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 <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                         void *p, *pmap;
 151                         unsigned int j;
 152
 153                         pmap = kmap_atomic(iv.bv_page);
 154                         p = pmap + iv.bv_offset;
 155                         for (j = 0; j < iv.bv_len; j += tuple_sz) {
 156                                 struct t10_pi_tuple *pi = p;
 157
 158                                 if (be32_to_cpu(pi->ref_tag) == virt)
 159                                         pi->ref_tag = cpu_to_be32(ref_tag);
 160                                 virt++;
 161                                 ref_tag++;
 162                                 p += tuple_sz;
 163                         }
 164
 165                         kunmap_atomic(pmap);
 166                 }
 167
 168                 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
 169         }
 170 }
 171
 172 /**
 173  * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
 174  * @rq:              request with PI that should be prepared
 175  * @nr_bytes:        total bytes to prepare
 176  *
 177  * For Type 1/Type 2, the virtual start sector is the one that was
 178  * originally submitted by the block layer for the ref_tag usage. Due to
 179  * partitioning, MD/DM cloning, etc. the actual physical start sector is
 180  * likely to be different. Since the physical start sector was submitted
 181  * to the device, we should remap it back to virtual values expected by the
 182  * block layer.
 183  */
 184 static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
 185 {
 186         unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
 187         const int tuple_sz = rq->q->integrity.tuple_size;
 188         u32 ref_tag = t10_pi_ref_tag(rq);
 189         struct bio *bio;
 190
 191         __rq_for_each_bio(bio, rq) {
 192                 struct bio_integrity_payload *bip = bio_integrity(bio);
 193                 u32 virt = bip_get_seed(bip) & 0xffffffff;
 194                 struct bio_vec iv;
 195                 struct bvec_iter iter;
 196
 197                 bip_for_each_vec(iv, bip, iter) {
 198                         void *p, *pmap;
 199                         unsigned int j;
 200
 201                         pmap = kmap_atomic(iv.bv_page);
 202                         p = pmap + iv.bv_offset;
 203                         for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
 204                                 struct t10_pi_tuple *pi = p;
 205
 206                                 if (be32_to_cpu(pi->ref_tag) == ref_tag)
 207                                         pi->ref_tag = cpu_to_be32(virt);
 208                                 virt++;
 209                                 ref_tag++;
 210                                 intervals--;
 211                                 p += tuple_sz;
 212                         }
 213
 214                         kunmap_atomic(pmap);
 215                 }
 216         }
 217 }
 218
 219 static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
 220 {
 221         return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
 222 }
 223
 224 static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
 225 {
 226         return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
 227 }
 228
 229 static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
 230 {
 231         return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
 232 }
 233
 234 static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
 235 {
 236         return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
 237 }
 238
 239 /* Type 3 does not have a reference tag so no remapping is required. */
 240 static void t10_pi_type3_prepare(struct request *rq)
 241 {
 242 }
 243
 244 /* Type 3 does not have a reference tag so no remapping is required. */
 245 static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
 246 {
 247 }
 248
 249 const struct blk_integrity_profile t10_pi_type1_crc = {
 250         .name                   = "T10-DIF-TYPE1-CRC",
 251         .generate_fn            = t10_pi_type1_generate_crc,
 252         .verify_fn              = t10_pi_type1_verify_crc,
 253         .prepare_fn             = t10_pi_type1_prepare,
 254         .complete_fn            = t10_pi_type1_complete,
 255 };
 256 EXPORT_SYMBOL(t10_pi_type1_crc);
 257
 258 const struct blk_integrity_profile t10_pi_type1_ip = {
 259         .name                   = "T10-DIF-TYPE1-IP",
 260         .generate_fn            = t10_pi_type1_generate_ip,
 261         .verify_fn              = t10_pi_type1_verify_ip,
 262         .prepare_fn             = t10_pi_type1_prepare,
 263         .complete_fn            = t10_pi_type1_complete,
 264 };
 265 EXPORT_SYMBOL(t10_pi_type1_ip);
 266
 267 const struct blk_integrity_profile t10_pi_type3_crc = {
 268         .name                   = "T10-DIF-TYPE3-CRC",
 269         .generate_fn            = t10_pi_type3_generate_crc,
 270         .verify_fn              = t10_pi_type3_verify_crc,
 271         .prepare_fn             = t10_pi_type3_prepare,
 272         .complete_fn            = t10_pi_type3_complete,
 273 };
 274 EXPORT_SYMBOL(t10_pi_type3_crc);
 275
 276 const struct blk_integrity_profile t10_pi_type3_ip = {
 277         .name                   = "T10-DIF-TYPE3-IP",
 278         .generate_fn            = t10_pi_type3_generate_ip,
 279         .verify_fn              = t10_pi_type3_verify_ip,
 280         .prepare_fn             = t10_pi_type3_prepare,
 281         .complete_fn            = t10_pi_type3_complete,
 282 };
 283 EXPORT_SYMBOL(t10_pi_type3_ip);
 284
 285 MODULE_LICENSE("GPL");