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                 if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
  97                         printk(KERN_ERR
  98                                "%s: ref tag error on sector %lu (rcvd %u)\n",
  99                                bix->disk_name, (unsigned long)sector,
 100                                be32_to_cpu(sdt->ref_tag));
 101                         return -EIO;
 102                 }
 103
 104                 csum = fn(buf, bix->sector_size);
 105
 106                 if (sdt->guard_tag != csum) {
 107                         printk(KERN_ERR "%s: guard tag error on sector %lu " \
 108                                "(rcvd %04x, data %04x)\n", bix->disk_name,
 109                                (unsigned long)sector,
 110                                be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
 111                         return -EIO;
 112                 }
 113
 114                 buf += bix->sector_size;
 115                 sector++;
 116         }
 117
 118         return 0;
 119 }
 120
 121 static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
 122 {
 123         return sd_dif_type1_verify(bix, sd_dif_crc_fn);
 124 }
 125
 126 static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
 127 {
 128         return sd_dif_type1_verify(bix, sd_dif_ip_fn);
 129 }
 130
 131 static struct blk_integrity dif_type1_integrity_crc = {
 132         .name                   = "T10-DIF-TYPE1-CRC",
 133         .generate_fn            = sd_dif_type1_generate_crc,
 134         .verify_fn              = sd_dif_type1_verify_crc,
 135         .tuple_size             = sizeof(struct sd_dif_tuple),
 136         .tag_size               = 0,
 137 };
 138
 139 static struct blk_integrity dif_type1_integrity_ip = {
 140         .name                   = "T10-DIF-TYPE1-IP",
 141         .generate_fn            = sd_dif_type1_generate_ip,
 142         .verify_fn              = sd_dif_type1_verify_ip,
 143         .tuple_size             = sizeof(struct sd_dif_tuple),
 144         .tag_size               = 0,
 145 };
 146
 147
 148 /*
 149  * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
 150  * tag space.
 151  */
 152 static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
 153 {
 154         void *buf = bix->data_buf;
 155         struct sd_dif_tuple *sdt = bix->prot_buf;
 156         unsigned int i;
 157
 158         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
 159                 sdt->guard_tag = fn(buf, bix->sector_size);
 160                 sdt->ref_tag = 0;
 161                 sdt->app_tag = 0;
 162
 163                 buf += bix->sector_size;
 164         }
 165 }
 166
 167 static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
 168 {
 169         sd_dif_type3_generate(bix, sd_dif_crc_fn);
 170 }
 171
 172 static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
 173 {
 174         sd_dif_type3_generate(bix, sd_dif_ip_fn);
 175 }
 176
 177 static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
 178 {
 179         void *buf = bix->data_buf;
 180         struct sd_dif_tuple *sdt = bix->prot_buf;
 181         sector_t sector = bix->sector;
 182         unsigned int i;
 183         __u16 csum;
 184
 185         for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
 186                 /* Unwritten sectors */
 187                 if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
 188                         return 0;
 189
 190                 csum = fn(buf, bix->sector_size);
 191
 192                 if (sdt->guard_tag != csum) {
 193                         printk(KERN_ERR "%s: guard tag error on sector %lu " \
 194                                "(rcvd %04x, data %04x)\n", bix->disk_name,
 195                                (unsigned long)sector,
 196                                be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
 197                         return -EIO;
 198                 }
 199
 200                 buf += bix->sector_size;
 201                 sector++;
 202         }
 203
 204         return 0;
 205 }
 206
 207 static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
 208 {
 209         return sd_dif_type3_verify(bix, sd_dif_crc_fn);
 210 }
 211
 212 static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
 213 {
 214         return sd_dif_type3_verify(bix, sd_dif_ip_fn);
 215 }
 216
 217 static struct blk_integrity dif_type3_integrity_crc = {
 218         .name                   = "T10-DIF-TYPE3-CRC",
 219         .generate_fn            = sd_dif_type3_generate_crc,
 220         .verify_fn              = sd_dif_type3_verify_crc,
 221         .tuple_size             = sizeof(struct sd_dif_tuple),
 222         .tag_size               = 0,
 223 };
 224
 225 static struct blk_integrity dif_type3_integrity_ip = {
 226         .name                   = "T10-DIF-TYPE3-IP",
 227         .generate_fn            = sd_dif_type3_generate_ip,
 228         .verify_fn              = sd_dif_type3_verify_ip,
 229         .tuple_size             = sizeof(struct sd_dif_tuple),
 230         .tag_size               = 0,
 231 };
 232
 233 /*
 234  * Configure exchange of protection information between OS and HBA.
 235  */
 236 void sd_dif_config_host(struct scsi_disk *sdkp)
 237 {
 238         struct scsi_device *sdp = sdkp->device;
 239         struct gendisk *disk = sdkp->disk;
 240         u8 type = sdkp->protection_type;
 241         int dif, dix;
 242
 243         dif = scsi_host_dif_capable(sdp->host, type);
 244         dix = scsi_host_dix_capable(sdp->host, type);
 245
 246         if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
 247                 dif = 0; dix = 1;
 248         }
 249
 250         if (!dix)
 251                 return;
 252
 253         /* Enable DMA of protection information */
 254         if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP)
 255                 if (type == SD_DIF_TYPE3_PROTECTION)
 256                         blk_integrity_register(disk, &dif_type3_integrity_ip);
 257                 else
 258                         blk_integrity_register(disk, &dif_type1_integrity_ip);
 259         else
 260                 if (type == SD_DIF_TYPE3_PROTECTION)
 261                         blk_integrity_register(disk, &dif_type3_integrity_crc);
 262                 else
 263                         blk_integrity_register(disk, &dif_type1_integrity_crc);
 264
 265         sd_printk(KERN_NOTICE, sdkp,
 266                   "Enabling DIX %s protection\n", disk->integrity->name);
 267
 268         /* Signal to block layer that we support sector tagging */
 269         if (dif && type && sdkp->ATO) {
 270                 if (type == SD_DIF_TYPE3_PROTECTION)
 271                         disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
 272                 else
 273                         disk->integrity->tag_size = sizeof(u16);
 274
 275                 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
 276                           disk->integrity->tag_size);
 277         }
 278 }
 279
 280 /*
 281  * The virtual start sector is the one that was originally submitted
 282  * by the block layer.  Due to partitioning, MD/DM cloning, etc. the
 283  * actual physical start sector is likely to be different.  Remap
 284  * protection information to match the physical LBA.
 285  *
 286  * From a protocol perspective there's a slight difference between
 287  * Type 1 and 2.  The latter uses 32-byte CDBs exclusively, and the
 288  * reference tag is seeded in the CDB.  This gives us the potential to
 289  * avoid virt->phys remapping during write.  However, at read time we
 290  * don't know whether the virt sector is the same as when we wrote it
 291  * (we could be reading from real disk as opposed to MD/DM device.  So
 292  * we always remap Type 2 making it identical to Type 1.
 293  *
 294  * Type 3 does not have a reference tag so no remapping is required.
 295  */
 296 void sd_dif_prepare(struct request *rq, sector_t hw_sector,
 297                     unsigned int sector_sz)
 298 {
 299         const int tuple_sz = sizeof(struct sd_dif_tuple);
 300         struct bio *bio;
 301         struct scsi_disk *sdkp;
 302         struct sd_dif_tuple *sdt;
 303         u32 phys, virt;
 304
 305         sdkp = rq->bio->bi_bdev->bd_disk->private_data;
 306
 307         if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
 308                 return;
 309
 310         phys = hw_sector & 0xffffffff;
 311
 312         __rq_for_each_bio(bio, rq) {
 313                 struct bio_vec iv;
 314                 struct bvec_iter iter;
 315                 unsigned int j;
 316
 317                 /* Already remapped? */
 318                 if (bio_flagged(bio, BIO_MAPPED_INTEGRITY))
 319                         break;
 320
 321                 virt = bio_integrity(bio)->bip_iter.bi_sector & 0xffffffff;
 322
 323                 bip_for_each_vec(iv, bio_integrity(bio), iter) {
 324                         sdt = kmap_atomic(iv.bv_page)
 325                                 + iv.bv_offset;
 326
 327                         for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) {
 328
 329                                 if (be32_to_cpu(sdt->ref_tag) == virt)
 330                                         sdt->ref_tag = cpu_to_be32(phys);
 331
 332                                 virt++;
 333                                 phys++;
 334                         }
 335
 336                         kunmap_atomic(sdt);
 337                 }
 338
 339                 bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY);
 340         }
 341 }
 342
 343 /*
 344  * Remap physical sector values in the reference tag to the virtual
 345  * values expected by the block layer.
 346  */
 347 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
 348 {
 349         const int tuple_sz = sizeof(struct sd_dif_tuple);
 350         struct scsi_disk *sdkp;
 351         struct bio *bio;
 352         struct sd_dif_tuple *sdt;
 353         unsigned int j, sectors, sector_sz;
 354         u32 phys, virt;
 355
 356         sdkp = scsi_disk(scmd->request->rq_disk);
 357
 358         if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
 359                 return;
 360
 361         sector_sz = scmd->device->sector_size;
 362         sectors = good_bytes / sector_sz;
 363
 364         phys = blk_rq_pos(scmd->request) & 0xffffffff;
 365         if (sector_sz == 4096)
 366                 phys >>= 3;
 367
 368         __rq_for_each_bio(bio, scmd->request) {
 369                 struct bio_vec iv;
 370                 struct bvec_iter iter;
 371
 372                 virt = bio_integrity(bio)->bip_iter.bi_sector & 0xffffffff;
 373
 374                 bip_for_each_vec(iv, bio_integrity(bio), iter) {
 375                         sdt = kmap_atomic(iv.bv_page)
 376                                 + iv.bv_offset;
 377
 378                         for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) {
 379
 380                                 if (sectors == 0) {
 381                                         kunmap_atomic(sdt);
 382                                         return;
 383                                 }
 384
 385                                 if (be32_to_cpu(sdt->ref_tag) == phys)
 386                                         sdt->ref_tag = cpu_to_be32(virt);
 387
 388                                 virt++;
 389                                 phys++;
 390                                 sectors--;
 391                         }
 392
 393                         kunmap_atomic(sdt);
 394                 }
 395         }
 396 }
 397