drivers/scsi/sd_dif.c

   1 /*
   2  * sd_dif.c - SCSI Data Integrity Field
   3  *
   4  * Copyright (C) 2007, 2008 Oracle Corporation
   5  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version
   9  * 2 as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; see the file COPYING.  If not, write to
  18  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  19  * USA.
  20  *
  21  */
  22
  23 #include <linux/blkdev.h>
  24 #include <linux/crc-t10dif.h>
  25
  26 #include <scsi/scsi.h>
  27 #include <scsi/scsi_cmnd.h>
  28 #include <scsi/scsi_dbg.h>
  29 #include <scsi/scsi_device.h>
  30 #include <scsi/scsi_driver.h>
  31 #include <scsi/scsi_eh.h>
  32 #include <scsi/scsi_host.h>
  33 #include <scsi/scsi_ioctl.h>
  34 #include <scsi/scsicam.h>
  35
  36 #include <net/checksum.h>
  37
  38 #include "sd.h"
  39
  40 typedef __u16 (csum_fn) (void *, unsigned int);
  41
  42 static __u16 sd_dif_crc_fn(void *data, unsigned int len)
  43 {
  44         return cpu_to_be16(crc_t10dif(data, len));
  45 }
  46
  47 static __u16 sd_dif_ip_fn(void *data, unsigned int len)
  48 {
  49         return ip_compute_csum(data, len);
  50 }
  51
  52 /*
  53  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
  54  * 16 bit app tag, 32 bit reference tag.
  55  */
  56 static void sd_dif_type1_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
  57 {
  58         void *buf = bix->data_buf;
  59         struct sd_dif_tuple *sdt = bix->prot_buf;
  60         sector_t sector = bix->sector;
  61         unsigned int i;
  62
  63         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
  64                 sdt->guard_tag = fn(buf, bix->sector_size);
  65                 sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
  66                 sdt->app_tag = 0;
  67
  68                 buf += bix->sector_size;
  69                 sector++;
  70         }
  71 }
  72
  73 static void sd_dif_type1_generate_crc(struct blk_integrity_exchg *bix)
  74 {
  75         sd_dif_type1_generate(bix, sd_dif_crc_fn);
  76 }
  77
  78 static void sd_dif_type1_generate_ip(struct blk_integrity_exchg *bix)
  79 {
  80         sd_dif_type1_generate(bix, sd_dif_ip_fn);
  81 }
  82
  83 static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
  84 {
  85         void *buf = bix->data_buf;
  86         struct sd_dif_tuple *sdt = bix->prot_buf;
  87         sector_t sector = bix->sector;
  88         unsigned int i;
  89         __u16 csum;
  90
  91         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
  92                 /* Unwritten sectors */
  93                 if (sdt->app_tag == 0xffff)
  94                         return 0;
  95
  96                 /* Bad ref tag received from disk */
  97                 if (sdt->ref_tag == 0xffffffff) {
  98                         printk(KERN_ERR
  99                                "%s: bad phys ref tag on sector %lu\n",
 100                                bix->disk_name, (unsigned long)sector);
 101                         return -EIO;
 102                 }
 103
 104                 if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
 105                         printk(KERN_ERR
 106                                "%s: ref tag error on sector %lu (rcvd %u)\n",
 107                                bix->disk_name, (unsigned long)sector,
 108                                be32_to_cpu(sdt->ref_tag));
 109                         return -EIO;
 110                 }
 111
 112                 csum = fn(buf, bix->sector_size);
 113
 114                 if (sdt->guard_tag != csum) {
 115                         printk(KERN_ERR "%s: guard tag error on sector %lu " \
 116                                "(rcvd %04x, data %04x)\n", bix->disk_name,
 117                                (unsigned long)sector,
 118                                be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
 119                         return -EIO;
 120                 }
 121
 122                 buf += bix->sector_size;
 123                 sector++;
 124         }
 125
 126         return 0;
 127 }
 128
 129 static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
 130 {
 131         return sd_dif_type1_verify(bix, sd_dif_crc_fn);
 132 }
 133
 134 static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
 135 {
 136         return sd_dif_type1_verify(bix, sd_dif_ip_fn);
 137 }
 138
 139 /*
 140  * Functions for interleaving and deinterleaving application tags
 141  */
 142 static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
 143 {
 144         struct sd_dif_tuple *sdt = prot;
 145         u8 *tag = tag_buf;
 146         unsigned int i, j;
 147
 148         for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
 149                 sdt->app_tag = tag[j] << 8 | tag[j+1];
 150                 BUG_ON(sdt->app_tag == 0xffff);
 151         }
 152 }
 153
 154 static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
 155 {
 156         struct sd_dif_tuple *sdt = prot;
 157         u8 *tag = tag_buf;
 158         unsigned int i, j;
 159
 160         for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
 161                 tag[j] = (sdt->app_tag & 0xff00) >> 8;
 162                 tag[j+1] = sdt->app_tag & 0xff;
 163         }
 164 }
 165
 166 static struct blk_integrity dif_type1_integrity_crc = {
 167         .name                   = "T10-DIF-TYPE1-CRC",
 168         .generate_fn            = sd_dif_type1_generate_crc,
 169         .verify_fn              = sd_dif_type1_verify_crc,
 170         .get_tag_fn             = sd_dif_type1_get_tag,
 171         .set_tag_fn             = sd_dif_type1_set_tag,
 172         .tuple_size             = sizeof(struct sd_dif_tuple),
 173         .tag_size               = 0,
 174 };
 175
 176 static struct blk_integrity dif_type1_integrity_ip = {
 177         .name                   = "T10-DIF-TYPE1-IP",
 178         .generate_fn            = sd_dif_type1_generate_ip,
 179         .verify_fn              = sd_dif_type1_verify_ip,
 180         .get_tag_fn             = sd_dif_type1_get_tag,
 181         .set_tag_fn             = sd_dif_type1_set_tag,
 182         .tuple_size             = sizeof(struct sd_dif_tuple),
 183         .tag_size               = 0,
 184 };
 185
 186
 187 /*
 188  * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
 189  * tag space.
 190  */
 191 static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
 192 {
 193         void *buf = bix->data_buf;
 194         struct sd_dif_tuple *sdt = bix->prot_buf;
 195         unsigned int i;
 196
 197         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
 198                 sdt->guard_tag = fn(buf, bix->sector_size);
 199                 sdt->ref_tag = 0;
 200                 sdt->app_tag = 0;
 201
 202                 buf += bix->sector_size;
 203         }
 204 }
 205
 206 static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
 207 {
 208         sd_dif_type3_generate(bix, sd_dif_crc_fn);
 209 }
 210
 211 static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
 212 {
 213         sd_dif_type3_generate(bix, sd_dif_ip_fn);
 214 }
 215
 216 static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
 217 {
 218         void *buf = bix->data_buf;
 219         struct sd_dif_tuple *sdt = bix->prot_buf;
 220         sector_t sector = bix->sector;
 221         unsigned int i;
 222         __u16 csum;
 223
 224         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
 225                 /* Unwritten sectors */
 226                 if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
 227                         return 0;
 228
 229                 csum = fn(buf, bix->sector_size);
 230
 231                 if (sdt->guard_tag != csum) {
 232                         printk(KERN_ERR "%s: guard tag error on sector %lu " \
 233                                "(rcvd %04x, data %04x)\n", bix->disk_name,
 234                                (unsigned long)sector,
 235                                be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
 236                         return -EIO;
 237                 }
 238
 239                 buf += bix->sector_size;
 240                 sector++;
 241         }
 242
 243         return 0;
 244 }
 245
 246 static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
 247 {
 248         return sd_dif_type3_verify(bix, sd_dif_crc_fn);
 249 }
 250
 251 static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
 252 {
 253         return sd_dif_type3_verify(bix, sd_dif_ip_fn);
 254 }
 255
 256 static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
 257 {
 258         struct sd_dif_tuple *sdt = prot;
 259         u8 *tag = tag_buf;
 260         unsigned int i, j;
 261
 262         for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
 263                 sdt->app_tag = tag[j] << 8 | tag[j+1];
 264                 sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 |
 265                         tag[j+4] << 8 | tag[j+5];
 266         }
 267 }
 268
 269 static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
 270 {
 271         struct sd_dif_tuple *sdt = prot;
 272         u8 *tag = tag_buf;
 273         unsigned int i, j;
 274
 275         for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
 276                 tag[j] = (sdt->app_tag & 0xff00) >> 8;
 277                 tag[j+1] = sdt->app_tag & 0xff;
 278                 tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24;
 279                 tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16;
 280                 tag[j+4] = (sdt->ref_tag & 0xff00) >> 8;
 281                 tag[j+5] = sdt->ref_tag & 0xff;
 282                 BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff);
 283         }
 284 }
 285
 286 static struct blk_integrity dif_type3_integrity_crc = {
 287         .name                   = "T10-DIF-TYPE3-CRC",
 288         .generate_fn            = sd_dif_type3_generate_crc,
 289         .verify_fn              = sd_dif_type3_verify_crc,
 290         .get_tag_fn             = sd_dif_type3_get_tag,
 291         .set_tag_fn             = sd_dif_type3_set_tag,
 292         .tuple_size             = sizeof(struct sd_dif_tuple),
 293         .tag_size               = 0,
 294 };
 295
 296 static struct blk_integrity dif_type3_integrity_ip = {
 297         .name                   = "T10-DIF-TYPE3-IP",
 298         .generate_fn            = sd_dif_type3_generate_ip,
 299         .verify_fn              = sd_dif_type3_verify_ip,
 300         .get_tag_fn             = sd_dif_type3_get_tag,
 301         .set_tag_fn             = sd_dif_type3_set_tag,
 302         .tuple_size             = sizeof(struct sd_dif_tuple),
 303         .tag_size               = 0,
 304 };
 305
 306 /*
 307  * Configure exchange of protection information between OS and HBA.
 308  */
 309 void sd_dif_config_host(struct scsi_disk *sdkp)
 310 {
 311         struct scsi_device *sdp = sdkp->device;
 312         struct gendisk *disk = sdkp->disk;
 313         u8 type = sdkp->protection_type;
 314         int dif, dix;
 315
 316         dif = scsi_host_dif_capable(sdp->host, type);
 317         dix = scsi_host_dix_capable(sdp->host, type);
 318
 319         if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
 320                 dif = 0; dix = 1;
 321         }
 322
 323         if (!dix)
 324                 return;
 325
 326         /* Enable DMA of protection information */
 327         if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
 328                 if (type == SD_DIF_TYPE3_PROTECTION)
 329                         blk_integrity_register(disk, &dif_type3_integrity_ip);
 330                 else
 331                         blk_integrity_register(disk, &dif_type1_integrity_ip);
 332         else
 333                 if (type == SD_DIF_TYPE3_PROTECTION)
 334                         blk_integrity_register(disk, &dif_type3_integrity_crc);
 335                 else
 336                         blk_integrity_register(disk, &dif_type1_integrity_crc);
 337
 338         sd_printk(KERN_NOTICE, sdkp,
 339                   "Enabling DIX %s protection\n", disk->integrity->name);
 340
 341         /* Signal to block layer that we support sector tagging */
 342         if (dif && type && sdkp->ATO) {
 343                 if (type == SD_DIF_TYPE3_PROTECTION)
 344                         disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
 345                 else
 346                         disk->integrity->tag_size = sizeof(u16);
 347
 348                 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
 349                           disk->integrity->tag_size);
 350         }
 351 }
 352
 353 /*
 354  * The virtual start sector is the one that was originally submitted
 355  * by the block layer.  Due to partitioning, MD/DM cloning, etc. the
 356  * actual physical start sector is likely to be different.  Remap
 357  * protection information to match the physical LBA.
 358  *
 359  * From a protocol perspective there's a slight difference between
 360  * Type 1 and 2.  The latter uses 32-byte CDBs exclusively, and the
 361  * reference tag is seeded in the CDB.  This gives us the potential to
 362  * avoid virt->phys remapping during write.  However, at read time we
 363  * don't know whether the virt sector is the same as when we wrote it
 364  * (we could be reading from real disk as opposed to MD/DM device.  So
 365  * we always remap Type 2 making it identical to Type 1.
 366  *
 367  * Type 3 does not have a reference tag so no remapping is required.
 368  */
 369 void sd_dif_prepare(struct request *rq, sector_t hw_sector,
 370                     unsigned int sector_sz)
 371 {
 372         const int tuple_sz = sizeof(struct sd_dif_tuple);
 373         struct bio *bio;
 374         struct scsi_disk *sdkp;
 375         struct sd_dif_tuple *sdt;
 376         unsigned int i, j;
 377         u32 phys, virt;
 378
 379         sdkp = rq->bio->bi_bdev->bd_disk->private_data;
 380
 381         if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
 382                 return;
 383
 384         phys = hw_sector & 0xffffffff;
 385
 386         __rq_for_each_bio(bio, rq) {
 387                 struct bio_vec *iv;
 388
 389                 /* Already remapped? */
 390                 if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
 391                         break;
 392
 393                 virt = bio->bi_integrity->bip_sector & 0xffffffff;
 394
 395                 bip_for_each_vec(iv, bio->bi_integrity, i) {
 396                         sdt = kmap_atomic(iv->bv_page)
 397                                 + iv->bv_offset;
 398
 399                         for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
 400
 401                                 if (be32_to_cpu(sdt->ref_tag) == virt)
 402                                         sdt->ref_tag = cpu_to_be32(phys);
 403
 404                                 virt++;
 405                                 phys++;
 406                         }
 407
 408                         kunmap_atomic(sdt);
 409                 }
 410
 411                 bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY);
 412         }
 413 }
 414
 415 /*
 416  * Remap physical sector values in the reference tag to the virtual
 417  * values expected by the block layer.
 418  */
 419 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 420 {
 421         const int tuple_sz = sizeof(struct sd_dif_tuple);
 422         struct scsi_disk *sdkp;
 423         struct bio *bio;
 424         struct sd_dif_tuple *sdt;
 425         unsigned int i, j, sectors, sector_sz;
 426         u32 phys, virt;
 427
 428         sdkp = scsi_disk(scmd->request->rq_disk);
 429
 430         if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
 431                 return;
 432
 433         sector_sz = scmd->device->sector_size;
 434         sectors = good_bytes / sector_sz;
 435
 436         phys = blk_rq_pos(scmd->request) & 0xffffffff;
 437         if (sector_sz == 4096)
 438                 phys >>= 3;
 439
 440         __rq_for_each_bio(bio, scmd->request) {
 441                 struct bio_vec *iv;
 442
 443                 virt = bio->bi_integrity->bip_sector & 0xffffffff;
 444
 445                 bip_for_each_vec(iv, bio->bi_integrity, i) {
 446                         sdt = kmap_atomic(iv->bv_page)
 447                                 + iv->bv_offset;
 448
 449                         for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
 450
 451                                 if (sectors == 0) {
 452                                         kunmap_atomic(sdt);
 453                                         return;
 454                                 }
 455
 456                                 if (be32_to_cpu(sdt->ref_tag) == phys)
 457                                         sdt->ref_tag = cpu_to_be32(virt);
 458
 459                                 virt++;
 460                                 phys++;
 461                                 sectors--;
 462                         }
 463
 464                         kunmap_atomic(sdt);
 465                 }
 466         }
 467 }
 468