drivers/target/target_core_sbc.c

   1 /*
   2  * SCSI Block Commands (SBC) parsing and emulation.
   3  *
   4  * (c) Copyright 2002-2012 RisingTide Systems LLC.
   5  *
   6  * Nicholas A. Bellinger <nab@kernel.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/ratelimit.h>
  26 #include <asm/unaligned.h>
  27 #include <scsi/scsi.h>
  28
  29 #include <target/target_core_base.h>
  30 #include <target/target_core_backend.h>
  31 #include <target/target_core_fabric.h>
  32
  33 #include "target_core_internal.h"
  34 #include "target_core_ua.h"
  35
  36
  37 static sense_reason_t
  38 sbc_emulate_readcapacity(struct se_cmd *cmd)
  39 {
  40         struct se_device *dev = cmd->se_dev;
  41         unsigned long long blocks_long = dev->transport->get_blocks(dev);
  42         unsigned char *rbuf;
  43         unsigned char buf[8];
  44         u32 blocks;
  45
  46         if (blocks_long >= 0x00000000ffffffff)
  47                 blocks = 0xffffffff;
  48         else
  49                 blocks = (u32)blocks_long;
  50
  51         buf[0] = (blocks >> 24) & 0xff;
  52         buf[1] = (blocks >> 16) & 0xff;
  53         buf[2] = (blocks >> 8) & 0xff;
  54         buf[3] = blocks & 0xff;
  55         buf[4] = (dev->dev_attrib.block_size >> 24) & 0xff;
  56         buf[5] = (dev->dev_attrib.block_size >> 16) & 0xff;
  57         buf[6] = (dev->dev_attrib.block_size >> 8) & 0xff;
  58         buf[7] = dev->dev_attrib.block_size & 0xff;
  59
  60         rbuf = transport_kmap_data_sg(cmd);
  61         if (rbuf) {
  62                 memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
  63                 transport_kunmap_data_sg(cmd);
  64         }
  65
  66         target_complete_cmd(cmd, GOOD);
  67         return 0;
  68 }
  69
  70 static sense_reason_t
  71 sbc_emulate_readcapacity_16(struct se_cmd *cmd)
  72 {
  73         struct se_device *dev = cmd->se_dev;
  74         unsigned char *rbuf;
  75         unsigned char buf[32];
  76         unsigned long long blocks = dev->transport->get_blocks(dev);
  77
  78         memset(buf, 0, sizeof(buf));
  79         buf[0] = (blocks >> 56) & 0xff;
  80         buf[1] = (blocks >> 48) & 0xff;
  81         buf[2] = (blocks >> 40) & 0xff;
  82         buf[3] = (blocks >> 32) & 0xff;
  83         buf[4] = (blocks >> 24) & 0xff;
  84         buf[5] = (blocks >> 16) & 0xff;
  85         buf[6] = (blocks >> 8) & 0xff;
  86         buf[7] = blocks & 0xff;
  87         buf[8] = (dev->dev_attrib.block_size >> 24) & 0xff;
  88         buf[9] = (dev->dev_attrib.block_size >> 16) & 0xff;
  89         buf[10] = (dev->dev_attrib.block_size >> 8) & 0xff;
  90         buf[11] = dev->dev_attrib.block_size & 0xff;
  91         /*
  92          * Set Thin Provisioning Enable bit following sbc3r22 in section
  93          * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
  94          */
  95         if (dev->dev_attrib.emulate_tpu || dev->dev_attrib.emulate_tpws)
  96                 buf[14] = 0x80;
  97
  98         rbuf = transport_kmap_data_sg(cmd);
  99         if (rbuf) {
 100                 memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
 101                 transport_kunmap_data_sg(cmd);
 102         }
 103
 104         target_complete_cmd(cmd, GOOD);
 105         return 0;
 106 }
 107
 108 sector_t sbc_get_write_same_sectors(struct se_cmd *cmd)
 109 {
 110         u32 num_blocks;
 111
 112         if (cmd->t_task_cdb[0] == WRITE_SAME)
 113                 num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
 114         else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
 115                 num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
 116         else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
 117                 num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
 118
 119         /*
 120          * Use the explicit range when non zero is supplied, otherwise calculate
 121          * the remaining range based on ->get_blocks() - starting LBA.
 122          */
 123         if (num_blocks)
 124                 return num_blocks;
 125
 126         return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
 127                 cmd->t_task_lba + 1;
 128 }
 129 EXPORT_SYMBOL(sbc_get_write_same_sectors);
 130
 131 static sense_reason_t
 132 sbc_emulate_noop(struct se_cmd *cmd)
 133 {
 134         target_complete_cmd(cmd, GOOD);
 135         return 0;
 136 }
 137
 138 static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
 139 {
 140         return cmd->se_dev->dev_attrib.block_size * sectors;
 141 }
 142
 143 static int sbc_check_valid_sectors(struct se_cmd *cmd)
 144 {
 145         struct se_device *dev = cmd->se_dev;
 146         unsigned long long end_lba;
 147         u32 sectors;
 148
 149         sectors = cmd->data_length / dev->dev_attrib.block_size;
 150         end_lba = dev->transport->get_blocks(dev) + 1;
 151
 152         if (cmd->t_task_lba + sectors > end_lba) {
 153                 pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
 154                         cmd->t_task_lba, sectors, end_lba);
 155                 return -EINVAL;
 156         }
 157
 158         return 0;
 159 }
 160
 161 static inline u32 transport_get_sectors_6(unsigned char *cdb)
 162 {
 163         /*
 164          * Use 8-bit sector value.  SBC-3 says:
 165          *
 166          *   A TRANSFER LENGTH field set to zero specifies that 256
 167          *   logical blocks shall be written.  Any other value
 168          *   specifies the number of logical blocks that shall be
 169          *   written.
 170          */
 171         return cdb[4] ? : 256;
 172 }
 173
 174 static inline u32 transport_get_sectors_10(unsigned char *cdb)
 175 {
 176         return (u32)(cdb[7] << 8) + cdb[8];
 177 }
 178
 179 static inline u32 transport_get_sectors_12(unsigned char *cdb)
 180 {
 181         return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
 182 }
 183
 184 static inline u32 transport_get_sectors_16(unsigned char *cdb)
 185 {
 186         return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
 187                     (cdb[12] << 8) + cdb[13];
 188 }
 189
 190 /*
 191  * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
 192  */
 193 static inline u32 transport_get_sectors_32(unsigned char *cdb)
 194 {
 195         return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
 196                     (cdb[30] << 8) + cdb[31];
 197
 198 }
 199
 200 static inline u32 transport_lba_21(unsigned char *cdb)
 201 {
 202         return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
 203 }
 204
 205 static inline u32 transport_lba_32(unsigned char *cdb)
 206 {
 207         return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 208 }
 209
 210 static inline unsigned long long transport_lba_64(unsigned char *cdb)
 211 {
 212         unsigned int __v1, __v2;
 213
 214         __v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 215         __v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
 216
 217         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 218 }
 219
 220 /*
 221  * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
 222  */
 223 static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
 224 {
 225         unsigned int __v1, __v2;
 226
 227         __v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
 228         __v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
 229
 230         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 231 }
 232
 233 static sense_reason_t
 234 sbc_setup_write_same(struct se_cmd *cmd, unsigned char *flags, struct sbc_ops *ops)
 235 {
 236         unsigned int sectors = sbc_get_write_same_sectors(cmd);
 237
 238         if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
 239                 pr_err("WRITE_SAME PBDATA and LBDATA"
 240                         " bits not supported for Block Discard"
 241                         " Emulation\n");
 242                 return TCM_UNSUPPORTED_SCSI_OPCODE;
 243         }
 244         if (sectors > cmd->se_dev->dev_attrib.max_write_same_len) {
 245                 pr_warn("WRITE_SAME sectors: %u exceeds max_write_same_len: %u\n",
 246                         sectors, cmd->se_dev->dev_attrib.max_write_same_len);
 247                 return TCM_INVALID_CDB_FIELD;
 248         }
 249         /*
 250          * Special case for WRITE_SAME w/ UNMAP=1 that ends up getting
 251          * translated into block discard requests within backend code.
 252          */
 253         if (flags[0] & 0x08) {
 254                 if (!ops->execute_write_same_unmap)
 255                         return TCM_UNSUPPORTED_SCSI_OPCODE;
 256
 257                 cmd->execute_cmd = ops->execute_write_same_unmap;
 258                 return 0;
 259         }
 260         if (!ops->execute_write_same)
 261                 return TCM_UNSUPPORTED_SCSI_OPCODE;
 262
 263         cmd->execute_cmd = ops->execute_write_same;
 264         return 0;
 265 }
 266
 267 static void xdreadwrite_callback(struct se_cmd *cmd)
 268 {
 269         unsigned char *buf, *addr;
 270         struct scatterlist *sg;
 271         unsigned int offset;
 272         int i;
 273         int count;
 274         /*
 275          * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
 276          *
 277          * 1) read the specified logical block(s);
 278          * 2) transfer logical blocks from the data-out buffer;
 279          * 3) XOR the logical blocks transferred from the data-out buffer with
 280          *    the logical blocks read, storing the resulting XOR data in a buffer;
 281          * 4) if the DISABLE WRITE bit is set to zero, then write the logical
 282          *    blocks transferred from the data-out buffer; and
 283          * 5) transfer the resulting XOR data to the data-in buffer.
 284          */
 285         buf = kmalloc(cmd->data_length, GFP_KERNEL);
 286         if (!buf) {
 287                 pr_err("Unable to allocate xor_callback buf\n");
 288                 return;
 289         }
 290         /*
 291          * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
 292          * into the locally allocated *buf
 293          */
 294         sg_copy_to_buffer(cmd->t_data_sg,
 295                           cmd->t_data_nents,
 296                           buf,
 297                           cmd->data_length);
 298
 299         /*
 300          * Now perform the XOR against the BIDI read memory located at
 301          * cmd->t_mem_bidi_list
 302          */
 303
 304         offset = 0;
 305         for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
 306                 addr = kmap_atomic(sg_page(sg));
 307                 if (!addr)
 308                         goto out;
 309
 310                 for (i = 0; i < sg->length; i++)
 311                         *(addr + sg->offset + i) ^= *(buf + offset + i);
 312
 313                 offset += sg->length;
 314                 kunmap_atomic(addr);
 315         }
 316
 317 out:
 318         kfree(buf);
 319 }
 320
 321 sense_reason_t
 322 sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops)
 323 {
 324         struct se_device *dev = cmd->se_dev;
 325         unsigned char *cdb = cmd->t_task_cdb;
 326         unsigned int size;
 327         u32 sectors = 0;
 328         sense_reason_t ret;
 329
 330         switch (cdb[0]) {
 331         case READ_6:
 332                 sectors = transport_get_sectors_6(cdb);
 333                 cmd->t_task_lba = transport_lba_21(cdb);
 334                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 335                 cmd->execute_cmd = ops->execute_rw;
 336                 break;
 337         case READ_10:
 338                 sectors = transport_get_sectors_10(cdb);
 339                 cmd->t_task_lba = transport_lba_32(cdb);
 340                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 341                 cmd->execute_cmd = ops->execute_rw;
 342                 break;
 343         case READ_12:
 344                 sectors = transport_get_sectors_12(cdb);
 345                 cmd->t_task_lba = transport_lba_32(cdb);
 346                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 347                 cmd->execute_cmd = ops->execute_rw;
 348                 break;
 349         case READ_16:
 350                 sectors = transport_get_sectors_16(cdb);
 351                 cmd->t_task_lba = transport_lba_64(cdb);
 352                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 353                 cmd->execute_cmd = ops->execute_rw;
 354                 break;
 355         case WRITE_6:
 356                 sectors = transport_get_sectors_6(cdb);
 357                 cmd->t_task_lba = transport_lba_21(cdb);
 358                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 359                 cmd->execute_cmd = ops->execute_rw;
 360                 break;
 361         case WRITE_10:
 362         case WRITE_VERIFY:
 363                 sectors = transport_get_sectors_10(cdb);
 364                 cmd->t_task_lba = transport_lba_32(cdb);
 365                 if (cdb[1] & 0x8)
 366                         cmd->se_cmd_flags |= SCF_FUA;
 367                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 368                 cmd->execute_cmd = ops->execute_rw;
 369                 break;
 370         case WRITE_12:
 371                 sectors = transport_get_sectors_12(cdb);
 372                 cmd->t_task_lba = transport_lba_32(cdb);
 373                 if (cdb[1] & 0x8)
 374                         cmd->se_cmd_flags |= SCF_FUA;
 375                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 376                 cmd->execute_cmd = ops->execute_rw;
 377                 break;
 378         case WRITE_16:
 379                 sectors = transport_get_sectors_16(cdb);
 380                 cmd->t_task_lba = transport_lba_64(cdb);
 381                 if (cdb[1] & 0x8)
 382                         cmd->se_cmd_flags |= SCF_FUA;
 383                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 384                 cmd->execute_cmd = ops->execute_rw;
 385                 break;
 386         case XDWRITEREAD_10:
 387                 if (cmd->data_direction != DMA_TO_DEVICE ||
 388                     !(cmd->se_cmd_flags & SCF_BIDI))
 389                         return TCM_INVALID_CDB_FIELD;
 390                 sectors = transport_get_sectors_10(cdb);
 391
 392                 cmd->t_task_lba = transport_lba_32(cdb);
 393                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 394
 395                 /*
 396                  * Setup BIDI XOR callback to be run after I/O completion.
 397                  */
 398                 cmd->execute_cmd = ops->execute_rw;
 399                 cmd->transport_complete_callback = &xdreadwrite_callback;
 400                 if (cdb[1] & 0x8)
 401                         cmd->se_cmd_flags |= SCF_FUA;
 402                 break;
 403         case VARIABLE_LENGTH_CMD:
 404         {
 405                 u16 service_action = get_unaligned_be16(&cdb[8]);
 406                 switch (service_action) {
 407                 case XDWRITEREAD_32:
 408                         sectors = transport_get_sectors_32(cdb);
 409
 410                         /*
 411                          * Use WRITE_32 and READ_32 opcodes for the emulated
 412                          * XDWRITE_READ_32 logic.
 413                          */
 414                         cmd->t_task_lba = transport_lba_64_ext(cdb);
 415                         cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 416
 417                         /*
 418                          * Setup BIDI XOR callback to be run during after I/O
 419                          * completion.
 420                          */
 421                         cmd->execute_cmd = ops->execute_rw;
 422                         cmd->transport_complete_callback = &xdreadwrite_callback;
 423                         if (cdb[1] & 0x8)
 424                                 cmd->se_cmd_flags |= SCF_FUA;
 425                         break;
 426                 case WRITE_SAME_32:
 427                         sectors = transport_get_sectors_32(cdb);
 428                         if (!sectors) {
 429                                 pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
 430                                        " supported\n");
 431                                 return TCM_INVALID_CDB_FIELD;
 432                         }
 433
 434                         size = sbc_get_size(cmd, 1);
 435                         cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
 436
 437                         ret = sbc_setup_write_same(cmd, &cdb[10], ops);
 438                         if (ret)
 439                                 return ret;
 440                         break;
 441                 default:
 442                         pr_err("VARIABLE_LENGTH_CMD service action"
 443                                 " 0x%04x not supported\n", service_action);
 444                         return TCM_UNSUPPORTED_SCSI_OPCODE;
 445                 }
 446                 break;
 447         }
 448         case READ_CAPACITY:
 449                 size = READ_CAP_LEN;
 450                 cmd->execute_cmd = sbc_emulate_readcapacity;
 451                 break;
 452         case SERVICE_ACTION_IN:
 453                 switch (cmd->t_task_cdb[1] & 0x1f) {
 454                 case SAI_READ_CAPACITY_16:
 455                         cmd->execute_cmd = sbc_emulate_readcapacity_16;
 456                         break;
 457                 default:
 458                         pr_err("Unsupported SA: 0x%02x\n",
 459                                 cmd->t_task_cdb[1] & 0x1f);
 460                         return TCM_INVALID_CDB_FIELD;
 461                 }
 462                 size = (cdb[10] << 24) | (cdb[11] << 16) |
 463                        (cdb[12] << 8) | cdb[13];
 464                 break;
 465         case SYNCHRONIZE_CACHE:
 466         case SYNCHRONIZE_CACHE_16:
 467                 if (!ops->execute_sync_cache) {
 468                         size = 0;
 469                         cmd->execute_cmd = sbc_emulate_noop;
 470                         break;
 471                 }
 472
 473                 /*
 474                  * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
 475                  */
 476                 if (cdb[0] == SYNCHRONIZE_CACHE) {
 477                         sectors = transport_get_sectors_10(cdb);
 478                         cmd->t_task_lba = transport_lba_32(cdb);
 479                 } else {
 480                         sectors = transport_get_sectors_16(cdb);
 481                         cmd->t_task_lba = transport_lba_64(cdb);
 482                 }
 483
 484                 size = sbc_get_size(cmd, sectors);
 485
 486                 /*
 487                  * Check to ensure that LBA + Range does not exceed past end of
 488                  * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
 489                  */
 490                 if (cmd->t_task_lba || sectors) {
 491                         if (sbc_check_valid_sectors(cmd) < 0)
 492                                 return TCM_ADDRESS_OUT_OF_RANGE;
 493                 }
 494                 cmd->execute_cmd = ops->execute_sync_cache;
 495                 break;
 496         case UNMAP:
 497                 if (!ops->execute_unmap)
 498                         return TCM_UNSUPPORTED_SCSI_OPCODE;
 499
 500                 size = get_unaligned_be16(&cdb[7]);
 501                 cmd->execute_cmd = ops->execute_unmap;
 502                 break;
 503         case WRITE_SAME_16:
 504                 sectors = transport_get_sectors_16(cdb);
 505                 if (!sectors) {
 506                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 507                         return TCM_INVALID_CDB_FIELD;
 508                 }
 509
 510                 size = sbc_get_size(cmd, 1);
 511                 cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
 512
 513                 ret = sbc_setup_write_same(cmd, &cdb[1], ops);
 514                 if (ret)
 515                         return ret;
 516                 break;
 517         case WRITE_SAME:
 518                 sectors = transport_get_sectors_10(cdb);
 519                 if (!sectors) {
 520                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 521                         return TCM_INVALID_CDB_FIELD;
 522                 }
 523
 524                 size = sbc_get_size(cmd, 1);
 525                 cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
 526
 527                 /*
 528                  * Follow sbcr26 with WRITE_SAME (10) and check for the existence
 529                  * of byte 1 bit 3 UNMAP instead of original reserved field
 530                  */
 531                 ret = sbc_setup_write_same(cmd, &cdb[1], ops);
 532                 if (ret)
 533                         return ret;
 534                 break;
 535         case VERIFY:
 536                 size = 0;
 537                 cmd->execute_cmd = sbc_emulate_noop;
 538                 break;
 539         case REZERO_UNIT:
 540         case SEEK_6:
 541         case SEEK_10:
 542                 /*
 543                  * There are still clients out there which use these old SCSI-2
 544                  * commands. This mainly happens when running VMs with legacy
 545                  * guest systems, connected via SCSI command pass-through to
 546                  * iSCSI targets. Make them happy and return status GOOD.
 547                  */
 548                 size = 0;
 549                 cmd->execute_cmd = sbc_emulate_noop;
 550                 break;
 551         default:
 552                 ret = spc_parse_cdb(cmd, &size);
 553                 if (ret)
 554                         return ret;
 555         }
 556
 557         /* reject any command that we don't have a handler for */
 558         if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && !cmd->execute_cmd)
 559                 return TCM_UNSUPPORTED_SCSI_OPCODE;
 560
 561         if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
 562                 unsigned long long end_lba;
 563
 564                 if (sectors > dev->dev_attrib.fabric_max_sectors) {
 565                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 566                                 " big sectors %u exceeds fabric_max_sectors:"
 567                                 " %u\n", cdb[0], sectors,
 568                                 dev->dev_attrib.fabric_max_sectors);
 569                         return TCM_INVALID_CDB_FIELD;
 570                 }
 571                 if (sectors > dev->dev_attrib.hw_max_sectors) {
 572                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 573                                 " big sectors %u exceeds backend hw_max_sectors:"
 574                                 " %u\n", cdb[0], sectors,
 575                                 dev->dev_attrib.hw_max_sectors);
 576                         return TCM_INVALID_CDB_FIELD;
 577                 }
 578
 579                 end_lba = dev->transport->get_blocks(dev) + 1;
 580                 if (cmd->t_task_lba + sectors > end_lba) {
 581                         pr_err("cmd exceeds last lba %llu "
 582                                 "(lba %llu, sectors %u)\n",
 583                                 end_lba, cmd->t_task_lba, sectors);
 584                         return TCM_INVALID_CDB_FIELD;
 585                 }
 586
 587                 size = sbc_get_size(cmd, sectors);
 588         }
 589
 590         return target_cmd_size_check(cmd, size);
 591 }
 592 EXPORT_SYMBOL(sbc_parse_cdb);
 593
 594 u32 sbc_get_device_type(struct se_device *dev)
 595 {
 596         return TYPE_DISK;
 597 }
 598 EXPORT_SYMBOL(sbc_get_device_type);