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 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
   8 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   9 * Copyright (c) 2007-2010 Rising Tide Systems
  10 * Copyright (c) 2008-2010 Linux-iSCSI.org
  11 *
  12 * Nicholas A. Bellinger <nab@kernel.org>
  13 *
  14 * This program is free software; you can redistribute it and/or modify
  15 * it under the terms of the GNU General Public License as published by
  16 * the Free Software Foundation; either version 2 of the License, or
  17 * (at your option) any later version.
  18 *
  19 * This program is distributed in the hope that it will be useful,
  20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22 * GNU General Public License for more details.
  23 *
  24 * You should have received a copy of the GNU General Public License
  25 * along with this program; if not, write to the Free Software
  26 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27 *
  28 ******************************************************************************/
  29
  30#include <linux/string.h>
  31#include <linux/parser.h>
  32#include <linux/timer.h>
  33#include <linux/fs.h>
  34#include <linux/blkdev.h>
  35#include <linux/slab.h>
  36#include <linux/spinlock.h>
  37#include <linux/bio.h>
  38#include <linux/genhd.h>
  39#include <linux/file.h>
  40#include <linux/module.h>
  41#include <scsi/scsi.h>
  42#include <scsi/scsi_host.h>
  43#include <asm/unaligned.h>
  44
  45#include <target/target_core_base.h>
  46#include <target/target_core_backend.h>
  47
  48#include "target_core_iblock.h"
  49
  50#define IBLOCK_MAX_BIO_PER_TASK  32     /* max # of bios to submit at a time */
  51#define IBLOCK_BIO_POOL_SIZE    128
  52
  53static struct se_subsystem_api iblock_template;
  54
  55static void iblock_bio_done(struct bio *, int);
  56
  57/*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  58 *
  59 *
  60 */
  61static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  62{
  63        pr_debug("CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  64                " Generic Target Core Stack %s\n", hba->hba_id,
  65                IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  66        return 0;
  67}
  68
  69static void iblock_detach_hba(struct se_hba *hba)
  70{
  71}
  72
  73static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
  74{
  75        struct iblock_dev *ib_dev = NULL;
  76
  77        ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
  78        if (!ib_dev) {
  79                pr_err("Unable to allocate struct iblock_dev\n");
  80                return NULL;
  81        }
  82
  83        pr_debug( "IBLOCK: Allocated ib_dev for %s\n", name);
  84
  85        return ib_dev;
  86}
  87
  88static struct se_device *iblock_create_virtdevice(
  89        struct se_hba *hba,
  90        struct se_subsystem_dev *se_dev,
  91        void *p)
  92{
  93        struct iblock_dev *ib_dev = p;
  94        struct se_device *dev;
  95        struct se_dev_limits dev_limits;
  96        struct block_device *bd = NULL;
  97        struct request_queue *q;
  98        struct queue_limits *limits;
  99        u32 dev_flags = 0;
 100        fmode_t mode;
 101        int ret = -EINVAL;
 102
 103        if (!ib_dev) {
 104                pr_err("Unable to locate struct iblock_dev parameter\n");
 105                return ERR_PTR(ret);
 106        }
 107        memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 108
 109        ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
 110        if (!ib_dev->ibd_bio_set) {
 111                pr_err("IBLOCK: Unable to create bioset()\n");
 112                return ERR_PTR(-ENOMEM);
 113        }
 114        pr_debug("IBLOCK: Created bio_set()\n");
 115        /*
 116         * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 117         * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 118         */
 119        pr_debug( "IBLOCK: Claiming struct block_device: %s\n",
 120                        ib_dev->ibd_udev_path);
 121
 122        mode = FMODE_READ|FMODE_EXCL;
 123        if (!ib_dev->ibd_readonly)
 124                mode |= FMODE_WRITE;
 125
 126        bd = blkdev_get_by_path(ib_dev->ibd_udev_path, mode, ib_dev);
 127        if (IS_ERR(bd)) {
 128                ret = PTR_ERR(bd);
 129                goto failed;
 130        }
 131        /*
 132         * Setup the local scope queue_limits from struct request_queue->limits
 133         * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 134         */
 135        q = bdev_get_queue(bd);
 136        limits = &dev_limits.limits;
 137        limits->logical_block_size = bdev_logical_block_size(bd);
 138        limits->max_hw_sectors = UINT_MAX;
 139        limits->max_sectors = UINT_MAX;
 140        dev_limits.hw_queue_depth = q->nr_requests;
 141        dev_limits.queue_depth = q->nr_requests;
 142
 143        ib_dev->ibd_bd = bd;
 144
 145        dev = transport_add_device_to_core_hba(hba,
 146                        &iblock_template, se_dev, dev_flags, ib_dev,
 147                        &dev_limits, "IBLOCK", IBLOCK_VERSION);
 148        if (!dev)
 149                goto failed;
 150
 151        /*
 152         * Check if the underlying struct block_device request_queue supports
 153         * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 154         * in ATA and we need to set TPE=1
 155         */
 156        if (blk_queue_discard(q)) {
 157                dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 158                                q->limits.max_discard_sectors;
 159                /*
 160                 * Currently hardcoded to 1 in Linux/SCSI code..
 161                 */
 162                dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 163                dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 164                                q->limits.discard_granularity >> 9;
 165                dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 166                                q->limits.discard_alignment;
 167
 168                pr_debug("IBLOCK: BLOCK Discard support available,"
 169                                " disabled by default\n");
 170        }
 171
 172        if (blk_queue_nonrot(q))
 173                dev->se_sub_dev->se_dev_attrib.is_nonrot = 1;
 174
 175        return dev;
 176
 177failed:
 178        if (ib_dev->ibd_bio_set) {
 179                bioset_free(ib_dev->ibd_bio_set);
 180                ib_dev->ibd_bio_set = NULL;
 181        }
 182        ib_dev->ibd_bd = NULL;
 183        return ERR_PTR(ret);
 184}
 185
 186static void iblock_free_device(void *p)
 187{
 188        struct iblock_dev *ib_dev = p;
 189
 190        if (ib_dev->ibd_bd != NULL)
 191                blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 192        if (ib_dev->ibd_bio_set != NULL)
 193                bioset_free(ib_dev->ibd_bio_set);
 194        kfree(ib_dev);
 195}
 196
 197static unsigned long long iblock_emulate_read_cap_with_block_size(
 198        struct se_device *dev,
 199        struct block_device *bd,
 200        struct request_queue *q)
 201{
 202        unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 203                                        bdev_logical_block_size(bd)) - 1);
 204        u32 block_size = bdev_logical_block_size(bd);
 205
 206        if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 207                return blocks_long;
 208
 209        switch (block_size) {
 210        case 4096:
 211                switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 212                case 2048:
 213                        blocks_long <<= 1;
 214                        break;
 215                case 1024:
 216                        blocks_long <<= 2;
 217                        break;
 218                case 512:
 219                        blocks_long <<= 3;
 220                default:
 221                        break;
 222                }
 223                break;
 224        case 2048:
 225                switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 226                case 4096:
 227                        blocks_long >>= 1;
 228                        break;
 229                case 1024:
 230                        blocks_long <<= 1;
 231                        break;
 232                case 512:
 233                        blocks_long <<= 2;
 234                        break;
 235                default:
 236                        break;
 237                }
 238                break;
 239        case 1024:
 240                switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 241                case 4096:
 242                        blocks_long >>= 2;
 243                        break;
 244                case 2048:
 245                        blocks_long >>= 1;
 246                        break;
 247                case 512:
 248                        blocks_long <<= 1;
 249                        break;
 250                default:
 251                        break;
 252                }
 253                break;
 254        case 512:
 255                switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 256                case 4096:
 257                        blocks_long >>= 3;
 258                        break;
 259                case 2048:
 260                        blocks_long >>= 2;
 261                        break;
 262                case 1024:
 263                        blocks_long >>= 1;
 264                        break;
 265                default:
 266                        break;
 267                }
 268                break;
 269        default:
 270                break;
 271        }
 272
 273        return blocks_long;
 274}
 275
 276static void iblock_end_io_flush(struct bio *bio, int err)
 277{
 278        struct se_cmd *cmd = bio->bi_private;
 279
 280        if (err)
 281                pr_err("IBLOCK: cache flush failed: %d\n", err);
 282
 283        if (cmd) {
 284                if (err) {
 285                        cmd->scsi_sense_reason =
 286                                TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 287                        target_complete_cmd(cmd, SAM_STAT_CHECK_CONDITION);
 288                } else {
 289                        target_complete_cmd(cmd, SAM_STAT_GOOD);
 290                }
 291        }
 292
 293        bio_put(bio);
 294}
 295
 296/*
 297 * Implement SYCHRONIZE CACHE.  Note that we can't handle lba ranges and must
 298 * always flush the whole cache.
 299 */
 300static int iblock_execute_sync_cache(struct se_cmd *cmd)
 301{
 302        struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 303        int immed = (cmd->t_task_cdb[1] & 0x2);
 304        struct bio *bio;
 305
 306        /*
 307         * If the Immediate bit is set, queue up the GOOD response
 308         * for this SYNCHRONIZE_CACHE op.
 309         */
 310        if (immed)
 311                target_complete_cmd(cmd, SAM_STAT_GOOD);
 312
 313        bio = bio_alloc(GFP_KERNEL, 0);
 314        bio->bi_end_io = iblock_end_io_flush;
 315        bio->bi_bdev = ib_dev->ibd_bd;
 316        if (!immed)
 317                bio->bi_private = cmd;
 318        submit_bio(WRITE_FLUSH, bio);
 319        return 0;
 320}
 321
 322static int iblock_execute_unmap(struct se_cmd *cmd)
 323{
 324        struct se_device *dev = cmd->se_dev;
 325        struct iblock_dev *ibd = dev->dev_ptr;
 326        unsigned char *buf, *ptr = NULL;
 327        sector_t lba;
 328        int size;
 329        u32 range;
 330        int ret = 0;
 331        int dl, bd_dl;
 332
 333        if (cmd->data_length < 8) {
 334                pr_warn("UNMAP parameter list length %u too small\n",
 335                        cmd->data_length);
 336                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 337                return -EINVAL;
 338        }
 339
 340        buf = transport_kmap_data_sg(cmd);
 341
 342        dl = get_unaligned_be16(&buf[0]);
 343        bd_dl = get_unaligned_be16(&buf[2]);
 344
 345        size = cmd->data_length - 8;
 346        if (bd_dl > size)
 347                pr_warn("UNMAP parameter list length %u too small, ignoring bd_dl %u\n",
 348                        cmd->data_length, bd_dl);
 349        else
 350                size = bd_dl;
 351
 352        if (size / 16 > dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count) {
 353                cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 354                ret = -EINVAL;
 355                goto err;
 356        }
 357
 358        /* First UNMAP block descriptor starts at 8 byte offset */
 359        ptr = &buf[8];
 360        pr_debug("UNMAP: Sub: %s Using dl: %u bd_dl: %u size: %u"
 361                " ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
 362
 363        while (size >= 16) {
 364                lba = get_unaligned_be64(&ptr[0]);
 365                range = get_unaligned_be32(&ptr[8]);
 366                pr_debug("UNMAP: Using lba: %llu and range: %u\n",
 367                                 (unsigned long long)lba, range);
 368
 369                if (range > dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count) {
 370                        cmd->scsi_sense_reason = TCM_INVALID_PARAMETER_LIST;
 371                        ret = -EINVAL;
 372                        goto err;
 373                }
 374
 375                if (lba + range > dev->transport->get_blocks(dev) + 1) {
 376                        cmd->scsi_sense_reason = TCM_ADDRESS_OUT_OF_RANGE;
 377                        ret = -EINVAL;
 378                        goto err;
 379                }
 380
 381                ret = blkdev_issue_discard(ibd->ibd_bd, lba, range,
 382                                           GFP_KERNEL, 0);
 383                if (ret < 0) {
 384                        pr_err("blkdev_issue_discard() failed: %d\n",
 385                                        ret);
 386                        goto err;
 387                }
 388
 389                ptr += 16;
 390                size -= 16;
 391        }
 392
 393err:
 394        transport_kunmap_data_sg(cmd);
 395        if (!ret)
 396                target_complete_cmd(cmd, GOOD);
 397        return ret;
 398}
 399
 400static int iblock_execute_write_same(struct se_cmd *cmd)
 401{
 402        struct iblock_dev *ibd = cmd->se_dev->dev_ptr;
 403        int ret;
 404
 405        ret = blkdev_issue_discard(ibd->ibd_bd, cmd->t_task_lba,
 406                                   spc_get_write_same_sectors(cmd), GFP_KERNEL,
 407                                   0);
 408        if (ret < 0) {
 409                pr_debug("blkdev_issue_discard() failed for WRITE_SAME\n");
 410                return ret;
 411        }
 412
 413        target_complete_cmd(cmd, GOOD);
 414        return 0;
 415}
 416
 417enum {
 418        Opt_udev_path, Opt_readonly, Opt_force, Opt_err
 419};
 420
 421static match_table_t tokens = {
 422        {Opt_udev_path, "udev_path=%s"},
 423        {Opt_readonly, "readonly=%d"},
 424        {Opt_force, "force=%d"},
 425        {Opt_err, NULL}
 426};
 427
 428static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 429                                               struct se_subsystem_dev *se_dev,
 430                                               const char *page, ssize_t count)
 431{
 432        struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 433        char *orig, *ptr, *arg_p, *opts;
 434        substring_t args[MAX_OPT_ARGS];
 435        int ret = 0, token;
 436        unsigned long tmp_readonly;
 437
 438        opts = kstrdup(page, GFP_KERNEL);
 439        if (!opts)
 440                return -ENOMEM;
 441
 442        orig = opts;
 443
 444        while ((ptr = strsep(&opts, ",\n")) != NULL) {
 445                if (!*ptr)
 446                        continue;
 447
 448                token = match_token(ptr, tokens, args);
 449                switch (token) {
 450                case Opt_udev_path:
 451                        if (ib_dev->ibd_bd) {
 452                                pr_err("Unable to set udev_path= while"
 453                                        " ib_dev->ibd_bd exists\n");
 454                                ret = -EEXIST;
 455                                goto out;
 456                        }
 457                        if (match_strlcpy(ib_dev->ibd_udev_path, &args[0],
 458                                SE_UDEV_PATH_LEN) == 0) {
 459                                ret = -EINVAL;
 460                                break;
 461                        }
 462                        pr_debug("IBLOCK: Referencing UDEV path: %s\n",
 463                                        ib_dev->ibd_udev_path);
 464                        ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 465                        break;
 466                case Opt_readonly:
 467                        arg_p = match_strdup(&args[0]);
 468                        if (!arg_p) {
 469                                ret = -ENOMEM;
 470                                break;
 471                        }
 472                        ret = strict_strtoul(arg_p, 0, &tmp_readonly);
 473                        kfree(arg_p);
 474                        if (ret < 0) {
 475                                pr_err("strict_strtoul() failed for"
 476                                                " readonly=\n");
 477                                goto out;
 478                        }
 479                        ib_dev->ibd_readonly = tmp_readonly;
 480                        pr_debug("IBLOCK: readonly: %d\n", ib_dev->ibd_readonly);
 481                        break;
 482                case Opt_force:
 483                        break;
 484                default:
 485                        break;
 486                }
 487        }
 488
 489out:
 490        kfree(orig);
 491        return (!ret) ? count : ret;
 492}
 493
 494static ssize_t iblock_check_configfs_dev_params(
 495        struct se_hba *hba,
 496        struct se_subsystem_dev *se_dev)
 497{
 498        struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 499
 500        if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 501                pr_err("Missing udev_path= parameters for IBLOCK\n");
 502                return -EINVAL;
 503        }
 504
 505        return 0;
 506}
 507
 508static ssize_t iblock_show_configfs_dev_params(
 509        struct se_hba *hba,
 510        struct se_subsystem_dev *se_dev,
 511        char *b)
 512{
 513        struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 514        struct block_device *bd = ibd->ibd_bd;
 515        char buf[BDEVNAME_SIZE];
 516        ssize_t bl = 0;
 517
 518        if (bd)
 519                bl += sprintf(b + bl, "iBlock device: %s",
 520                                bdevname(bd, buf));
 521        if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH)
 522                bl += sprintf(b + bl, "  UDEV PATH: %s",
 523                                ibd->ibd_udev_path);
 524        bl += sprintf(b + bl, "  readonly: %d\n", ibd->ibd_readonly);
 525
 526        bl += sprintf(b + bl, "        ");
 527        if (bd) {
 528                bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 529                        MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 530                        "" : (bd->bd_holder == ibd) ?
 531                        "CLAIMED: IBLOCK" : "CLAIMED: OS");
 532        } else {
 533                bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 534        }
 535
 536        return bl;
 537}
 538
 539static void iblock_complete_cmd(struct se_cmd *cmd)
 540{
 541        struct iblock_req *ibr = cmd->priv;
 542        u8 status;
 543
 544        if (!atomic_dec_and_test(&ibr->pending))
 545                return;
 546
 547        if (atomic_read(&ibr->ib_bio_err_cnt))
 548                status = SAM_STAT_CHECK_CONDITION;
 549        else
 550                status = SAM_STAT_GOOD;
 551
 552        target_complete_cmd(cmd, status);
 553        kfree(ibr);
 554}
 555
 556static struct bio *
 557iblock_get_bio(struct se_cmd *cmd, sector_t lba, u32 sg_num)
 558{
 559        struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 560        struct bio *bio;
 561
 562        /*
 563         * Only allocate as many vector entries as the bio code allows us to,
 564         * we'll loop later on until we have handled the whole request.
 565         */
 566        if (sg_num > BIO_MAX_PAGES)
 567                sg_num = BIO_MAX_PAGES;
 568
 569        bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 570        if (!bio) {
 571                pr_err("Unable to allocate memory for bio\n");
 572                return NULL;
 573        }
 574
 575        bio->bi_bdev = ib_dev->ibd_bd;
 576        bio->bi_private = cmd;
 577        bio->bi_end_io = &iblock_bio_done;
 578        bio->bi_sector = lba;
 579        return bio;
 580}
 581
 582static void iblock_submit_bios(struct bio_list *list, int rw)
 583{
 584        struct blk_plug plug;
 585        struct bio *bio;
 586
 587        blk_start_plug(&plug);
 588        while ((bio = bio_list_pop(list)))
 589                submit_bio(rw, bio);
 590        blk_finish_plug(&plug);
 591}
 592
 593static int iblock_execute_rw(struct se_cmd *cmd)
 594{
 595        struct scatterlist *sgl = cmd->t_data_sg;
 596        u32 sgl_nents = cmd->t_data_nents;
 597        enum dma_data_direction data_direction = cmd->data_direction;
 598        struct se_device *dev = cmd->se_dev;
 599        struct iblock_req *ibr;
 600        struct bio *bio;
 601        struct bio_list list;
 602        struct scatterlist *sg;
 603        u32 sg_num = sgl_nents;
 604        sector_t block_lba;
 605        unsigned bio_cnt;
 606        int rw;
 607        int i;
 608
 609        if (data_direction == DMA_TO_DEVICE) {
 610                /*
 611                 * Force data to disk if we pretend to not have a volatile
 612                 * write cache, or the initiator set the Force Unit Access bit.
 613                 */
 614                if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 615                    (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 616                     (cmd->se_cmd_flags & SCF_FUA)))
 617                        rw = WRITE_FUA;
 618                else
 619                        rw = WRITE;
 620        } else {
 621                rw = READ;
 622        }
 623
 624        /*
 625         * Convert the blocksize advertised to the initiator to the 512 byte
 626         * units unconditionally used by the Linux block layer.
 627         */
 628        if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 629                block_lba = (cmd->t_task_lba << 3);
 630        else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 631                block_lba = (cmd->t_task_lba << 2);
 632        else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 633                block_lba = (cmd->t_task_lba << 1);
 634        else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 635                block_lba = cmd->t_task_lba;
 636        else {
 637                pr_err("Unsupported SCSI -> BLOCK LBA conversion:"
 638                                " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 639                cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 640                return -ENOSYS;
 641        }
 642
 643        ibr = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 644        if (!ibr)
 645                goto fail;
 646        cmd->priv = ibr;
 647
 648        if (!sgl_nents) {
 649                atomic_set(&ibr->pending, 1);
 650                iblock_complete_cmd(cmd);
 651                return 0;
 652        }
 653
 654        bio = iblock_get_bio(cmd, block_lba, sgl_nents);
 655        if (!bio)
 656                goto fail_free_ibr;
 657
 658        bio_list_init(&list);
 659        bio_list_add(&list, bio);
 660
 661        atomic_set(&ibr->pending, 2);
 662        bio_cnt = 1;
 663
 664        for_each_sg(sgl, sg, sgl_nents, i) {
 665                /*
 666                 * XXX: if the length the device accepts is shorter than the
 667                 *      length of the S/G list entry this will cause and
 668                 *      endless loop.  Better hope no driver uses huge pages.
 669                 */
 670                while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 671                                != sg->length) {
 672                        if (bio_cnt >= IBLOCK_MAX_BIO_PER_TASK) {
 673                                iblock_submit_bios(&list, rw);
 674                                bio_cnt = 0;
 675                        }
 676
 677                        bio = iblock_get_bio(cmd, block_lba, sg_num);
 678                        if (!bio)
 679                                goto fail_put_bios;
 680
 681                        atomic_inc(&ibr->pending);
 682                        bio_list_add(&list, bio);
 683                        bio_cnt++;
 684                }
 685
 686                /* Always in 512 byte units for Linux/Block */
 687                block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 688                sg_num--;
 689        }
 690
 691        iblock_submit_bios(&list, rw);
 692        iblock_complete_cmd(cmd);
 693        return 0;
 694
 695fail_put_bios:
 696        while ((bio = bio_list_pop(&list)))
 697                bio_put(bio);
 698fail_free_ibr:
 699        kfree(ibr);
 700        cmd->scsi_sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 701fail:
 702        return -ENOMEM;
 703}
 704
 705static u32 iblock_get_device_rev(struct se_device *dev)
 706{
 707        return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 708}
 709
 710static u32 iblock_get_device_type(struct se_device *dev)
 711{
 712        return TYPE_DISK;
 713}
 714
 715static sector_t iblock_get_blocks(struct se_device *dev)
 716{
 717        struct iblock_dev *ibd = dev->dev_ptr;
 718        struct block_device *bd = ibd->ibd_bd;
 719        struct request_queue *q = bdev_get_queue(bd);
 720
 721        return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 722}
 723
 724static void iblock_bio_done(struct bio *bio, int err)
 725{
 726        struct se_cmd *cmd = bio->bi_private;
 727        struct iblock_req *ibr = cmd->priv;
 728
 729        /*
 730         * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 731         */
 732        if (!test_bit(BIO_UPTODATE, &bio->bi_flags) && !err)
 733                err = -EIO;
 734
 735        if (err != 0) {
 736                pr_err("test_bit(BIO_UPTODATE) failed for bio: %p,"
 737                        " err: %d\n", bio, err);
 738                /*
 739                 * Bump the ib_bio_err_cnt and release bio.
 740                 */
 741                atomic_inc(&ibr->ib_bio_err_cnt);
 742                smp_mb__after_atomic_inc();
 743        }
 744
 745        bio_put(bio);
 746
 747        iblock_complete_cmd(cmd);
 748}
 749
 750static struct spc_ops iblock_spc_ops = {
 751        .execute_rw             = iblock_execute_rw,
 752        .execute_sync_cache     = iblock_execute_sync_cache,
 753        .execute_write_same     = iblock_execute_write_same,
 754        .execute_unmap          = iblock_execute_unmap,
 755};
 756
 757static int iblock_parse_cdb(struct se_cmd *cmd)
 758{
 759        return sbc_parse_cdb(cmd, &iblock_spc_ops);
 760}
 761
 762static struct se_subsystem_api iblock_template = {
 763        .name                   = "iblock",
 764        .owner                  = THIS_MODULE,
 765        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 766        .attach_hba             = iblock_attach_hba,
 767        .detach_hba             = iblock_detach_hba,
 768        .allocate_virtdevice    = iblock_allocate_virtdevice,
 769        .create_virtdevice      = iblock_create_virtdevice,
 770        .free_device            = iblock_free_device,
 771        .parse_cdb              = iblock_parse_cdb,
 772        .check_configfs_dev_params = iblock_check_configfs_dev_params,
 773        .set_configfs_dev_params = iblock_set_configfs_dev_params,
 774        .show_configfs_dev_params = iblock_show_configfs_dev_params,
 775        .get_device_rev         = iblock_get_device_rev,
 776        .get_device_type        = iblock_get_device_type,
 777        .get_blocks             = iblock_get_blocks,
 778};
 779
 780static int __init iblock_module_init(void)
 781{
 782        return transport_subsystem_register(&iblock_template);
 783}
 784
 785static void iblock_module_exit(void)
 786{
 787        transport_subsystem_release(&iblock_template);
 788}
 789
 790MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 791MODULE_AUTHOR("nab@Linux-iSCSI.org");
 792MODULE_LICENSE("GPL");
 793
 794module_init(iblock_module_init);
 795module_exit(iblock_module_exit);
 796
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