diff options
Diffstat (limited to 'block/t10-pi.c')
| -rw-r--r-- | block/t10-pi.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/block/t10-pi.c b/block/t10-pi.c new file mode 100644 index 0000000..24d6e97 --- /dev/null +++ b/block/t10-pi.c @@ -0,0 +1,197 @@ +/* + * t10_pi.c - Functions for generating and verifying T10 Protection + * Information. + * + * Copyright (C) 2007, 2008, 2014 Oracle Corporation + * Written by: Martin K. Petersen <martin.petersen@oracle.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version + * 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, + * USA. + * + */ + +#include <linux/t10-pi.h> +#include <linux/blkdev.h> +#include <linux/crc-t10dif.h> +#include <net/checksum.h> + +typedef __be16 (csum_fn) (void *, unsigned int); + +static const __be16 APP_ESCAPE = (__force __be16) 0xffff; +static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff; + +static __be16 t10_pi_crc_fn(void *data, unsigned int len) +{ + return cpu_to_be16(crc_t10dif(data, len)); +} + +static __be16 t10_pi_ip_fn(void *data, unsigned int len) +{ + return (__force __be16)ip_compute_csum(data, len); +} + +/* + * Type 1 and Type 2 protection use the same format: 16 bit guard tag, + * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref + * tag. + */ +static int t10_pi_generate(struct blk_integrity_iter *iter, csum_fn *fn, + unsigned int type) +{ + unsigned int i; + + for (i = 0 ; i < iter->data_size ; i += iter->interval) { + struct t10_pi_tuple *pi = iter->prot_buf; + + pi->guard_tag = fn(iter->data_buf, iter->interval); + pi->app_tag = 0; + + if (type == 1) + pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed)); + else + pi->ref_tag = 0; + + iter->data_buf += iter->interval; + iter->prot_buf += sizeof(struct t10_pi_tuple); + iter->seed++; + } + + return 0; +} + +static int t10_pi_verify(struct blk_integrity_iter *iter, csum_fn *fn, + unsigned int type) +{ + unsigned int i; + + for (i = 0 ; i < iter->data_size ; i += iter->interval) { + struct t10_pi_tuple *pi = iter->prot_buf; + __be16 csum; + + switch (type) { + case 1: + case 2: + if (pi->app_tag == APP_ESCAPE) + goto next; + + if (be32_to_cpu(pi->ref_tag) != + lower_32_bits(iter->seed)) { + pr_err("%s: ref tag error at location %llu " \ + "(rcvd %u)\n", iter->disk_name, + (unsigned long long) + iter->seed, be32_to_cpu(pi->ref_tag)); + return -EILSEQ; + } + break; + case 3: + if (pi->app_tag == APP_ESCAPE && + pi->ref_tag == REF_ESCAPE) + goto next; + break; + } + + csum = fn(iter->data_buf, iter->interval); + + if (pi->guard_tag != csum) { + pr_err("%s: guard tag error at sector %llu " \ + "(rcvd %04x, want %04x)\n", iter->disk_name, + (unsigned long long)iter->seed, + be16_to_cpu(pi->guard_tag), be16_to_cpu(csum)); + return -EILSEQ; + } + +next: + iter->data_buf += iter->interval; + iter->prot_buf += sizeof(struct t10_pi_tuple); + iter->seed++; + } + + return 0; +} + +static int t10_pi_type1_generate_crc(struct blk_integrity_iter *iter) +{ + return t10_pi_generate(iter, t10_pi_crc_fn, 1); +} + +static int t10_pi_type1_generate_ip(struct blk_integrity_iter *iter) +{ + return t10_pi_generate(iter, t10_pi_ip_fn, 1); +} + +static int t10_pi_type1_verify_crc(struct blk_integrity_iter *iter) +{ + return t10_pi_verify(iter, t10_pi_crc_fn, 1); +} + +static int t10_pi_type1_verify_ip(struct blk_integrity_iter *iter) +{ + return t10_pi_verify(iter, t10_pi_ip_fn, 1); +} + +static int t10_pi_type3_generate_crc(struct blk_integrity_iter *iter) +{ + return t10_pi_generate(iter, t10_pi_crc_fn, 3); +} + +static int t10_pi_type3_generate_ip(struct blk_integrity_iter *iter) +{ + return t10_pi_generate(iter, t10_pi_ip_fn, 3); +} + +static int t10_pi_type3_verify_crc(struct blk_integrity_iter *iter) +{ + return t10_pi_verify(iter, t10_pi_crc_fn, 3); +} + +static int t10_pi_type3_verify_ip(struct blk_integrity_iter *iter) +{ + return t10_pi_verify(iter, t10_pi_ip_fn, 3); +} + +struct blk_integrity t10_pi_type1_crc = { + .name = "T10-DIF-TYPE1-CRC", + .generate_fn = t10_pi_type1_generate_crc, + .verify_fn = t10_pi_type1_verify_crc, + .tuple_size = sizeof(struct t10_pi_tuple), + .tag_size = 0, +}; +EXPORT_SYMBOL(t10_pi_type1_crc); + +struct blk_integrity t10_pi_type1_ip = { + .name = "T10-DIF-TYPE1-IP", + .generate_fn = t10_pi_type1_generate_ip, + .verify_fn = t10_pi_type1_verify_ip, + .tuple_size = sizeof(struct t10_pi_tuple), + .tag_size = 0, +}; +EXPORT_SYMBOL(t10_pi_type1_ip); + +struct blk_integrity t10_pi_type3_crc = { + .name = "T10-DIF-TYPE3-CRC", + .generate_fn = t10_pi_type3_generate_crc, + .verify_fn = t10_pi_type3_verify_crc, + .tuple_size = sizeof(struct t10_pi_tuple), + .tag_size = 0, +}; +EXPORT_SYMBOL(t10_pi_type3_crc); + +struct blk_integrity t10_pi_type3_ip = { + .name = "T10-DIF-TYPE3-IP", + .generate_fn = t10_pi_type3_generate_ip, + .verify_fn = t10_pi_type3_verify_ip, + .tuple_size = sizeof(struct t10_pi_tuple), + .tag_size = 0, +}; +EXPORT_SYMBOL(t10_pi_type3_ip); |
