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_iter *iter, csum_fn *fn) 57 { 58 void *buf = iter->data_buf; 59 struct sd_dif_tuple *sdt = iter->prot_buf; 60 sector_t seed = iter->seed; 61 unsigned int i; 62 63 for (i = 0 ; i < iter->data_size ; i += iter->interval, sdt++) { 64 sdt->guard_tag = fn(buf, iter->interval); 65 sdt->ref_tag = cpu_to_be32(seed & 0xffffffff); 66 sdt->app_tag = 0; 67 68 buf += iter->interval; 69 seed++; 70 } 71 } 72 73 static int sd_dif_type1_generate_crc(struct blk_integrity_iter *iter) 74 { 75 sd_dif_type1_generate(iter, sd_dif_crc_fn); 76 return 0; 77 } 78 79 static int sd_dif_type1_generate_ip(struct blk_integrity_iter *iter) 80 { 81 sd_dif_type1_generate(iter, sd_dif_ip_fn); 82 return 0; 83 } 84 85 static int sd_dif_type1_verify(struct blk_integrity_iter *iter, csum_fn *fn) 86 { 87 void *buf = iter->data_buf; 88 struct sd_dif_tuple *sdt = iter->prot_buf; 89 sector_t seed = iter->seed; 90 unsigned int i; 91 __u16 csum; 92 93 for (i = 0 ; i < iter->data_size ; i += iter->interval, sdt++) { 94 /* Unwritten sectors */ 95 if (sdt->app_tag == 0xffff) 96 return 0; 97 98 if (be32_to_cpu(sdt->ref_tag) != (seed & 0xffffffff)) { 99 printk(KERN_ERR 100 "%s: ref tag error on sector %lu (rcvd %u)\n", 101 iter->disk_name, (unsigned long)seed, 102 be32_to_cpu(sdt->ref_tag)); 103 return -EIO; 104 } 105 106 csum = fn(buf, iter->interval); 107 108 if (sdt->guard_tag != csum) { 109 printk(KERN_ERR "%s: guard tag error on sector %lu " \ 110 "(rcvd %04x, data %04x)\n", iter->disk_name, 111 (unsigned long)seed, 112 be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum)); 113 return -EIO; 114 } 115 116 buf += iter->interval; 117 seed++; 118 } 119 120 return 0; 121 } 122 123 static int sd_dif_type1_verify_crc(struct blk_integrity_iter *iter) 124 { 125 return sd_dif_type1_verify(iter, sd_dif_crc_fn); 126 } 127 128 static int sd_dif_type1_verify_ip(struct blk_integrity_iter *iter) 129 { 130 return sd_dif_type1_verify(iter, sd_dif_ip_fn); 131 } 132 133 static struct blk_integrity dif_type1_integrity_crc = { 134 .name = "T10-DIF-TYPE1-CRC", 135 .generate_fn = sd_dif_type1_generate_crc, 136 .verify_fn = sd_dif_type1_verify_crc, 137 .tuple_size = sizeof(struct sd_dif_tuple), 138 .tag_size = 0, 139 }; 140 141 static struct blk_integrity dif_type1_integrity_ip = { 142 .name = "T10-DIF-TYPE1-IP", 143 .generate_fn = sd_dif_type1_generate_ip, 144 .verify_fn = sd_dif_type1_verify_ip, 145 .tuple_size = sizeof(struct sd_dif_tuple), 146 .tag_size = 0, 147 }; 148 149 150 /* 151 * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque 152 * tag space. 153 */ 154 static void sd_dif_type3_generate(struct blk_integrity_iter *iter, csum_fn *fn) 155 { 156 void *buf = iter->data_buf; 157 struct sd_dif_tuple *sdt = iter->prot_buf; 158 unsigned int i; 159 160 for (i = 0 ; i < iter->data_size ; i += iter->interval, sdt++) { 161 sdt->guard_tag = fn(buf, iter->interval); 162 sdt->ref_tag = 0; 163 sdt->app_tag = 0; 164 165 buf += iter->interval; 166 } 167 } 168 169 static int sd_dif_type3_generate_crc(struct blk_integrity_iter *iter) 170 { 171 sd_dif_type3_generate(iter, sd_dif_crc_fn); 172 return 0; 173 } 174 175 static int sd_dif_type3_generate_ip(struct blk_integrity_iter *iter) 176 { 177 sd_dif_type3_generate(iter, sd_dif_ip_fn); 178 return 0; 179 } 180 181 static int sd_dif_type3_verify(struct blk_integrity_iter *iter, csum_fn *fn) 182 { 183 void *buf = iter->data_buf; 184 struct sd_dif_tuple *sdt = iter->prot_buf; 185 sector_t seed = iter->seed; 186 unsigned int i; 187 __u16 csum; 188 189 for (i = 0 ; i < iter->data_size ; i += iter->interval, sdt++) { 190 /* Unwritten sectors */ 191 if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff) 192 return 0; 193 194 csum = fn(buf, iter->interval); 195 196 if (sdt->guard_tag != csum) { 197 printk(KERN_ERR "%s: guard tag error on sector %lu " \ 198 "(rcvd %04x, data %04x)\n", iter->disk_name, 199 (unsigned long)seed, 200 be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum)); 201 return -EIO; 202 } 203 204 buf += iter->interval; 205 seed++; 206 } 207 208 return 0; 209 } 210 211 static int sd_dif_type3_verify_crc(struct blk_integrity_iter *iter) 212 { 213 return sd_dif_type3_verify(iter, sd_dif_crc_fn); 214 } 215 216 static int sd_dif_type3_verify_ip(struct blk_integrity_iter *iter) 217 { 218 return sd_dif_type3_verify(iter, sd_dif_ip_fn); 219 } 220 221 static struct blk_integrity dif_type3_integrity_crc = { 222 .name = "T10-DIF-TYPE3-CRC", 223 .generate_fn = sd_dif_type3_generate_crc, 224 .verify_fn = sd_dif_type3_verify_crc, 225 .tuple_size = sizeof(struct sd_dif_tuple), 226 .tag_size = 0, 227 }; 228 229 static struct blk_integrity dif_type3_integrity_ip = { 230 .name = "T10-DIF-TYPE3-IP", 231 .generate_fn = sd_dif_type3_generate_ip, 232 .verify_fn = sd_dif_type3_verify_ip, 233 .tuple_size = sizeof(struct sd_dif_tuple), 234 .tag_size = 0, 235 }; 236 237 /* 238 * Configure exchange of protection information between OS and HBA. 239 */ 240 void sd_dif_config_host(struct scsi_disk *sdkp) 241 { 242 struct scsi_device *sdp = sdkp->device; 243 struct gendisk *disk = sdkp->disk; 244 u8 type = sdkp->protection_type; 245 int dif, dix; 246 247 dif = scsi_host_dif_capable(sdp->host, type); 248 dix = scsi_host_dix_capable(sdp->host, type); 249 250 if (!dix && scsi_host_dix_capable(sdp->host, 0)) { 251 dif = 0; dix = 1; 252 } 253 254 if (!dix) 255 return; 256 257 /* Enable DMA of protection information */ 258 if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) 259 if (type == SD_DIF_TYPE3_PROTECTION) 260 blk_integrity_register(disk, &dif_type3_integrity_ip); 261 else 262 blk_integrity_register(disk, &dif_type1_integrity_ip); 263 else 264 if (type == SD_DIF_TYPE3_PROTECTION) 265 blk_integrity_register(disk, &dif_type3_integrity_crc); 266 else 267 blk_integrity_register(disk, &dif_type1_integrity_crc); 268 269 sd_printk(KERN_NOTICE, sdkp, 270 "Enabling DIX %s protection\n", disk->integrity->name); 271 272 /* Signal to block layer that we support sector tagging */ 273 if (dif && type) { 274 275 disk->integrity->flags |= BLK_INTEGRITY_DEVICE_CAPABLE; 276 277 if (!sdkp) 278 return; 279 280 if (type == SD_DIF_TYPE3_PROTECTION) 281 disk->integrity->tag_size = sizeof(u16) + sizeof(u32); 282 else 283 disk->integrity->tag_size = sizeof(u16); 284 285 sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n", 286 disk->integrity->tag_size); 287 } 288 } 289 290 /* 291 * The virtual start sector is the one that was originally submitted 292 * by the block layer. Due to partitioning, MD/DM cloning, etc. the 293 * actual physical start sector is likely to be different. Remap 294 * protection information to match the physical LBA. 295 * 296 * From a protocol perspective there's a slight difference between 297 * Type 1 and 2. The latter uses 32-byte CDBs exclusively, and the 298 * reference tag is seeded in the CDB. This gives us the potential to 299 * avoid virt->phys remapping during write. However, at read time we 300 * don't know whether the virt sector is the same as when we wrote it 301 * (we could be reading from real disk as opposed to MD/DM device. So 302 * we always remap Type 2 making it identical to Type 1. 303 * 304 * Type 3 does not have a reference tag so no remapping is required. 305 */ 306 void sd_dif_prepare(struct request *rq, sector_t hw_sector, 307 unsigned int sector_sz) 308 { 309 const int tuple_sz = sizeof(struct sd_dif_tuple); 310 struct bio *bio; 311 struct scsi_disk *sdkp; 312 struct sd_dif_tuple *sdt; 313 u32 phys, virt; 314 315 sdkp = rq->bio->bi_bdev->bd_disk->private_data; 316 317 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION) 318 return; 319 320 phys = hw_sector & 0xffffffff; 321 322 __rq_for_each_bio(bio, rq) { 323 struct bio_integrity_payload *bip = bio_integrity(bio); 324 struct bio_vec iv; 325 struct bvec_iter iter; 326 unsigned int j; 327 328 /* Already remapped? */ 329 if (bio_flagged(bio, BIO_MAPPED_INTEGRITY)) 330 break; 331 332 virt = bip_get_seed(bip) & 0xffffffff; 333 334 bip_for_each_vec(iv, bip, iter) { 335 sdt = kmap_atomic(iv.bv_page) 336 + iv.bv_offset; 337 338 for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) { 339 340 if (be32_to_cpu(sdt->ref_tag) == virt) 341 sdt->ref_tag = cpu_to_be32(phys); 342 343 virt++; 344 phys++; 345 } 346 347 kunmap_atomic(sdt); 348 } 349 350 bio->bi_flags |= (1 << BIO_MAPPED_INTEGRITY); 351 } 352 } 353 354 /* 355 * Remap physical sector values in the reference tag to the virtual 356 * values expected by the block layer. 357 */ 358 void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes) 359 { 360 const int tuple_sz = sizeof(struct sd_dif_tuple); 361 struct scsi_disk *sdkp; 362 struct bio *bio; 363 struct sd_dif_tuple *sdt; 364 unsigned int j, sectors, sector_sz; 365 u32 phys, virt; 366 367 sdkp = scsi_disk(scmd->request->rq_disk); 368 369 if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0) 370 return; 371 372 sector_sz = scmd->device->sector_size; 373 sectors = good_bytes / sector_sz; 374 375 phys = blk_rq_pos(scmd->request) & 0xffffffff; 376 if (sector_sz == 4096) 377 phys >>= 3; 378 379 __rq_for_each_bio(bio, scmd->request) { 380 struct bio_integrity_payload *bip = bio_integrity(bio); 381 struct bio_vec iv; 382 struct bvec_iter iter; 383 384 virt = bip_get_seed(bip) & 0xffffffff; 385 386 bip_for_each_vec(iv, bip, iter) { 387 sdt = kmap_atomic(iv.bv_page) 388 + iv.bv_offset; 389 390 for (j = 0; j < iv.bv_len; j += tuple_sz, sdt++) { 391 392 if (sectors == 0) { 393 kunmap_atomic(sdt); 394 return; 395 } 396 397 if (be32_to_cpu(sdt->ref_tag) == phys) 398 sdt->ref_tag = cpu_to_be32(virt); 399 400 virt++; 401 phys++; 402 sectors--; 403 } 404 405 kunmap_atomic(sdt); 406 } 407 } 408 } 409 410