block/t10-pi.c

   1 /*
   2  * t10_pi.c - Functions for generating and verifying T10 Protection
   3  *            Information.
   4  *
   5  * Copyright (C) 2007, 2008, 2014 Oracle Corporation
   6  * Written by: Martin K. Petersen <martin.petersen@oracle.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License version
  10  * 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; see the file COPYING.  If not, write to
  19  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
  20  * USA.
  21  *
  22  */
  23
  24 #include <linux/t10-pi.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/crc-t10dif.h>
  27 #include <net/checksum.h>
  28
  29 typedef __be16 (csum_fn) (void *, unsigned int);
  30
  31 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
  32 {
  33         return cpu_to_be16(crc_t10dif(data, len));
  34 }
  35
  36 static __be16 t10_pi_ip_fn(void *data, unsigned int len)
  37 {
  38         return (__force __be16)ip_compute_csum(data, len);
  39 }
  40
  41 /*
  42  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
  43  * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
  44  * tag.
  45  */
  46 static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
  47                 csum_fn *fn, unsigned int type)
  48 {
  49         unsigned int i;
  50
  51         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  52                 struct t10_pi_tuple *pi = iter->prot_buf;
  53
  54                 pi->guard_tag = fn(iter->data_buf, iter->interval);
  55                 pi->app_tag = 0;
  56
  57                 if (type == 1)
  58                         pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
  59                 else
  60                         pi->ref_tag = 0;
  61
  62                 iter->data_buf += iter->interval;
  63                 iter->prot_buf += sizeof(struct t10_pi_tuple);
  64                 iter->seed++;
  65         }
  66
  67         return BLK_STS_OK;
  68 }
  69
  70 static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
  71                 csum_fn *fn, unsigned int type)
  72 {
  73         unsigned int i;
  74
  75         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
  76                 struct t10_pi_tuple *pi = iter->prot_buf;
  77                 __be16 csum;
  78
  79                 switch (type) {
  80                 case 1:
  81                 case 2:
  82                         if (pi->app_tag == T10_PI_APP_ESCAPE)
  83                                 goto next;
  84
  85                         if (be32_to_cpu(pi->ref_tag) !=
  86                             lower_32_bits(iter->seed)) {
  87                                 pr_err("%s: ref tag error at location %llu " \
  88                                        "(rcvd %u)\n", iter->disk_name,
  89                                        (unsigned long long)
  90                                        iter->seed, be32_to_cpu(pi->ref_tag));
  91                                 return BLK_STS_PROTECTION;
  92                         }
  93                         break;
  94                 case 3:
  95                         if (pi->app_tag == T10_PI_APP_ESCAPE &&
  96                             pi->ref_tag == T10_PI_REF_ESCAPE)
  97                                 goto next;
  98                         break;
  99                 }
 100
 101                 csum = fn(iter->data_buf, iter->interval);
 102
 103                 if (pi->guard_tag != csum) {
 104                         pr_err("%s: guard tag error at sector %llu " \
 105                                "(rcvd %04x, want %04x)\n", iter->disk_name,
 106                                (unsigned long long)iter->seed,
 107                                be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
 108                         return BLK_STS_PROTECTION;
 109                 }
 110
 111 next:
 112                 iter->data_buf += iter->interval;
 113                 iter->prot_buf += sizeof(struct t10_pi_tuple);
 114                 iter->seed++;
 115         }
 116
 117         return BLK_STS_OK;
 118 }
 119
 120 static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
 121 {
 122         return t10_pi_generate(iter, t10_pi_crc_fn, 1);
 123 }
 124
 125 static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
 126 {
 127         return t10_pi_generate(iter, t10_pi_ip_fn, 1);
 128 }
 129
 130 static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
 131 {
 132         return t10_pi_verify(iter, t10_pi_crc_fn, 1);
 133 }
 134
 135 static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
 136 {
 137         return t10_pi_verify(iter, t10_pi_ip_fn, 1);
 138 }
 139
 140 static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
 141 {
 142         return t10_pi_generate(iter, t10_pi_crc_fn, 3);
 143 }
 144
 145 static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
 146 {
 147         return t10_pi_generate(iter, t10_pi_ip_fn, 3);
 148 }
 149
 150 static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
 151 {
 152         return t10_pi_verify(iter, t10_pi_crc_fn, 3);
 153 }
 154
 155 static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
 156 {
 157         return t10_pi_verify(iter, t10_pi_ip_fn, 3);
 158 }
 159
 160 const struct blk_integrity_profile t10_pi_type1_crc = {
 161         .name                   = "T10-DIF-TYPE1-CRC",
 162         .generate_fn            = t10_pi_type1_generate_crc,
 163         .verify_fn              = t10_pi_type1_verify_crc,
 164 };
 165 EXPORT_SYMBOL(t10_pi_type1_crc);
 166
 167 const struct blk_integrity_profile t10_pi_type1_ip = {
 168         .name                   = "T10-DIF-TYPE1-IP",
 169         .generate_fn            = t10_pi_type1_generate_ip,
 170         .verify_fn              = t10_pi_type1_verify_ip,
 171 };
 172 EXPORT_SYMBOL(t10_pi_type1_ip);
 173
 174 const struct blk_integrity_profile t10_pi_type3_crc = {
 175         .name                   = "T10-DIF-TYPE3-CRC",
 176         .generate_fn            = t10_pi_type3_generate_crc,
 177         .verify_fn              = t10_pi_type3_verify_crc,
 178 };
 179 EXPORT_SYMBOL(t10_pi_type3_crc);
 180
 181 const struct blk_integrity_profile t10_pi_type3_ip = {
 182         .name                   = "T10-DIF-TYPE3-IP",
 183         .generate_fn            = t10_pi_type3_generate_ip,
 184         .verify_fn              = t10_pi_type3_verify_ip,
 185 };
 186 EXPORT_SYMBOL(t10_pi_type3_ip);