block/t10-pi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * t10_pi.c - Functions for generating and verifying T10 Protection
   4  *            Information.
   5  */
   6
   7 #include <linux/t10-pi.h>
   8 #include <linux/blkdev.h>
   9 #include <linux/crc-t10dif.h>
  10 #include <net/checksum.h>
  11
  12 typedef __be16 (csum_fn) (void *, unsigned int);
  13
  14 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
  15 {
  16         return cpu_to_be16(crc_t10dif(data, len));
  17 }
  18
  19 static __be16 t10_pi_ip_fn(void *data, unsigned int len)
  20 {
  21         return (__force __be16)ip_compute_csum(data, len);
  22 }
  23
  24 /*
  25  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
  26  * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
  27  * tag.
  28  */
  29 static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
  30                 csum_fn *fn, enum t10_dif_type type)
  31 {
  32         unsigned int i;
  33
  34         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  35                 struct t10_pi_tuple *pi = iter->prot_buf;
  36
  37                 pi->guard_tag = fn(iter->data_buf, iter->interval);
  38                 pi->app_tag = 0;
  39
  40                 if (type == T10_PI_TYPE1_PROTECTION)
  41                         pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
  42                 else
  43                         pi->ref_tag = 0;
  44
  45                 iter->data_buf += iter->interval;
  46                 iter->prot_buf += sizeof(struct t10_pi_tuple);
  47                 iter->seed++;
  48         }
  49
  50         return BLK_STS_OK;
  51 }
  52
  53 static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
  54                 csum_fn *fn, enum t10_dif_type type)
  55 {
  56         unsigned int i;
  57
  58         BUG_ON(type == T10_PI_TYPE0_PROTECTION);
  59
  60         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  61                 struct t10_pi_tuple *pi = iter->prot_buf;
  62                 __be16 csum;
  63
  64                 if (type == T10_PI_TYPE1_PROTECTION ||
  65                     type == T10_PI_TYPE2_PROTECTION) {
  66                         if (pi->app_tag == T10_PI_APP_ESCAPE)
  67                                 goto next;
  68
  69                         if (be32_to_cpu(pi->ref_tag) !=
  70                             lower_32_bits(iter->seed)) {
  71                                 pr_err("%s: ref tag error at location %llu " \
  72                                        "(rcvd %u)\n", iter->disk_name,
  73                                        (unsigned long long)
  74                                        iter->seed, be32_to_cpu(pi->ref_tag));
  75                                 return BLK_STS_PROTECTION;
  76                         }
  77                 } else if (type == T10_PI_TYPE3_PROTECTION) {
  78                         if (pi->app_tag == T10_PI_APP_ESCAPE &&
  79                             pi->ref_tag == T10_PI_REF_ESCAPE)
  80                                 goto next;
  81                 }
  82
  83                 csum = fn(iter->data_buf, iter->interval);
  84
  85                 if (pi->guard_tag != csum) {
  86                         pr_err("%s: guard tag error at sector %llu " \
  87                                "(rcvd %04x, want %04x)\n", iter->disk_name,
  88                                (unsigned long long)iter->seed,
  89                                be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
  90                         return BLK_STS_PROTECTION;
  91                 }
  92
  93 next:
  94                 iter->data_buf += iter->interval;
  95                 iter->prot_buf += sizeof(struct t10_pi_tuple);
  96                 iter->seed++;
  97         }
  98
  99         return BLK_STS_OK;
 100 }
 101
 102 static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
 103 {
 104         return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
 105 }
 106
 107 static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
 108 {
 109         return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
 110 }
 111
 112 static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
 113 {
 114         return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
 115 }
 116
 117 static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
 118 {
 119         return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
 120 }
 121
 122 /**
 123  * t10_pi_type1_prepare - prepare PI prior submitting request to device
 124  * @rq:              request with PI that should be prepared
 125  *
 126  * For Type 1/Type 2, the virtual start sector is the one that was
 127  * originally submitted by the block layer for the ref_tag usage. Due to
 128  * partitioning, MD/DM cloning, etc. the actual physical start sector is
 129  * likely to be different. Remap protection information to match the
 130  * physical LBA.
 131  */
 132 static void t10_pi_type1_prepare(struct request *rq)
 133 {
 134         const int tuple_sz = rq->q->integrity.tuple_size;
 135         u32 ref_tag = t10_pi_ref_tag(rq);
 136         struct bio *bio;
 137
 138         __rq_for_each_bio(bio, rq) {
 139                 struct bio_integrity_payload *bip = bio_integrity(bio);
 140                 u32 virt = bip_get_seed(bip) & 0xffffffff;
 141                 struct bio_vec iv;
 142                 struct bvec_iter iter;
 143
 144                 /* Already remapped? */
 145                 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
 146                         break;
 147
 148                 bip_for_each_vec(iv, bip, iter) {
 149                         void *p, *pmap;
 150                         unsigned int j;
 151
 152                         pmap = kmap_atomic(iv.bv_page);
 153                         p = pmap + iv.bv_offset;
 154                         for (j = 0; j < iv.bv_len; j += tuple_sz) {
 155                                 struct t10_pi_tuple *pi = p;
 156
 157                                 if (be32_to_cpu(pi->ref_tag) == virt)
 158                                         pi->ref_tag = cpu_to_be32(ref_tag);
 159                                 virt++;
 160                                 ref_tag++;
 161                                 p += tuple_sz;
 162                         }
 163
 164                         kunmap_atomic(pmap);
 165                 }
 166
 167                 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 168         }
 169 }
 170
 171 /**
 172  * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
 173  * @rq:              request with PI that should be prepared
 174  * @nr_bytes:        total bytes to prepare
 175  *
 176  * For Type 1/Type 2, the virtual start sector is the one that was
 177  * originally submitted by the block layer for the ref_tag usage. Due to
 178  * partitioning, MD/DM cloning, etc. the actual physical start sector is
 179  * likely to be different. Since the physical start sector was submitted
 180  * to the device, we should remap it back to virtual values expected by the
 181  * block layer.
 182  */
 183 static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
 184 {
 185         unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
 186         const int tuple_sz = rq->q->integrity.tuple_size;
 187         u32 ref_tag = t10_pi_ref_tag(rq);
 188         struct bio *bio;
 189
 190         __rq_for_each_bio(bio, rq) {
 191                 struct bio_integrity_payload *bip = bio_integrity(bio);
 192                 u32 virt = bip_get_seed(bip) & 0xffffffff;
 193                 struct bio_vec iv;
 194                 struct bvec_iter iter;
 195
 196                 bip_for_each_vec(iv, bip, iter) {
 197                         void *p, *pmap;
 198                         unsigned int j;
 199
 200                         pmap = kmap_atomic(iv.bv_page);
 201                         p = pmap + iv.bv_offset;
 202                         for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
 203                                 struct t10_pi_tuple *pi = p;
 204
 205                                 if (be32_to_cpu(pi->ref_tag) == ref_tag)
 206                                         pi->ref_tag = cpu_to_be32(virt);
 207                                 virt++;
 208                                 ref_tag++;
 209                                 intervals--;
 210                                 p += tuple_sz;
 211                         }
 212
 213                         kunmap_atomic(pmap);
 214                 }
 215         }
 216 }
 217
 218 static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
 219 {
 220         return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
 221 }
 222
 223 static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
 224 {
 225         return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
 226 }
 227
 228 static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
 229 {
 230         return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
 231 }
 232
 233 static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
 234 {
 235         return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
 236 }
 237
 238 /**
 239  * Type 3 does not have a reference tag so no remapping is required.
 240  */
 241 static void t10_pi_type3_prepare(struct request *rq)
 242 {
 243 }
 244
 245 /**
 246  * Type 3 does not have a reference tag so no remapping is required.
 247  */
 248 static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
 249 {
 250 }
 251
 252 const struct blk_integrity_profile t10_pi_type1_crc = {
 253         .name                   = "T10-DIF-TYPE1-CRC",
 254         .generate_fn            = t10_pi_type1_generate_crc,
 255         .verify_fn              = t10_pi_type1_verify_crc,
 256         .prepare_fn             = t10_pi_type1_prepare,
 257         .complete_fn            = t10_pi_type1_complete,
 258 };
 259 EXPORT_SYMBOL(t10_pi_type1_crc);
 260
 261 const struct blk_integrity_profile t10_pi_type1_ip = {
 262         .name                   = "T10-DIF-TYPE1-IP",
 263         .generate_fn            = t10_pi_type1_generate_ip,
 264         .verify_fn              = t10_pi_type1_verify_ip,
 265         .prepare_fn             = t10_pi_type1_prepare,
 266         .complete_fn            = t10_pi_type1_complete,
 267 };
 268 EXPORT_SYMBOL(t10_pi_type1_ip);
 269
 270 const struct blk_integrity_profile t10_pi_type3_crc = {
 271         .name                   = "T10-DIF-TYPE3-CRC",
 272         .generate_fn            = t10_pi_type3_generate_crc,
 273         .verify_fn              = t10_pi_type3_verify_crc,
 274         .prepare_fn             = t10_pi_type3_prepare,
 275         .complete_fn            = t10_pi_type3_complete,
 276 };
 277 EXPORT_SYMBOL(t10_pi_type3_crc);
 278
 279 const struct blk_integrity_profile t10_pi_type3_ip = {
 280         .name                   = "T10-DIF-TYPE3-IP",
 281         .generate_fn            = t10_pi_type3_generate_ip,
 282         .verify_fn              = t10_pi_type3_verify_ip,
 283         .prepare_fn             = t10_pi_type3_prepare,
 284         .complete_fn            = t10_pi_type3_complete,
 285 };
 286 EXPORT_SYMBOL(t10_pi_type3_ip);