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  * 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/version.h>
  31 #include <linux/string.h>
  32 #include <linux/parser.h>
  33 #include <linux/timer.h>
  34 #include <linux/fs.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/slab.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/bio.h>
  39 #include <linux/genhd.h>
  40 #include <linux/file.h>
  41 #include <scsi/scsi.h>
  42 #include <scsi/scsi_host.h>
  43
  44 #include <target/target_core_base.h>
  45 #include <target/target_core_device.h>
  46 #include <target/target_core_transport.h>
  47
  48 #include "target_core_iblock.h"
  49
  50 #if 0
  51 #define DEBUG_IBLOCK(x...) printk(x)
  52 #else
  53 #define DEBUG_IBLOCK(x...)
  54 #endif
  55
  56 static struct se_subsystem_api iblock_template;
  57
  58 static void iblock_bio_done(struct bio *, int);
  59
  60 /*      iblock_attach_hba(): (Part of se_subsystem_api_t template)
  61  *
  62  *
  63  */
  64 static int iblock_attach_hba(struct se_hba *hba, u32 host_id)
  65 {
  66         struct iblock_hba *ib_host;
  67
  68         ib_host = kzalloc(sizeof(struct iblock_hba), GFP_KERNEL);
  69         if (!(ib_host)) {
  70                 printk(KERN_ERR "Unable to allocate memory for"
  71                                 " struct iblock_hba\n");
  72                 return -ENOMEM;
  73         }
  74
  75         ib_host->iblock_host_id = host_id;
  76
  77         hba->hba_ptr = ib_host;
  78
  79         printk(KERN_INFO "CORE_HBA[%d] - TCM iBlock HBA Driver %s on"
  80                 " Generic Target Core Stack %s\n", hba->hba_id,
  81                 IBLOCK_VERSION, TARGET_CORE_MOD_VERSION);
  82
  83         printk(KERN_INFO "CORE_HBA[%d] - Attached iBlock HBA: %u to Generic\n",
  84                 hba->hba_id, ib_host->iblock_host_id);
  85
  86         return 0;
  87 }
  88
  89 static void iblock_detach_hba(struct se_hba *hba)
  90 {
  91         struct iblock_hba *ib_host = hba->hba_ptr;
  92
  93         printk(KERN_INFO "CORE_HBA[%d] - Detached iBlock HBA: %u from Generic"
  94                 " Target Core\n", hba->hba_id, ib_host->iblock_host_id);
  95
  96         kfree(ib_host);
  97         hba->hba_ptr = NULL;
  98 }
  99
 100 static void *iblock_allocate_virtdevice(struct se_hba *hba, const char *name)
 101 {
 102         struct iblock_dev *ib_dev = NULL;
 103         struct iblock_hba *ib_host = hba->hba_ptr;
 104
 105         ib_dev = kzalloc(sizeof(struct iblock_dev), GFP_KERNEL);
 106         if (!(ib_dev)) {
 107                 printk(KERN_ERR "Unable to allocate struct iblock_dev\n");
 108                 return NULL;
 109         }
 110         ib_dev->ibd_host = ib_host;
 111
 112         printk(KERN_INFO  "IBLOCK: Allocated ib_dev for %s\n", name);
 113
 114         return ib_dev;
 115 }
 116
 117 static struct se_device *iblock_create_virtdevice(
 118         struct se_hba *hba,
 119         struct se_subsystem_dev *se_dev,
 120         void *p)
 121 {
 122         struct iblock_dev *ib_dev = p;
 123         struct se_device *dev;
 124         struct se_dev_limits dev_limits;
 125         struct block_device *bd = NULL;
 126         struct request_queue *q;
 127         struct queue_limits *limits;
 128         u32 dev_flags = 0;
 129         int ret = -EINVAL;
 130
 131         if (!(ib_dev)) {
 132                 printk(KERN_ERR "Unable to locate struct iblock_dev parameter\n");
 133                 return ERR_PTR(ret);
 134         }
 135         memset(&dev_limits, 0, sizeof(struct se_dev_limits));
 136         /*
 137          * These settings need to be made tunable..
 138          */
 139         ib_dev->ibd_bio_set = bioset_create(32, 64);
 140         if (!(ib_dev->ibd_bio_set)) {
 141                 printk(KERN_ERR "IBLOCK: Unable to create bioset()\n");
 142                 return ERR_PTR(-ENOMEM);
 143         }
 144         printk(KERN_INFO "IBLOCK: Created bio_set()\n");
 145         /*
 146          * iblock_check_configfs_dev_params() ensures that ib_dev->ibd_udev_path
 147          * must already have been set in order for echo 1 > $HBA/$DEV/enable to run.
 148          */
 149         printk(KERN_INFO  "IBLOCK: Claiming struct block_device: %s\n",
 150                         ib_dev->ibd_udev_path);
 151
 152         bd = blkdev_get_by_path(ib_dev->ibd_udev_path,
 153                                 FMODE_WRITE|FMODE_READ|FMODE_EXCL, ib_dev);
 154         if (IS_ERR(bd)) {
 155                 ret = PTR_ERR(bd);
 156                 goto failed;
 157         }
 158         /*
 159          * Setup the local scope queue_limits from struct request_queue->limits
 160          * to pass into transport_add_device_to_core_hba() as struct se_dev_limits.
 161          */
 162         q = bdev_get_queue(bd);
 163         limits = &dev_limits.limits;
 164         limits->logical_block_size = bdev_logical_block_size(bd);
 165         limits->max_hw_sectors = queue_max_hw_sectors(q);
 166         limits->max_sectors = queue_max_sectors(q);
 167         dev_limits.hw_queue_depth = q->nr_requests;
 168         dev_limits.queue_depth = q->nr_requests;
 169
 170         ib_dev->ibd_bd = bd;
 171
 172         dev = transport_add_device_to_core_hba(hba,
 173                         &iblock_template, se_dev, dev_flags, ib_dev,
 174                         &dev_limits, "IBLOCK", IBLOCK_VERSION);
 175         if (!(dev))
 176                 goto failed;
 177
 178         /*
 179          * Check if the underlying struct block_device request_queue supports
 180          * the QUEUE_FLAG_DISCARD bit for UNMAP/WRITE_SAME in SCSI + TRIM
 181          * in ATA and we need to set TPE=1
 182          */
 183         if (blk_queue_discard(q)) {
 184                 dev->se_sub_dev->se_dev_attrib.max_unmap_lba_count =
 185                                 q->limits.max_discard_sectors;
 186                 /*
 187                  * Currently hardcoded to 1 in Linux/SCSI code..
 188                  */
 189                 dev->se_sub_dev->se_dev_attrib.max_unmap_block_desc_count = 1;
 190                 dev->se_sub_dev->se_dev_attrib.unmap_granularity =
 191                                 q->limits.discard_granularity;
 192                 dev->se_sub_dev->se_dev_attrib.unmap_granularity_alignment =
 193                                 q->limits.discard_alignment;
 194
 195                 printk(KERN_INFO "IBLOCK: BLOCK Discard support available,"
 196                                 " disabled by default\n");
 197         }
 198
 199         return dev;
 200
 201 failed:
 202         if (ib_dev->ibd_bio_set) {
 203                 bioset_free(ib_dev->ibd_bio_set);
 204                 ib_dev->ibd_bio_set = NULL;
 205         }
 206         ib_dev->ibd_bd = NULL;
 207         return ERR_PTR(ret);
 208 }
 209
 210 static void iblock_free_device(void *p)
 211 {
 212         struct iblock_dev *ib_dev = p;
 213
 214         if (ib_dev->ibd_bd != NULL)
 215                 blkdev_put(ib_dev->ibd_bd, FMODE_WRITE|FMODE_READ|FMODE_EXCL);
 216         if (ib_dev->ibd_bio_set != NULL)
 217                 bioset_free(ib_dev->ibd_bio_set);
 218         kfree(ib_dev);
 219 }
 220
 221 static inline struct iblock_req *IBLOCK_REQ(struct se_task *task)
 222 {
 223         return container_of(task, struct iblock_req, ib_task);
 224 }
 225
 226 static struct se_task *
 227 iblock_alloc_task(struct se_cmd *cmd)
 228 {
 229         struct iblock_req *ib_req;
 230
 231         ib_req = kzalloc(sizeof(struct iblock_req), GFP_KERNEL);
 232         if (!(ib_req)) {
 233                 printk(KERN_ERR "Unable to allocate memory for struct iblock_req\n");
 234                 return NULL;
 235         }
 236
 237         ib_req->ib_dev = cmd->se_dev->dev_ptr;
 238         atomic_set(&ib_req->ib_bio_cnt, 0);
 239         return &ib_req->ib_task;
 240 }
 241
 242 static unsigned long long iblock_emulate_read_cap_with_block_size(
 243         struct se_device *dev,
 244         struct block_device *bd,
 245         struct request_queue *q)
 246 {
 247         unsigned long long blocks_long = (div_u64(i_size_read(bd->bd_inode),
 248                                         bdev_logical_block_size(bd)) - 1);
 249         u32 block_size = bdev_logical_block_size(bd);
 250
 251         if (block_size == dev->se_sub_dev->se_dev_attrib.block_size)
 252                 return blocks_long;
 253
 254         switch (block_size) {
 255         case 4096:
 256                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 257                 case 2048:
 258                         blocks_long <<= 1;
 259                         break;
 260                 case 1024:
 261                         blocks_long <<= 2;
 262                         break;
 263                 case 512:
 264                         blocks_long <<= 3;
 265                 default:
 266                         break;
 267                 }
 268                 break;
 269         case 2048:
 270                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 271                 case 4096:
 272                         blocks_long >>= 1;
 273                         break;
 274                 case 1024:
 275                         blocks_long <<= 1;
 276                         break;
 277                 case 512:
 278                         blocks_long <<= 2;
 279                         break;
 280                 default:
 281                         break;
 282                 }
 283                 break;
 284         case 1024:
 285                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 286                 case 4096:
 287                         blocks_long >>= 2;
 288                         break;
 289                 case 2048:
 290                         blocks_long >>= 1;
 291                         break;
 292                 case 512:
 293                         blocks_long <<= 1;
 294                         break;
 295                 default:
 296                         break;
 297                 }
 298                 break;
 299         case 512:
 300                 switch (dev->se_sub_dev->se_dev_attrib.block_size) {
 301                 case 4096:
 302                         blocks_long >>= 3;
 303                         break;
 304                 case 2048:
 305                         blocks_long >>= 2;
 306                         break;
 307                 case 1024:
 308                         blocks_long >>= 1;
 309                         break;
 310                 default:
 311                         break;
 312                 }
 313                 break;
 314         default:
 315                 break;
 316         }
 317
 318         return blocks_long;
 319 }
 320
 321 /*
 322  * Emulate SYCHRONIZE_CACHE_*
 323  */
 324 static void iblock_emulate_sync_cache(struct se_task *task)
 325 {
 326         struct se_cmd *cmd = task->task_se_cmd;
 327         struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
 328         int immed = (cmd->t_task_cdb[1] & 0x2);
 329         sector_t error_sector;
 330         int ret;
 331
 332         /*
 333          * If the Immediate bit is set, queue up the GOOD response
 334          * for this SYNCHRONIZE_CACHE op
 335          */
 336         if (immed)
 337                 transport_complete_sync_cache(cmd, 1);
 338
 339         /*
 340          * blkdev_issue_flush() does not support a specifying a range, so
 341          * we have to flush the entire cache.
 342          */
 343         ret = blkdev_issue_flush(ib_dev->ibd_bd, GFP_KERNEL, &error_sector);
 344         if (ret != 0) {
 345                 printk(KERN_ERR "IBLOCK: block_issue_flush() failed: %d "
 346                         " error_sector: %llu\n", ret,
 347                         (unsigned long long)error_sector);
 348         }
 349
 350         if (!immed)
 351                 transport_complete_sync_cache(cmd, ret == 0);
 352 }
 353
 354 /*
 355  * Tell TCM Core that we are capable of WriteCache emulation for
 356  * an underlying struct se_device.
 357  */
 358 static int iblock_emulated_write_cache(struct se_device *dev)
 359 {
 360         return 1;
 361 }
 362
 363 static int iblock_emulated_dpo(struct se_device *dev)
 364 {
 365         return 0;
 366 }
 367
 368 /*
 369  * Tell TCM Core that we will be emulating Forced Unit Access (FUA) for WRITEs
 370  * for TYPE_DISK.
 371  */
 372 static int iblock_emulated_fua_write(struct se_device *dev)
 373 {
 374         return 1;
 375 }
 376
 377 static int iblock_emulated_fua_read(struct se_device *dev)
 378 {
 379         return 0;
 380 }
 381
 382 static int iblock_do_task(struct se_task *task)
 383 {
 384         struct se_device *dev = task->task_se_cmd->se_dev;
 385         struct iblock_req *req = IBLOCK_REQ(task);
 386         struct bio *bio = req->ib_bio, *nbio = NULL;
 387         struct blk_plug plug;
 388         int rw;
 389
 390         if (task->task_data_direction == DMA_TO_DEVICE) {
 391                 /*
 392                  * Force data to disk if we pretend to not have a volatile
 393                  * write cache, or the initiator set the Force Unit Access bit.
 394                  */
 395                 if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 396                     (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
 397                      task->task_se_cmd->t_tasks_fua))
 398                         rw = WRITE_FUA;
 399                 else
 400                         rw = WRITE;
 401         } else {
 402                 rw = READ;
 403         }
 404
 405         blk_start_plug(&plug);
 406         while (bio) {
 407                 nbio = bio->bi_next;
 408                 bio->bi_next = NULL;
 409                 DEBUG_IBLOCK("Calling submit_bio() task: %p bio: %p"
 410                         " bio->bi_sector: %llu\n", task, bio, bio->bi_sector);
 411
 412                 submit_bio(rw, bio);
 413                 bio = nbio;
 414         }
 415         blk_finish_plug(&plug);
 416
 417         return PYX_TRANSPORT_SENT_TO_TRANSPORT;
 418 }
 419
 420 static int iblock_do_discard(struct se_device *dev, sector_t lba, u32 range)
 421 {
 422         struct iblock_dev *ibd = dev->dev_ptr;
 423         struct block_device *bd = ibd->ibd_bd;
 424         int barrier = 0;
 425
 426         return blkdev_issue_discard(bd, lba, range, GFP_KERNEL, barrier);
 427 }
 428
 429 static void iblock_free_task(struct se_task *task)
 430 {
 431         struct iblock_req *req = IBLOCK_REQ(task);
 432         struct bio *bio, *hbio = req->ib_bio;
 433         /*
 434          * We only release the bio(s) here if iblock_bio_done() has not called
 435          * bio_put() -> iblock_bio_destructor().
 436          */
 437         while (hbio != NULL) {
 438                 bio = hbio;
 439                 hbio = hbio->bi_next;
 440                 bio->bi_next = NULL;
 441                 bio_put(bio);
 442         }
 443
 444         kfree(req);
 445 }
 446
 447 enum {
 448         Opt_udev_path, Opt_force, Opt_err
 449 };
 450
 451 static match_table_t tokens = {
 452         {Opt_udev_path, "udev_path=%s"},
 453         {Opt_force, "force=%d"},
 454         {Opt_err, NULL}
 455 };
 456
 457 static ssize_t iblock_set_configfs_dev_params(struct se_hba *hba,
 458                                                struct se_subsystem_dev *se_dev,
 459                                                const char *page, ssize_t count)
 460 {
 461         struct iblock_dev *ib_dev = se_dev->se_dev_su_ptr;
 462         char *orig, *ptr, *arg_p, *opts;
 463         substring_t args[MAX_OPT_ARGS];
 464         int ret = 0, token;
 465
 466         opts = kstrdup(page, GFP_KERNEL);
 467         if (!opts)
 468                 return -ENOMEM;
 469
 470         orig = opts;
 471
 472         while ((ptr = strsep(&opts, ",")) != NULL) {
 473                 if (!*ptr)
 474                         continue;
 475
 476                 token = match_token(ptr, tokens, args);
 477                 switch (token) {
 478                 case Opt_udev_path:
 479                         if (ib_dev->ibd_bd) {
 480                                 printk(KERN_ERR "Unable to set udev_path= while"
 481                                         " ib_dev->ibd_bd exists\n");
 482                                 ret = -EEXIST;
 483                                 goto out;
 484                         }
 485                         arg_p = match_strdup(&args[0]);
 486                         if (!arg_p) {
 487                                 ret = -ENOMEM;
 488                                 break;
 489                         }
 490                         snprintf(ib_dev->ibd_udev_path, SE_UDEV_PATH_LEN,
 491                                         "%s", arg_p);
 492                         kfree(arg_p);
 493                         printk(KERN_INFO "IBLOCK: Referencing UDEV path: %s\n",
 494                                         ib_dev->ibd_udev_path);
 495                         ib_dev->ibd_flags |= IBDF_HAS_UDEV_PATH;
 496                         break;
 497                 case Opt_force:
 498                         break;
 499                 default:
 500                         break;
 501                 }
 502         }
 503
 504 out:
 505         kfree(orig);
 506         return (!ret) ? count : ret;
 507 }
 508
 509 static ssize_t iblock_check_configfs_dev_params(
 510         struct se_hba *hba,
 511         struct se_subsystem_dev *se_dev)
 512 {
 513         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 514
 515         if (!(ibd->ibd_flags & IBDF_HAS_UDEV_PATH)) {
 516                 printk(KERN_ERR "Missing udev_path= parameters for IBLOCK\n");
 517                 return -EINVAL;
 518         }
 519
 520         return 0;
 521 }
 522
 523 static ssize_t iblock_show_configfs_dev_params(
 524         struct se_hba *hba,
 525         struct se_subsystem_dev *se_dev,
 526         char *b)
 527 {
 528         struct iblock_dev *ibd = se_dev->se_dev_su_ptr;
 529         struct block_device *bd = ibd->ibd_bd;
 530         char buf[BDEVNAME_SIZE];
 531         ssize_t bl = 0;
 532
 533         if (bd)
 534                 bl += sprintf(b + bl, "iBlock device: %s",
 535                                 bdevname(bd, buf));
 536         if (ibd->ibd_flags & IBDF_HAS_UDEV_PATH) {
 537                 bl += sprintf(b + bl, "  UDEV PATH: %s\n",
 538                                 ibd->ibd_udev_path);
 539         } else
 540                 bl += sprintf(b + bl, "\n");
 541
 542         bl += sprintf(b + bl, "        ");
 543         if (bd) {
 544                 bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
 545                         MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
 546                         "" : (bd->bd_holder == (struct iblock_dev *)ibd) ?
 547                         "CLAIMED: IBLOCK" : "CLAIMED: OS");
 548         } else {
 549                 bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 550         }
 551
 552         return bl;
 553 }
 554
 555 static void iblock_bio_destructor(struct bio *bio)
 556 {
 557         struct se_task *task = bio->bi_private;
 558         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 559
 560         bio_free(bio, ib_dev->ibd_bio_set);
 561 }
 562
 563 static struct bio *iblock_get_bio(
 564         struct se_task *task,
 565         struct iblock_req *ib_req,
 566         struct iblock_dev *ib_dev,
 567         int *ret,
 568         sector_t lba,
 569         u32 sg_num)
 570 {
 571         struct bio *bio;
 572
 573         bio = bio_alloc_bioset(GFP_NOIO, sg_num, ib_dev->ibd_bio_set);
 574         if (!(bio)) {
 575                 printk(KERN_ERR "Unable to allocate memory for bio\n");
 576                 *ret = PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES;
 577                 return NULL;
 578         }
 579
 580         DEBUG_IBLOCK("Allocated bio: %p task_sg_num: %u using ibd_bio_set:"
 581                 " %p\n", bio, task->task_sg_num, ib_dev->ibd_bio_set);
 582         DEBUG_IBLOCK("Allocated bio: %p task_size: %u\n", bio, task->task_size);
 583
 584         bio->bi_bdev = ib_dev->ibd_bd;
 585         bio->bi_private = task;
 586         bio->bi_destructor = iblock_bio_destructor;
 587         bio->bi_end_io = &iblock_bio_done;
 588         bio->bi_sector = lba;
 589         atomic_inc(&ib_req->ib_bio_cnt);
 590
 591         DEBUG_IBLOCK("Set bio->bi_sector: %llu\n", bio->bi_sector);
 592         DEBUG_IBLOCK("Set ib_req->ib_bio_cnt: %d\n",
 593                         atomic_read(&ib_req->ib_bio_cnt));
 594         return bio;
 595 }
 596
 597 static int iblock_map_task_SG(struct se_task *task)
 598 {
 599         struct se_cmd *cmd = task->task_se_cmd;
 600         struct se_device *dev = cmd->se_dev;
 601         struct iblock_dev *ib_dev = task->se_dev->dev_ptr;
 602         struct iblock_req *ib_req = IBLOCK_REQ(task);
 603         struct bio *bio = NULL, *hbio = NULL, *tbio = NULL;
 604         struct scatterlist *sg;
 605         int ret = 0;
 606         u32 i, sg_num = task->task_sg_num;
 607         sector_t block_lba;
 608         /*
 609          * Do starting conversion up from non 512-byte blocksize with
 610          * struct se_task SCSI blocksize into Linux/Block 512 units for BIO.
 611          */
 612         if (dev->se_sub_dev->se_dev_attrib.block_size == 4096)
 613                 block_lba = (task->task_lba << 3);
 614         else if (dev->se_sub_dev->se_dev_attrib.block_size == 2048)
 615                 block_lba = (task->task_lba << 2);
 616         else if (dev->se_sub_dev->se_dev_attrib.block_size == 1024)
 617                 block_lba = (task->task_lba << 1);
 618         else if (dev->se_sub_dev->se_dev_attrib.block_size == 512)
 619                 block_lba = task->task_lba;
 620         else {
 621                 printk(KERN_ERR "Unsupported SCSI -> BLOCK LBA conversion:"
 622                                 " %u\n", dev->se_sub_dev->se_dev_attrib.block_size);
 623                 return PYX_TRANSPORT_LU_COMM_FAILURE;
 624         }
 625
 626         bio = iblock_get_bio(task, ib_req, ib_dev, &ret, block_lba, sg_num);
 627         if (!(bio))
 628                 return ret;
 629
 630         ib_req->ib_bio = bio;
 631         hbio = tbio = bio;
 632         /*
 633          * Use fs/bio.c:bio_add_pages() to setup the bio_vec maplist
 634          * from TCM struct se_mem -> task->task_sg -> struct scatterlist memory.
 635          */
 636         for_each_sg(task->task_sg, sg, task->task_sg_num, i) {
 637                 DEBUG_IBLOCK("task: %p bio: %p Calling bio_add_page(): page:"
 638                         " %p len: %u offset: %u\n", task, bio, sg_page(sg),
 639                                 sg->length, sg->offset);
 640 again:
 641                 ret = bio_add_page(bio, sg_page(sg), sg->length, sg->offset);
 642                 if (ret != sg->length) {
 643
 644                         DEBUG_IBLOCK("*** Set bio->bi_sector: %llu\n",
 645                                         bio->bi_sector);
 646                         DEBUG_IBLOCK("** task->task_size: %u\n",
 647                                         task->task_size);
 648                         DEBUG_IBLOCK("*** bio->bi_max_vecs: %u\n",
 649                                         bio->bi_max_vecs);
 650                         DEBUG_IBLOCK("*** bio->bi_vcnt: %u\n",
 651                                         bio->bi_vcnt);
 652
 653                         bio = iblock_get_bio(task, ib_req, ib_dev, &ret,
 654                                                 block_lba, sg_num);
 655                         if (!(bio))
 656                                 goto fail;
 657
 658                         tbio = tbio->bi_next = bio;
 659                         DEBUG_IBLOCK("-----------------> Added +1 bio: %p to"
 660                                 " list, Going to again\n", bio);
 661                         goto again;
 662                 }
 663                 /* Always in 512 byte units for Linux/Block */
 664                 block_lba += sg->length >> IBLOCK_LBA_SHIFT;
 665                 sg_num--;
 666                 DEBUG_IBLOCK("task: %p bio-add_page() passed!, decremented"
 667                         " sg_num to %u\n", task, sg_num);
 668                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, increased lba"
 669                                 " to %llu\n", task, block_lba);
 670                 DEBUG_IBLOCK("task: %p bio_add_page() passed!, bio->bi_vcnt:"
 671                                 " %u\n", task, bio->bi_vcnt);
 672         }
 673
 674         return 0;
 675 fail:
 676         while (hbio) {
 677                 bio = hbio;
 678                 hbio = hbio->bi_next;
 679                 bio->bi_next = NULL;
 680                 bio_put(bio);
 681         }
 682         return ret;
 683 }
 684
 685 static unsigned char *iblock_get_cdb(struct se_task *task)
 686 {
 687         return IBLOCK_REQ(task)->ib_scsi_cdb;
 688 }
 689
 690 static u32 iblock_get_device_rev(struct se_device *dev)
 691 {
 692         return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
 693 }
 694
 695 static u32 iblock_get_device_type(struct se_device *dev)
 696 {
 697         return TYPE_DISK;
 698 }
 699
 700 static sector_t iblock_get_blocks(struct se_device *dev)
 701 {
 702         struct iblock_dev *ibd = dev->dev_ptr;
 703         struct block_device *bd = ibd->ibd_bd;
 704         struct request_queue *q = bdev_get_queue(bd);
 705
 706         return iblock_emulate_read_cap_with_block_size(dev, bd, q);
 707 }
 708
 709 static void iblock_bio_done(struct bio *bio, int err)
 710 {
 711         struct se_task *task = bio->bi_private;
 712         struct iblock_req *ibr = IBLOCK_REQ(task);
 713         /*
 714          * Set -EIO if !BIO_UPTODATE and the passed is still err=0
 715          */
 716         if (!(test_bit(BIO_UPTODATE, &bio->bi_flags)) && !(err))
 717                 err = -EIO;
 718
 719         if (err != 0) {
 720                 printk(KERN_ERR "test_bit(BIO_UPTODATE) failed for bio: %p,"
 721                         " err: %d\n", bio, err);
 722                 /*
 723                  * Bump the ib_bio_err_cnt and release bio.
 724                  */
 725                 atomic_inc(&ibr->ib_bio_err_cnt);
 726                 smp_mb__after_atomic_inc();
 727                 bio_put(bio);
 728                 /*
 729                  * Wait to complete the task until the last bio as completed.
 730                  */
 731                 if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 732                         return;
 733
 734                 ibr->ib_bio = NULL;
 735                 transport_complete_task(task, 0);
 736                 return;
 737         }
 738         DEBUG_IBLOCK("done[%p] bio: %p task_lba: %llu bio_lba: %llu err=%d\n",
 739                 task, bio, task->task_lba, bio->bi_sector, err);
 740         /*
 741          * bio_put() will call iblock_bio_destructor() to release the bio back
 742          * to ibr->ib_bio_set.
 743          */
 744         bio_put(bio);
 745         /*
 746          * Wait to complete the task until the last bio as completed.
 747          */
 748         if (!(atomic_dec_and_test(&ibr->ib_bio_cnt)))
 749                 return;
 750         /*
 751          * Return GOOD status for task if zero ib_bio_err_cnt exists.
 752          */
 753         ibr->ib_bio = NULL;
 754         transport_complete_task(task, (!atomic_read(&ibr->ib_bio_err_cnt)));
 755 }
 756
 757 static struct se_subsystem_api iblock_template = {
 758         .name                   = "iblock",
 759         .owner                  = THIS_MODULE,
 760         .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
 761         .map_task_SG            = iblock_map_task_SG,
 762         .attach_hba             = iblock_attach_hba,
 763         .detach_hba             = iblock_detach_hba,
 764         .allocate_virtdevice    = iblock_allocate_virtdevice,
 765         .create_virtdevice      = iblock_create_virtdevice,
 766         .free_device            = iblock_free_device,
 767         .dpo_emulated           = iblock_emulated_dpo,
 768         .fua_write_emulated     = iblock_emulated_fua_write,
 769         .fua_read_emulated      = iblock_emulated_fua_read,
 770         .write_cache_emulated   = iblock_emulated_write_cache,
 771         .alloc_task             = iblock_alloc_task,
 772         .do_task                = iblock_do_task,
 773         .do_discard             = iblock_do_discard,
 774         .do_sync_cache          = iblock_emulate_sync_cache,
 775         .free_task              = iblock_free_task,
 776         .check_configfs_dev_params = iblock_check_configfs_dev_params,
 777         .set_configfs_dev_params = iblock_set_configfs_dev_params,
 778         .show_configfs_dev_params = iblock_show_configfs_dev_params,
 779         .get_cdb                = iblock_get_cdb,
 780         .get_device_rev         = iblock_get_device_rev,
 781         .get_device_type        = iblock_get_device_type,
 782         .get_blocks             = iblock_get_blocks,
 783 };
 784
 785 static int __init iblock_module_init(void)
 786 {
 787         return transport_subsystem_register(&iblock_template);
 788 }
 789
 790 static void iblock_module_exit(void)
 791 {
 792         transport_subsystem_release(&iblock_template);
 793 }
 794
 795 MODULE_DESCRIPTION("TCM IBLOCK subsystem plugin");
 796 MODULE_AUTHOR("nab@Linux-iSCSI.org");
 797 MODULE_LICENSE("GPL");
 798
 799 module_init(iblock_module_init);
 800 module_exit(iblock_module_exit);