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