TO_DEVICE) {
 607                struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 608                struct request_queue *q = bdev_get_queue(ib_dev->ibd_bd);
 609                /*
 610                 * Force writethrough using WRITE_FUA if a volatile write cache
 611                 * is not enabled, or if initiator set the Force Unit Access bit.
 612                 */
 613                if (q->flush_flags & REQ_FUA) {
 614                        if (cmd->se_cmd_flags & SCF_FUA)
 615                                rw = WRITE_FUA;
 616                        else if (!(q->flush_flags & REQ_FLUSH))
 617                                rw = WRITE_FUA;
 618                        else
 619                                rw = WRITE;
 620                } else {
 621                        rw = WRITE;
 622                }
 623        } else {
 624                rw = READ;
 625        }
 626
 627        /*
 628         * Convert the blocksize advertised to the initiator to the 512 byte
 629         * units unconditionally used by the Linux block layer.
 630         */
 631        if (dev->dev_attrib.block_size == 4096)
 632                block_lba = (cmd->t_task_lba << 3);
 633        else if (dev->dev_attrib.block_size == 2048)
 634                block_lba = (cmd->t_task_lba << 2);
 635        else if (dev->dev_attrib.block_size == 1024)
 636                block_lba = (cmd->t_task_lba << 1);
 637        else if (dev->dev_attrib.block_size == 512)
 638                block_lba = cmd->t_task_lba;
 639        else {
 640                pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 641                                " %u\n", dev->dev_attrib.block_size);
 642                return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 643        }
 644
 645        ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 646        if (!ibr)
 647                goto fail;
 648        cmd->priv = ibr;
 649
 650        if (!sgl_nents) {
 651                atomic_set(&ibr->pending, 1);
 652                iblock_complete_cmd(cmd);
 653                return 0;
 654        }
 655
 656        bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 657        if (!bio)
 658                goto fail_free_ibr;
 659
 660        bio_list_init(&list);
 661        bio_list_add(&list, bio);
 662
 663        atomic_set(&ibr->pending, 2);
 664        bio_cnt = 1;
 665
 666        for_each_sg(sgl, sg, sgl_nents, i) {
 667                /*
 668                 * XXX: if the length the device accepts is shorter than the
 669                 *      length of the S/G list entry this will cause and
 670                 *      endless loop.  Better hope no driver uses huge pages.
 671                 */
 672                while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 673                                != sg->length) {
 674                        if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 675                                iblock_submit_bios(&list, rw);
 676                                bio_cnt = 0;
 677                        }
 678
 679                        bio = iblock_get_bio(cmd, block_lba, sg_num);
 680                        if (!bio)
 681                                goto fail_put_bios;
 682
 683                        atomic_inc(&ibr->pending);
 684                        bio_list_add(&list, bio);
 685                        bio_cnt++;
 686                }
 687
 688                /* Always in 512 byte units for Linux/Block */
 689                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 690                sg_num--;
 691        }
 692
 693        iblock_submit_bios(&list, rw);
 694        iblock_complete_cmd(cmd);
 695        return 0;
 696
 697fail_put_bios:
 698        while ((bio = bio_list_pop(&list)))
 699                bio_put(bio);
 700fail_free_ibr:
 701        kfree(ibr);
 702fail:
 703        return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 704}
 705
 706static sector_t iblock_get_blocks(struct se_device *dev)
 707{
 708        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 709        struct block_device *bd = ib_dev->ibd_bd;
 710        struct request_queue *q = bdev_get_queue(bd);
 711
 712        return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 713}
 714
 715static struct sbc_ops iblock_sbc_ops = {
 716        .execute_rw             = iblock_execute_rw,
 717        .execute_sync_cache     = iblock_execute_sync_cache,
 718        .execute_write_same     = iblock_execute_write_same,
 719        .execute_write_same_unmap = iblock_execute_write_same_unmap,
 720        .execute_unmap          = iblock_execute_unmap,
 721};
 722
 723static sense_reason_t
 724iblock_parse_cdb(struct se_cmd *cmd)
 725{
 726        return sbc_parse_cdb(cmd, &iblock_sbc_ops);
 727}
 728
 729bool iblock_get_write_cache(struct se_device *dev)
 730{
 731        struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 732        struct block_device *bd = ib_dev->ibd_bd;
 733        struct request_queue *q = bdev_get_queue(bd);
 734
 735        return q->flush_flags & REQ_FLUSH;
 736}
 737
 738static struct se_subsystem_api iblock_template = {
 739        .name                   = "iblock",
 740        .inquiry_prod           = "IBLOCK",
 741        .inquiry_rev            = IBLOCK_VERSION,
 742        .owner                  = THIS_MODULE,
 743        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 744        .attach_hba             = iblock_attach_hba,
 745        .detach_hba             = iblock_detach_hba,
 746        .alloc_device           = iblock_alloc_device,
 747        .configure_device       = iblock_configure_device,
 748        .free_device            = iblock_free_device,
 749        .parse_cdb              = iblock_parse_cdb,
 750        .set_configfs_dev_params = iblock_set_configfs_dev_params,
 751        .show_configfs_dev_params = iblock_show_configfs_dev_params,
 752        .get_device_type        = sbc_get_device_type,
 753        .get_blocks             = iblock_get_blocks,
 754        .get_write_cache        = iblock_get_write_cache,
 755};
 756
 757static int __init iblock_module_init(void)
 758{
 759        return transport_subsystem_register(&iblock_template);
 760}
 761
 762static void __exit iblock_module_exit(void)
 763{
 764        transport_subsystem_release(&iblock_template);
 765}
 766
 767MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 768MODULE_AUTHOR("nab@Linux-iSCSI.org");
 769MODULE_LICENSE("GPL");
 770
 771module_init(iblock_module_init);
 772module_exit(iblock_module_exit);
 773
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