drivers/target/target_core_sbc.c

   1 /*
   2  * SCSI Block Commands (SBC) parsing and emulation.
   3  *
   4  * Copyright (c) 2002, 2003, 2004, 2005 PyX Technologies, Inc.
   5  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   6  * Copyright (c) 2007-2010 Rising Tide Systems
   7  * Copyright (c) 2008-2010 Linux-iSCSI.org
   8  *
   9  * Nicholas A. Bellinger <nab@kernel.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  */
  25
  26 #include <linux/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/ratelimit.h>
  29 #include <asm/unaligned.h>
  30 #include <scsi/scsi.h>
  31
  32 #include <target/target_core_base.h>
  33 #include <target/target_core_backend.h>
  34 #include <target/target_core_fabric.h>
  35
  36 #include "target_core_internal.h"
  37 #include "target_core_ua.h"
  38
  39
  40 static int sbc_emulate_readcapacity(struct se_cmd *cmd)
  41 {
  42         struct se_device *dev = cmd->se_dev;
  43         unsigned long long blocks_long = dev->transport->get_blocks(dev);
  44         unsigned char *rbuf;
  45         unsigned char buf[8];
  46         u32 blocks;
  47
  48         if (blocks_long >= 0x00000000ffffffff)
  49                 blocks = 0xffffffff;
  50         else
  51                 blocks = (u32)blocks_long;
  52
  53         buf[0] = (blocks >> 24) & 0xff;
  54         buf[1] = (blocks >> 16) & 0xff;
  55         buf[2] = (blocks >> 8) & 0xff;
  56         buf[3] = blocks & 0xff;
  57         buf[4] = (dev->se_sub_dev->se_dev_attrib.block_size >> 24) & 0xff;
  58         buf[5] = (dev->se_sub_dev->se_dev_attrib.block_size >> 16) & 0xff;
  59         buf[6] = (dev->se_sub_dev->se_dev_attrib.block_size >> 8) & 0xff;
  60         buf[7] = dev->se_sub_dev->se_dev_attrib.block_size & 0xff;
  61
  62         rbuf = transport_kmap_data_sg(cmd);
  63         if (rbuf) {
  64                 memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
  65                 transport_kunmap_data_sg(cmd);
  66         }
  67
  68         target_complete_cmd(cmd, GOOD);
  69         return 0;
  70 }
  71
  72 static int 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->se_sub_dev->se_dev_attrib.block_size >> 24) & 0xff;
  89         buf[9] = (dev->se_sub_dev->se_dev_attrib.block_size >> 16) & 0xff;
  90         buf[10] = (dev->se_sub_dev->se_dev_attrib.block_size >> 8) & 0xff;
  91         buf[11] = dev->se_sub_dev->se_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->se_sub_dev->se_dev_attrib.emulate_tpu || dev->se_sub_dev->se_dev_attrib.emulate_tpws)
  97                 buf[14] = 0x80;
  98
  99         rbuf = transport_kmap_data_sg(cmd);
 100         if (rbuf) {
 101                 memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
 102                 transport_kunmap_data_sg(cmd);
 103         }
 104
 105         target_complete_cmd(cmd, GOOD);
 106         return 0;
 107 }
 108
 109 int spc_get_write_same_sectors(struct se_cmd *cmd)
 110 {
 111         u32 num_blocks;
 112
 113         if (cmd->t_task_cdb[0] == WRITE_SAME)
 114                 num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
 115         else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
 116                 num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
 117         else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
 118                 num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
 119
 120         /*
 121          * Use the explicit range when non zero is supplied, otherwise calculate
 122          * the remaining range based on ->get_blocks() - starting LBA.
 123          */
 124         if (num_blocks)
 125                 return num_blocks;
 126
 127         return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
 128                 cmd->t_task_lba + 1;
 129 }
 130 EXPORT_SYMBOL(spc_get_write_same_sectors);
 131
 132 static int sbc_emulate_verify(struct se_cmd *cmd)
 133 {
 134         target_complete_cmd(cmd, GOOD);
 135         return 0;
 136 }
 137
 138 static int sbc_emulate_noop(struct se_cmd *cmd)
 139 {
 140         target_complete_cmd(cmd, GOOD);
 141         return 0;
 142 }
 143
 144 static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
 145 {
 146         return cmd->se_dev->se_sub_dev->se_dev_attrib.block_size * sectors;
 147 }
 148
 149 static int sbc_check_valid_sectors(struct se_cmd *cmd)
 150 {
 151         struct se_device *dev = cmd->se_dev;
 152         unsigned long long end_lba;
 153         u32 sectors;
 154
 155         sectors = cmd->data_length / dev->se_sub_dev->se_dev_attrib.block_size;
 156         end_lba = dev->transport->get_blocks(dev) + 1;
 157
 158         if (cmd->t_task_lba + sectors > end_lba) {
 159                 pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
 160                         cmd->t_task_lba, sectors, end_lba);
 161                 return -EINVAL;
 162         }
 163
 164         return 0;
 165 }
 166
 167 static inline u32 transport_get_sectors_6(unsigned char *cdb)
 168 {
 169         /*
 170          * Use 8-bit sector value.  SBC-3 says:
 171          *
 172          *   A TRANSFER LENGTH field set to zero specifies that 256
 173          *   logical blocks shall be written.  Any other value
 174          *   specifies the number of logical blocks that shall be
 175          *   written.
 176          */
 177         return cdb[4] ? : 256;
 178 }
 179
 180 static inline u32 transport_get_sectors_10(unsigned char *cdb)
 181 {
 182         return (u32)(cdb[7] << 8) + cdb[8];
 183 }
 184
 185 static inline u32 transport_get_sectors_12(unsigned char *cdb)
 186 {
 187         return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
 188 }
 189
 190 static inline u32 transport_get_sectors_16(unsigned char *cdb)
 191 {
 192         return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
 193                     (cdb[12] << 8) + cdb[13];
 194 }
 195
 196 /*
 197  * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
 198  */
 199 static inline u32 transport_get_sectors_32(unsigned char *cdb)
 200 {
 201         return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
 202                     (cdb[30] << 8) + cdb[31];
 203
 204 }
 205
 206 static inline u32 transport_lba_21(unsigned char *cdb)
 207 {
 208         return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
 209 }
 210
 211 static inline u32 transport_lba_32(unsigned char *cdb)
 212 {
 213         return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 214 }
 215
 216 static inline unsigned long long transport_lba_64(unsigned char *cdb)
 217 {
 218         unsigned int __v1, __v2;
 219
 220         __v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 221         __v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
 222
 223         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 224 }
 225
 226 /*
 227  * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
 228  */
 229 static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
 230 {
 231         unsigned int __v1, __v2;
 232
 233         __v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
 234         __v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
 235
 236         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 237 }
 238
 239 static int sbc_write_same_supported(struct se_device *dev,
 240                 unsigned char *flags)
 241 {
 242         if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
 243                 pr_err("WRITE_SAME PBDATA and LBDATA"
 244                         " bits not supported for Block Discard"
 245                         " Emulation\n");
 246                 return -ENOSYS;
 247         }
 248
 249         /*
 250          * Currently for the emulated case we only accept
 251          * tpws with the UNMAP=1 bit set.
 252          */
 253         if (!(flags[0] & 0x08)) {
 254                 pr_err("WRITE_SAME w/o UNMAP bit not"
 255                         " supported for Block Discard Emulation\n");
 256                 return -ENOSYS;
 257         }
 258
 259         return 0;
 260 }
 261
 262 static void xdreadwrite_callback(struct se_cmd *cmd)
 263 {
 264         unsigned char *buf, *addr;
 265         struct scatterlist *sg;
 266         unsigned int offset;
 267         int i;
 268         int count;
 269         /*
 270          * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
 271          *
 272          * 1) read the specified logical block(s);
 273          * 2) transfer logical blocks from the data-out buffer;
 274          * 3) XOR the logical blocks transferred from the data-out buffer with
 275          *    the logical blocks read, storing the resulting XOR data in a buffer;
 276          * 4) if the DISABLE WRITE bit is set to zero, then write the logical
 277          *    blocks transferred from the data-out buffer; and
 278          * 5) transfer the resulting XOR data to the data-in buffer.
 279          */
 280         buf = kmalloc(cmd->data_length, GFP_KERNEL);
 281         if (!buf) {
 282                 pr_err("Unable to allocate xor_callback buf\n");
 283                 return;
 284         }
 285         /*
 286          * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
 287          * into the locally allocated *buf
 288          */
 289         sg_copy_to_buffer(cmd->t_data_sg,
 290                           cmd->t_data_nents,
 291                           buf,
 292                           cmd->data_length);
 293
 294         /*
 295          * Now perform the XOR against the BIDI read memory located at
 296          * cmd->t_mem_bidi_list
 297          */
 298
 299         offset = 0;
 300         for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
 301                 addr = kmap_atomic(sg_page(sg));
 302                 if (!addr)
 303                         goto out;
 304
 305                 for (i = 0; i < sg->length; i++)
 306                         *(addr + sg->offset + i) ^= *(buf + offset + i);
 307
 308                 offset += sg->length;
 309                 kunmap_atomic(addr);
 310         }
 311
 312 out:
 313         kfree(buf);
 314 }
 315
 316 int sbc_parse_cdb(struct se_cmd *cmd, struct spc_ops *ops)
 317 {
 318         struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
 319         struct se_device *dev = cmd->se_dev;
 320         unsigned char *cdb = cmd->t_task_cdb;
 321         unsigned int size;
 322         u32 sectors = 0;
 323         int ret;
 324
 325         switch (cdb[0]) {
 326         case READ_6:
 327                 sectors = transport_get_sectors_6(cdb);
 328                 cmd->t_task_lba = transport_lba_21(cdb);
 329                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 330                 cmd->execute_cmd = ops->execute_rw;
 331                 break;
 332         case READ_10:
 333                 sectors = transport_get_sectors_10(cdb);
 334                 cmd->t_task_lba = transport_lba_32(cdb);
 335                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 336                 cmd->execute_cmd = ops->execute_rw;
 337                 break;
 338         case READ_12:
 339                 sectors = transport_get_sectors_12(cdb);
 340                 cmd->t_task_lba = transport_lba_32(cdb);
 341                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 342                 cmd->execute_cmd = ops->execute_rw;
 343                 break;
 344         case READ_16:
 345                 sectors = transport_get_sectors_16(cdb);
 346                 cmd->t_task_lba = transport_lba_64(cdb);
 347                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 348                 cmd->execute_cmd = ops->execute_rw;
 349                 break;
 350         case WRITE_6:
 351                 sectors = transport_get_sectors_6(cdb);
 352                 cmd->t_task_lba = transport_lba_21(cdb);
 353                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 354                 cmd->execute_cmd = ops->execute_rw;
 355                 break;
 356         case WRITE_10:
 357         case WRITE_VERIFY:
 358                 sectors = transport_get_sectors_10(cdb);
 359                 cmd->t_task_lba = transport_lba_32(cdb);
 360                 if (cdb[1] & 0x8)
 361                         cmd->se_cmd_flags |= SCF_FUA;
 362                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 363                 cmd->execute_cmd = ops->execute_rw;
 364                 break;
 365         case WRITE_12:
 366                 sectors = transport_get_sectors_12(cdb);
 367                 cmd->t_task_lba = transport_lba_32(cdb);
 368                 if (cdb[1] & 0x8)
 369                         cmd->se_cmd_flags |= SCF_FUA;
 370                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 371                 cmd->execute_cmd = ops->execute_rw;
 372                 break;
 373         case WRITE_16:
 374                 sectors = transport_get_sectors_16(cdb);
 375                 cmd->t_task_lba = transport_lba_64(cdb);
 376                 if (cdb[1] & 0x8)
 377                         cmd->se_cmd_flags |= SCF_FUA;
 378                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 379                 cmd->execute_cmd = ops->execute_rw;
 380                 break;
 381         case XDWRITEREAD_10:
 382                 if ((cmd->data_direction != DMA_TO_DEVICE) ||
 383                     !(cmd->se_cmd_flags & SCF_BIDI))
 384                         goto out_invalid_cdb_field;
 385                 sectors = transport_get_sectors_10(cdb);
 386
 387                 cmd->t_task_lba = transport_lba_32(cdb);
 388                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 389
 390                 /*
 391                  * Setup BIDI XOR callback to be run after I/O completion.
 392                  */
 393                 cmd->execute_cmd = ops->execute_rw;
 394                 cmd->transport_complete_callback = &xdreadwrite_callback;
 395                 if (cdb[1] & 0x8)
 396                         cmd->se_cmd_flags |= SCF_FUA;
 397                 break;
 398         case VARIABLE_LENGTH_CMD:
 399         {
 400                 u16 service_action = get_unaligned_be16(&cdb[8]);
 401                 switch (service_action) {
 402                 case XDWRITEREAD_32:
 403                         sectors = transport_get_sectors_32(cdb);
 404
 405                         /*
 406                          * Use WRITE_32 and READ_32 opcodes for the emulated
 407                          * XDWRITE_READ_32 logic.
 408                          */
 409                         cmd->t_task_lba = transport_lba_64_ext(cdb);
 410                         cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 411
 412                         /*
 413                          * Setup BIDI XOR callback to be run during after I/O
 414                          * completion.
 415                          */
 416                         cmd->execute_cmd = ops->execute_rw;
 417                         cmd->transport_complete_callback = &xdreadwrite_callback;
 418                         if (cdb[1] & 0x8)
 419                                 cmd->se_cmd_flags |= SCF_FUA;
 420                         break;
 421                 case WRITE_SAME_32:
 422                         if (!ops->execute_write_same)
 423                                 goto out_unsupported_cdb;
 424
 425                         sectors = transport_get_sectors_32(cdb);
 426                         if (!sectors) {
 427                                 pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
 428                                        " supported\n");
 429                                 goto out_invalid_cdb_field;
 430                         }
 431
 432                         size = sbc_get_size(cmd, 1);
 433                         cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
 434
 435                         if (sbc_write_same_supported(dev, &cdb[10]) < 0)
 436                                 goto out_unsupported_cdb;
 437                         cmd->execute_cmd = ops->execute_write_same;
 438                         break;
 439                 default:
 440                         pr_err("VARIABLE_LENGTH_CMD service action"
 441                                 " 0x%04x not supported\n", service_action);
 442                         goto out_unsupported_cdb;
 443                 }
 444                 break;
 445         }
 446         case READ_CAPACITY:
 447                 size = READ_CAP_LEN;
 448                 cmd->execute_cmd = sbc_emulate_readcapacity;
 449                 break;
 450         case SERVICE_ACTION_IN:
 451                 switch (cmd->t_task_cdb[1] & 0x1f) {
 452                 case SAI_READ_CAPACITY_16:
 453                         cmd->execute_cmd = sbc_emulate_readcapacity_16;
 454                         break;
 455                 default:
 456                         pr_err("Unsupported SA: 0x%02x\n",
 457                                 cmd->t_task_cdb[1] & 0x1f);
 458                         goto out_invalid_cdb_field;
 459                 }
 460                 size = (cdb[10] << 24) | (cdb[11] << 16) |
 461                        (cdb[12] << 8) | cdb[13];
 462                 break;
 463         case SYNCHRONIZE_CACHE:
 464         case SYNCHRONIZE_CACHE_16:
 465                 if (!ops->execute_sync_cache)
 466                         goto out_unsupported_cdb;
 467
 468                 /*
 469                  * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
 470                  */
 471                 if (cdb[0] == SYNCHRONIZE_CACHE) {
 472                         sectors = transport_get_sectors_10(cdb);
 473                         cmd->t_task_lba = transport_lba_32(cdb);
 474                 } else {
 475                         sectors = transport_get_sectors_16(cdb);
 476                         cmd->t_task_lba = transport_lba_64(cdb);
 477                 }
 478
 479                 size = sbc_get_size(cmd, sectors);
 480
 481                 /*
 482                  * Check to ensure that LBA + Range does not exceed past end of
 483                  * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
 484                  */
 485                 if (cmd->t_task_lba || sectors) {
 486                         if (sbc_check_valid_sectors(cmd) < 0)
 487                                 goto out_invalid_cdb_field;
 488                 }
 489                 cmd->execute_cmd = ops->execute_sync_cache;
 490                 break;
 491         case UNMAP:
 492                 if (!ops->execute_unmap)
 493                         goto out_unsupported_cdb;
 494
 495                 size = get_unaligned_be16(&cdb[7]);
 496                 cmd->execute_cmd = ops->execute_unmap;
 497                 break;
 498         case WRITE_SAME_16:
 499                 if (!ops->execute_write_same)
 500                         goto out_unsupported_cdb;
 501
 502                 sectors = transport_get_sectors_16(cdb);
 503                 if (!sectors) {
 504                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 505                         goto out_invalid_cdb_field;
 506                 }
 507
 508                 size = sbc_get_size(cmd, 1);
 509                 cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
 510
 511                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
 512                         goto out_unsupported_cdb;
 513                 cmd->execute_cmd = ops->execute_write_same;
 514                 break;
 515         case WRITE_SAME:
 516                 if (!ops->execute_write_same)
 517                         goto out_unsupported_cdb;
 518
 519                 sectors = transport_get_sectors_10(cdb);
 520                 if (!sectors) {
 521                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 522                         goto out_invalid_cdb_field;
 523                 }
 524
 525                 size = sbc_get_size(cmd, 1);
 526                 cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
 527
 528                 /*
 529                  * Follow sbcr26 with WRITE_SAME (10) and check for the existence
 530                  * of byte 1 bit 3 UNMAP instead of original reserved field
 531                  */
 532                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
 533                         goto out_unsupported_cdb;
 534                 cmd->execute_cmd = ops->execute_write_same;
 535                 break;
 536         case VERIFY:
 537                 size = 0;
 538                 cmd->execute_cmd = sbc_emulate_verify;
 539                 break;
 540         case REZERO_UNIT:
 541         case SEEK_6:
 542         case SEEK_10:
 543                 /*
 544                  * There are still clients out there which use these old SCSI-2
 545                  * commands. This mainly happens when running VMs with legacy
 546                  * guest systems, connected via SCSI command pass-through to
 547                  * iSCSI targets. Make them happy and return status GOOD.
 548                  */
 549                 size = 0;
 550                 cmd->execute_cmd = sbc_emulate_noop;
 551                 break;
 552         default:
 553                 ret = spc_parse_cdb(cmd, &size);
 554                 if (ret)
 555                         return ret;
 556         }
 557
 558         /* reject any command that we don't have a handler for */
 559         if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && !cmd->execute_cmd)
 560                 goto out_unsupported_cdb;
 561
 562         if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
 563                 unsigned long long end_lba;
 564
 565                 if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {
 566                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 567                                 " big sectors %u exceeds fabric_max_sectors:"
 568                                 " %u\n", cdb[0], sectors,
 569                                 su_dev->se_dev_attrib.fabric_max_sectors);
 570                         goto out_invalid_cdb_field;
 571                 }
 572                 if (sectors > su_dev->se_dev_attrib.hw_max_sectors) {
 573                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 574                                 " big sectors %u exceeds backend hw_max_sectors:"
 575                                 " %u\n", cdb[0], sectors,
 576                                 su_dev->se_dev_attrib.hw_max_sectors);
 577                         goto out_invalid_cdb_field;
 578                 }
 579
 580                 end_lba = dev->transport->get_blocks(dev) + 1;
 581                 if (cmd->t_task_lba + sectors > end_lba) {
 582                         pr_err("cmd exceeds last lba %llu "
 583                                 "(lba %llu, sectors %u)\n",
 584                                 end_lba, cmd->t_task_lba, sectors);
 585                         goto out_invalid_cdb_field;
 586                 }
 587
 588                 size = sbc_get_size(cmd, sectors);
 589         }
 590
 591         ret = target_cmd_size_check(cmd, size);
 592         if (ret < 0)
 593                 return ret;
 594
 595         return 0;
 596
 597 out_unsupported_cdb:
 598         cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 599         cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
 600         return -EINVAL;
 601 out_invalid_cdb_field:
 602         cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 603         cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
 604         return -EINVAL;
 605 }
 606 EXPORT_SYMBOL(sbc_parse_cdb);