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 inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
  41 {
  42         return cmd->se_dev->se_sub_dev->se_dev_attrib.block_size * sectors;
  43 }
  44
  45 static int sbc_check_valid_sectors(struct se_cmd *cmd)
  46 {
  47         struct se_device *dev = cmd->se_dev;
  48         unsigned long long end_lba;
  49         u32 sectors;
  50
  51         sectors = cmd->data_length / dev->se_sub_dev->se_dev_attrib.block_size;
  52         end_lba = dev->transport->get_blocks(dev) + 1;
  53
  54         if (cmd->t_task_lba + sectors > end_lba) {
  55                 pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
  56                         cmd->t_task_lba, sectors, end_lba);
  57                 return -EINVAL;
  58         }
  59
  60         return 0;
  61 }
  62
  63 static inline u32 transport_get_sectors_6(unsigned char *cdb)
  64 {
  65         /*
  66          * Use 8-bit sector value.  SBC-3 says:
  67          *
  68          *   A TRANSFER LENGTH field set to zero specifies that 256
  69          *   logical blocks shall be written.  Any other value
  70          *   specifies the number of logical blocks that shall be
  71          *   written.
  72          */
  73         return cdb[4] ? : 256;
  74 }
  75
  76 static inline u32 transport_get_sectors_10(unsigned char *cdb)
  77 {
  78         return (u32)(cdb[7] << 8) + cdb[8];
  79 }
  80
  81 static inline u32 transport_get_sectors_12(unsigned char *cdb)
  82 {
  83         return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
  84 }
  85
  86 static inline u32 transport_get_sectors_16(unsigned char *cdb)
  87 {
  88         return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
  89                     (cdb[12] << 8) + cdb[13];
  90 }
  91
  92 /*
  93  * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
  94  */
  95 static inline u32 transport_get_sectors_32(unsigned char *cdb)
  96 {
  97         return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
  98                     (cdb[30] << 8) + cdb[31];
  99
 100 }
 101
 102 static inline u32 transport_lba_21(unsigned char *cdb)
 103 {
 104         return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
 105 }
 106
 107 static inline u32 transport_lba_32(unsigned char *cdb)
 108 {
 109         return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 110 }
 111
 112 static inline unsigned long long transport_lba_64(unsigned char *cdb)
 113 {
 114         unsigned int __v1, __v2;
 115
 116         __v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
 117         __v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
 118
 119         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 120 }
 121
 122 /*
 123  * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
 124  */
 125 static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
 126 {
 127         unsigned int __v1, __v2;
 128
 129         __v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
 130         __v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
 131
 132         return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
 133 }
 134
 135 static int sbc_write_same_supported(struct se_device *dev,
 136                 unsigned char *flags)
 137 {
 138         if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
 139                 pr_err("WRITE_SAME PBDATA and LBDATA"
 140                         " bits not supported for Block Discard"
 141                         " Emulation\n");
 142                 return -ENOSYS;
 143         }
 144
 145         /*
 146          * Currently for the emulated case we only accept
 147          * tpws with the UNMAP=1 bit set.
 148          */
 149         if (!(flags[0] & 0x08)) {
 150                 pr_err("WRITE_SAME w/o UNMAP bit not"
 151                         " supported for Block Discard Emulation\n");
 152                 return -ENOSYS;
 153         }
 154
 155         return 0;
 156 }
 157
 158 static void xdreadwrite_callback(struct se_cmd *cmd)
 159 {
 160         unsigned char *buf, *addr;
 161         struct scatterlist *sg;
 162         unsigned int offset;
 163         int i;
 164         int count;
 165         /*
 166          * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
 167          *
 168          * 1) read the specified logical block(s);
 169          * 2) transfer logical blocks from the data-out buffer;
 170          * 3) XOR the logical blocks transferred from the data-out buffer with
 171          *    the logical blocks read, storing the resulting XOR data in a buffer;
 172          * 4) if the DISABLE WRITE bit is set to zero, then write the logical
 173          *    blocks transferred from the data-out buffer; and
 174          * 5) transfer the resulting XOR data to the data-in buffer.
 175          */
 176         buf = kmalloc(cmd->data_length, GFP_KERNEL);
 177         if (!buf) {
 178                 pr_err("Unable to allocate xor_callback buf\n");
 179                 return;
 180         }
 181         /*
 182          * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
 183          * into the locally allocated *buf
 184          */
 185         sg_copy_to_buffer(cmd->t_data_sg,
 186                           cmd->t_data_nents,
 187                           buf,
 188                           cmd->data_length);
 189
 190         /*
 191          * Now perform the XOR against the BIDI read memory located at
 192          * cmd->t_mem_bidi_list
 193          */
 194
 195         offset = 0;
 196         for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
 197                 addr = kmap_atomic(sg_page(sg));
 198                 if (!addr)
 199                         goto out;
 200
 201                 for (i = 0; i < sg->length; i++)
 202                         *(addr + sg->offset + i) ^= *(buf + offset + i);
 203
 204                 offset += sg->length;
 205                 kunmap_atomic(addr);
 206         }
 207
 208 out:
 209         kfree(buf);
 210 }
 211
 212 int sbc_parse_cdb(struct se_cmd *cmd, unsigned int *size)
 213 {
 214         struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
 215         struct se_device *dev = cmd->se_dev;
 216         unsigned char *cdb = cmd->t_task_cdb;
 217         u32 sectors = 0;
 218         int ret;
 219
 220         switch (cdb[0]) {
 221         case READ_6:
 222                 sectors = transport_get_sectors_6(cdb);
 223                 cmd->t_task_lba = transport_lba_21(cdb);
 224                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 225                 break;
 226         case READ_10:
 227                 sectors = transport_get_sectors_10(cdb);
 228                 cmd->t_task_lba = transport_lba_32(cdb);
 229                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 230                 break;
 231         case READ_12:
 232                 sectors = transport_get_sectors_12(cdb);
 233                 cmd->t_task_lba = transport_lba_32(cdb);
 234                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 235                 break;
 236         case READ_16:
 237                 sectors = transport_get_sectors_16(cdb);
 238                 cmd->t_task_lba = transport_lba_64(cdb);
 239                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 240                 break;
 241         case WRITE_6:
 242                 sectors = transport_get_sectors_6(cdb);
 243                 cmd->t_task_lba = transport_lba_21(cdb);
 244                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 245                 break;
 246         case WRITE_10:
 247         case WRITE_VERIFY:
 248                 sectors = transport_get_sectors_10(cdb);
 249                 cmd->t_task_lba = transport_lba_32(cdb);
 250                 if (cdb[1] & 0x8)
 251                         cmd->se_cmd_flags |= SCF_FUA;
 252                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 253                 break;
 254         case WRITE_12:
 255                 sectors = transport_get_sectors_12(cdb);
 256                 cmd->t_task_lba = transport_lba_32(cdb);
 257                 if (cdb[1] & 0x8)
 258                         cmd->se_cmd_flags |= SCF_FUA;
 259                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 260                 break;
 261         case WRITE_16:
 262                 sectors = transport_get_sectors_16(cdb);
 263                 cmd->t_task_lba = transport_lba_64(cdb);
 264                 if (cdb[1] & 0x8)
 265                         cmd->se_cmd_flags |= SCF_FUA;
 266                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 267                 break;
 268         case XDWRITEREAD_10:
 269                 if ((cmd->data_direction != DMA_TO_DEVICE) ||
 270                     !(cmd->se_cmd_flags & SCF_BIDI))
 271                         goto out_invalid_cdb_field;
 272                 sectors = transport_get_sectors_10(cdb);
 273
 274                 cmd->t_task_lba = transport_lba_32(cdb);
 275                 cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 276
 277                 /*
 278                  * Setup BIDI XOR callback to be run after I/O completion.
 279                  */
 280                 cmd->transport_complete_callback = &xdreadwrite_callback;
 281                 if (cdb[1] & 0x8)
 282                         cmd->se_cmd_flags |= SCF_FUA;
 283                 break;
 284         case VARIABLE_LENGTH_CMD:
 285         {
 286                 u16 service_action = get_unaligned_be16(&cdb[8]);
 287                 switch (service_action) {
 288                 case XDWRITEREAD_32:
 289                         sectors = transport_get_sectors_32(cdb);
 290
 291                         /*
 292                          * Use WRITE_32 and READ_32 opcodes for the emulated
 293                          * XDWRITE_READ_32 logic.
 294                          */
 295                         cmd->t_task_lba = transport_lba_64_ext(cdb);
 296                         cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
 297
 298                         /*
 299                          * Setup BIDI XOR callback to be run during after I/O
 300                          * completion.
 301                          */
 302                         cmd->transport_complete_callback = &xdreadwrite_callback;
 303                         if (cdb[1] & 0x8)
 304                                 cmd->se_cmd_flags |= SCF_FUA;
 305                         break;
 306                 case WRITE_SAME_32:
 307                         sectors = transport_get_sectors_32(cdb);
 308                         if (!sectors) {
 309                                 pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
 310                                        " supported\n");
 311                                 goto out_invalid_cdb_field;
 312                         }
 313
 314                         *size = sbc_get_size(cmd, 1);
 315                         cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
 316
 317                         if (sbc_write_same_supported(dev, &cdb[10]) < 0)
 318                                 goto out_unsupported_cdb;
 319                         cmd->execute_cmd = target_emulate_write_same;
 320                         break;
 321                 default:
 322                         pr_err("VARIABLE_LENGTH_CMD service action"
 323                                 " 0x%04x not supported\n", service_action);
 324                         goto out_unsupported_cdb;
 325                 }
 326                 break;
 327         }
 328         case READ_CAPACITY:
 329                 *size = READ_CAP_LEN;
 330                 cmd->execute_cmd = target_emulate_readcapacity;
 331                 break;
 332         case SERVICE_ACTION_IN:
 333                 switch (cmd->t_task_cdb[1] & 0x1f) {
 334                 case SAI_READ_CAPACITY_16:
 335                         cmd->execute_cmd = target_emulate_readcapacity_16;
 336                         break;
 337                 default:
 338                         pr_err("Unsupported SA: 0x%02x\n",
 339                                 cmd->t_task_cdb[1] & 0x1f);
 340                         goto out_invalid_cdb_field;
 341                 }
 342                 *size = (cdb[10] << 24) | (cdb[11] << 16) |
 343                        (cdb[12] << 8) | cdb[13];
 344                 break;
 345         case SYNCHRONIZE_CACHE:
 346         case SYNCHRONIZE_CACHE_16:
 347                 /*
 348                  * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
 349                  */
 350                 if (cdb[0] == SYNCHRONIZE_CACHE) {
 351                         sectors = transport_get_sectors_10(cdb);
 352                         cmd->t_task_lba = transport_lba_32(cdb);
 353                 } else {
 354                         sectors = transport_get_sectors_16(cdb);
 355                         cmd->t_task_lba = transport_lba_64(cdb);
 356                 }
 357
 358                 *size = sbc_get_size(cmd, sectors);
 359
 360                 /*
 361                  * Check to ensure that LBA + Range does not exceed past end of
 362                  * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
 363                  */
 364                 if (cmd->t_task_lba || sectors) {
 365                         if (sbc_check_valid_sectors(cmd) < 0)
 366                                 goto out_invalid_cdb_field;
 367                 }
 368                 cmd->execute_cmd = target_emulate_synchronize_cache;
 369                 break;
 370         case UNMAP:
 371                 *size = get_unaligned_be16(&cdb[7]);
 372                 cmd->execute_cmd = target_emulate_unmap;
 373                 break;
 374         case WRITE_SAME_16:
 375                 sectors = transport_get_sectors_16(cdb);
 376                 if (!sectors) {
 377                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 378                         goto out_invalid_cdb_field;
 379                 }
 380
 381                 *size = sbc_get_size(cmd, 1);
 382                 cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
 383
 384                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
 385                         goto out_unsupported_cdb;
 386                 cmd->execute_cmd = target_emulate_write_same;
 387                 break;
 388         case WRITE_SAME:
 389                 sectors = transport_get_sectors_10(cdb);
 390                 if (!sectors) {
 391                         pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
 392                         goto out_invalid_cdb_field;
 393                 }
 394
 395                 *size = sbc_get_size(cmd, 1);
 396                 cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
 397
 398                 /*
 399                  * Follow sbcr26 with WRITE_SAME (10) and check for the existence
 400                  * of byte 1 bit 3 UNMAP instead of original reserved field
 401                  */
 402                 if (sbc_write_same_supported(dev, &cdb[1]) < 0)
 403                         goto out_unsupported_cdb;
 404                 cmd->execute_cmd = target_emulate_write_same;
 405                 break;
 406         case VERIFY:
 407                 *size = 0;
 408                 cmd->execute_cmd = target_emulate_noop;
 409                 break;
 410         default:
 411                 ret = spc_parse_cdb(cmd, size, false);
 412                 if (ret)
 413                         return ret;
 414         }
 415
 416         /* reject any command that we don't have a handler for */
 417         if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && !cmd->execute_cmd)
 418                 goto out_unsupported_cdb;
 419
 420         if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
 421                 if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {
 422                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 423                                 " big sectors %u exceeds fabric_max_sectors:"
 424                                 " %u\n", cdb[0], sectors,
 425                                 su_dev->se_dev_attrib.fabric_max_sectors);
 426                         goto out_invalid_cdb_field;
 427                 }
 428                 if (sectors > su_dev->se_dev_attrib.hw_max_sectors) {
 429                         printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
 430                                 " big sectors %u exceeds backend hw_max_sectors:"
 431                                 " %u\n", cdb[0], sectors,
 432                                 su_dev->se_dev_attrib.hw_max_sectors);
 433                         goto out_invalid_cdb_field;
 434                 }
 435
 436                 *size = sbc_get_size(cmd, sectors);
 437         }
 438
 439         return 0;
 440
 441 out_unsupported_cdb:
 442         cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 443         cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
 444         return -EINVAL;
 445 out_invalid_cdb_field:
 446         cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
 447         cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
 448         return -EINVAL;
 449 }
 450 EXPORT_SYMBOL(sbc_parse_cdb);