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