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 /* 132 * Functions for interleaving and deinterleaving application tags 133 */ 134 static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors) 135 { 136 struct sd_dif_tuple *sdt = prot; 137 u8 *tag = tag_buf; 138 unsigned int i, j; 139 140 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) { 141 sdt->app_tag = tag[j] << 8 | tag[j+1]; 142 BUG_ON(sdt->app_tag == 0xffff); 143 } 144 } 145 146 static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors) 147 { 148 struct sd_dif_tuple *sdt = prot; 149 u8 *tag = tag_buf; 150 unsigned int i, j; 151 152 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) { 153 tag[j] = (sdt->app_tag & 0xff00) >> 8; 154 tag[j+1] = sdt->app_tag & 0xff; 155 } 156 } 157 158 static struct blk_integrity dif_type1_integrity_crc = { 159 .name = "T10-DIF-TYPE1-CRC", 160 .generate_fn = sd_dif_type1_generate_crc, 161 .verify_fn = sd_dif_type1_verify_crc, 162 .get_tag_fn = sd_dif_type1_get_tag, 163 .set_tag_fn = sd_dif_type1_set_tag, 164 .tuple_size = sizeof(struct sd_dif_tuple), 165 .tag_size = 0, 166 }; 167 168 static struct blk_integrity dif_type1_integrity_ip = { 169 .name = "T10-DIF-TYPE1-IP", 170 .generate_fn = sd_dif_type1_generate_ip, 171 .verify_fn = sd_dif_type1_verify_ip, 172 .get_tag_fn = sd_dif_type1_get_tag, 173 .set_tag_fn = sd_dif_type1_set_tag, 174 .tuple_size = sizeof(struct sd_dif_tuple), 175 .tag_size = 0, 176 }; 177 178 179 /* 180 * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque 181 * tag space. 182 */ 183 static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn) 184 { 185 void *buf = bix->data_buf; 186 struct sd_dif_tuple *sdt = bix->prot_buf; 187 unsigned int i; 188 189 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 190 sdt->guard_tag = fn(buf, bix->sector_size); 191 sdt->ref_tag = 0; 192 sdt->app_tag = 0; 193 194 buf += bix->sector_size; 195 } 196 } 197 198 static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix) 199 { 200 sd_dif_type3_generate(bix, sd_dif_crc_fn); 201 } 202 203 static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix) 204 { 205 sd_dif_type3_generate(bix, sd_dif_ip_fn); 206 } 207 208 static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn) 209 { 210 void *buf = bix->data_buf; 211 struct sd_dif_tuple *sdt = bix->prot_buf; 212 sector_t sector = bix->sector; 213 unsigned int i; 214 __u16 csum; 215 216 for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) { 217 /* Unwritten sectors */ 218 if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff) 219 return 0; 220 221 csum = fn(buf, bix->sector_size); 222 223 if (sdt->guard_tag != csum) { 224 printk(KERN_ERR "%s: guard tag error on sector %lu " \ 225 "(rcvd %04x, data %04x)\n", bix->disk_name, 226 (unsigned long)sector, 227 be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum)); 228 return -EIO; 229 } 230 231 buf += bix->sector_size; 232 sector++; 233 } 234 235 return 0; 236 } 237 238 static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix) 239 { 240 return sd_dif_type3_verify(bix, sd_dif_crc_fn); 241 } 242 243 static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix) 244 { 245 return sd_dif_type3_verify(bix, sd_dif_ip_fn); 246 } 247 248 static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors) 249 { 250 struct sd_dif_tuple *sdt = prot; 251 u8 *tag = tag_buf; 252 unsigned int i, j; 253 254 for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) { 255 sdt->app_tag = tag[j] << 8 | tag[j+1]; 256 sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 | 257 tag[j+4] << 8 | tag[j+5]; 258 } 259 } 260 261 static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors) 262 { 263 struct sd_dif_tuple *sdt = prot; 264 u8 *tag = tag_buf; 265 unsigned int i, j; 266 267 for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) { 268 tag[j] = (sdt->app_tag & 0xff00) >> 8; 269 tag[j+1] = sdt->app_tag & 0xff; 270 tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24; 271 tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16; 272 tag[j+4] = (sdt->ref_tag & 0xff00) >> 8; 273 tag[j+5] = sdt->ref_tag & 0xff; 274 BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff); 275 } 276 } 277 278 static struct blk_integrity dif_type3_integrity_crc = { 279 .name = "T10-DIF-TYPE3-CRC", 280 .generate_fn = sd_dif_type3_generate_crc, 281 .verify_fn = sd_dif_type3_verify_crc, 282 .get_tag_fn = sd_dif_type3_get_tag, 283 .set_tag_fn = sd_dif_type3_set_tag, 284 .tuple_size = sizeof(struct sd_dif_tuple), 285 .tag_size = 0, 286 }; 287 288 static struct blk_integrity dif_type3_integrity_ip = { 289 .name = "T10-DIF-TYPE3-IP", 290 .generate_fn = sd_dif_type3_generate_ip, 291 .verify_fn = sd_dif_type3_verify_ip, 292 .get_tag_fn = sd_dif_type3_get_tag, 293 .set_tag_fn = sd_dif_type3_set_tag, 294 .tuple_size = sizeof(struct sd_dif_tuple), 295 .tag_size = 0, 296 }; 297 298 /* 299 * Configure exchange of protection information between OS and HBA. 300 */ 301 void sd_dif_config_host(struct scsi_disk *sdkp) 302 { 303 struct scsi_device *sdp = sdkp->device; 304 struct gendisk *disk = sdkp->disk; 305 u8 type = sdkp->protection_type; 306 int dif, dix; 307 308 dif = scsi_host_dif_capable(sdp->host, type); 309 dix = scsi_host_dix_capable(sdp->host, type); 310 311 if (!dix && scsi_host_dix_capable(sdp->host, 0)) { 312 dif = 0; dix = 1; 313 } 314 315 if (!dix) 316 return; 317 318 /* Enable DMA of protection information */ 319 if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) 320 if (type == SD_DIF_TYPE3_PROTECTION) 321 blk_integrity_register(disk, &dif_type3_integrity_ip); 322 else 323 blk_integrity_register(disk, &dif_type1_integrity_ip); 324 else 325 if (type == SD_DIF_TYPE3_PROTECTION) 326 blk_integrity_register(disk, &dif_type3_integrity_crc); 327 else 328 blk_integrity_register(disk, &dif_type1_integrity_crc); 329 330 sd_printk(KERN_NOTICE, sdkp, 331 "Enabling DIX %s protection\n", disk->integrity->name); 332 333 /* Signal to block layer that we support sector tagging */ 334 if (dif && type && sdkp->ATO) { 335 if (type == SD_DIF_TYPE3_PROTECTION) 336 disk->integrity->tag_size = sizeof(u16) + sizeof(u32); 337 else 338 disk->integrity->tag_size = sizeof(u16); 339 340 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n", 341 disk->integrity->tag_size); 342 } 343 } 344 345 /* 346 * The virtual start sector is the one that was originally submitted 347 * by the block layer. Due to partitioning, MD/DM cloning, etc. the 348 * actual physical start sector is likely to be different. Remap 349 * protection information to match the physical LBA. 350 * 351 * From a protocol perspective there's a slight difference between 352 * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the 353 * reference tag is seeded in the CDB. This gives us the potential to 354 * avoid virt->phys remapping during write. However, at read time we 355 * don't know whether the virt sector is the same as when we wrote it 356 * (we could be reading from real disk as opposed to MD/DM device. So 357 * we always remap Type 2 making it identical to Type 1. 358 * 359 * Type 3 does not have a reference tag so no remapping is required. 360 */ 361 void sd_dif_prepare(struct request *rq, sector_t hw_sector, 362 unsigned int sector_sz) 363 { 364 const int tuple_sz = sizeof(struct sd_dif_tuple); 365 struct bio *bio; 366 struct scsi_disk *sdkp; 367 struct sd_dif_tuple *sdt; 368 u32 phys, virt; 369 370 sdkp = rq->bio->bi_bdev->bd_disk->private_data; 371 372 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION) 373 return; 374 375 phys = hw_sector & 0xffffffff; 376 377 __rq_for_each_bio(bio, rq) { 378 struct bio_vec iv; 379 struct bvec_iter iter; 380 unsigned int j; 381 382 /* Already remapped? */ 383 if (bio_flagged(bio, BIO_MAPPED_INTEGRITY)) 384 break; 385 386 virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff; 387 388 bip_for_each_vec(iv, bio->bi_integrity, iter) { 389 sdt = kmap_atomic(iv.bv_page) 390 + iv.bv_offset; 391 392 for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) { 393 394 if (be32_to_cpu(sdt->ref_tag) == virt) 395 sdt->ref_tag = cpu_to_be32(phys); 396 397 virt++; 398 phys++; 399 } 400 401 kunmap_atomic(sdt); 402 } 403 404 bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY); 405 } 406 } 407 408 /* 409 * Remap physical sector values in the reference tag to the virtual 410 * values expected by the block layer. 411 */ 412 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes) 413 { 414 const int tuple_sz = sizeof(struct sd_dif_tuple); 415 struct scsi_disk *sdkp; 416 struct bio *bio; 417 struct sd_dif_tuple *sdt; 418 unsigned int j, sectors, sector_sz; 419 u32 phys, virt; 420 421 sdkp = scsi_disk(scmd->request->rq_disk); 422 423 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0) 424 return; 425 426 sector_sz = scmd->device->sector_size; 427 sectors = good_bytes / sector_sz; 428 429 phys = blk_rq_pos(scmd->request) & 0xffffffff; 430 if (sector_sz == 4096) 431 phys >>= 3; 432 433 __rq_for_each_bio(bio, scmd->request) { 434 struct bio_vec iv; 435 struct bvec_iter iter; 436 437 virt = bio->bi_integrity->bip_iter.bi_sector & 0xffffffff; 438 439 bip_for_each_vec(iv, bio->bi_integrity, iter) { 440 sdt = kmap_atomic(iv.bv_page) 441 + iv.bv_offset; 442 443 for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) { 444 445 if (sectors == 0) { 446 kunmap_atomic(sdt); 447 return; 448 } 449 450 if (be32_to_cpu(sdt->ref_tag) == phys) 451 sdt->ref_tag = cpu_to_be32(virt); 452 453 virt++; 454 phys++; 455 sectors--; 456 } 457 458 kunmap_atomic(sdt); 459 } 460 } 461 } 462 463