Merge tag 'sound-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai...
[sfrench/cifs-2.6.git] / 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 const __be16 APP_ESCAPE = (__force __be16) 0xffff;
32 static const __be32 REF_ESCAPE = (__force __be32) 0xffffffff;
33
34 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
35 {
36         return cpu_to_be16(crc_t10dif(data, len));
37 }
38
39 static __be16 t10_pi_ip_fn(void *data, unsigned int len)
40 {
41         return (__force __be16)ip_compute_csum(data, len);
42 }
43
44 /*
45  * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
46  * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
47  * tag.
48  */
49 static int t10_pi_generate(struct blk_integrity_iter *iter, csum_fn *fn,
50                            unsigned int type)
51 {
52         unsigned int i;
53
54         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
55                 struct t10_pi_tuple *pi = iter->prot_buf;
56
57                 pi->guard_tag = fn(iter->data_buf, iter->interval);
58                 pi->app_tag = 0;
59
60                 if (type == 1)
61                         pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
62                 else
63                         pi->ref_tag = 0;
64
65                 iter->data_buf += iter->interval;
66                 iter->prot_buf += sizeof(struct t10_pi_tuple);
67                 iter->seed++;
68         }
69
70         return 0;
71 }
72
73 static int t10_pi_verify(struct blk_integrity_iter *iter, csum_fn *fn,
74                                 unsigned int type)
75 {
76         unsigned int i;
77
78         for (i = 0 ; i < iter->data_size ; i += iter->interval) {
79                 struct t10_pi_tuple *pi = iter->prot_buf;
80                 __be16 csum;
81
82                 switch (type) {
83                 case 1:
84                 case 2:
85                         if (pi->app_tag == APP_ESCAPE)
86                                 goto next;
87
88                         if (be32_to_cpu(pi->ref_tag) !=
89                             lower_32_bits(iter->seed)) {
90                                 pr_err("%s: ref tag error at location %llu " \
91                                        "(rcvd %u)\n", iter->disk_name,
92                                        (unsigned long long)
93                                        iter->seed, be32_to_cpu(pi->ref_tag));
94                                 return -EILSEQ;
95                         }
96                         break;
97                 case 3:
98                         if (pi->app_tag == APP_ESCAPE &&
99                             pi->ref_tag == REF_ESCAPE)
100                                 goto next;
101                         break;
102                 }
103
104                 csum = fn(iter->data_buf, iter->interval);
105
106                 if (pi->guard_tag != csum) {
107                         pr_err("%s: guard tag error at sector %llu " \
108                                "(rcvd %04x, want %04x)\n", iter->disk_name,
109                                (unsigned long long)iter->seed,
110                                be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
111                         return -EILSEQ;
112                 }
113
114 next:
115                 iter->data_buf += iter->interval;
116                 iter->prot_buf += sizeof(struct t10_pi_tuple);
117                 iter->seed++;
118         }
119
120         return 0;
121 }
122
123 static int t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
124 {
125         return t10_pi_generate(iter, t10_pi_crc_fn, 1);
126 }
127
128 static int t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
129 {
130         return t10_pi_generate(iter, t10_pi_ip_fn, 1);
131 }
132
133 static int t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
134 {
135         return t10_pi_verify(iter, t10_pi_crc_fn, 1);
136 }
137
138 static int t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
139 {
140         return t10_pi_verify(iter, t10_pi_ip_fn, 1);
141 }
142
143 static int t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
144 {
145         return t10_pi_generate(iter, t10_pi_crc_fn, 3);
146 }
147
148 static int t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
149 {
150         return t10_pi_generate(iter, t10_pi_ip_fn, 3);
151 }
152
153 static int t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
154 {
155         return t10_pi_verify(iter, t10_pi_crc_fn, 3);
156 }
157
158 static int t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
159 {
160         return t10_pi_verify(iter, t10_pi_ip_fn, 3);
161 }
162
163 struct blk_integrity t10_pi_type1_crc = {
164         .name                   = "T10-DIF-TYPE1-CRC",
165         .generate_fn            = t10_pi_type1_generate_crc,
166         .verify_fn              = t10_pi_type1_verify_crc,
167         .tuple_size             = sizeof(struct t10_pi_tuple),
168         .tag_size               = 0,
169 };
170 EXPORT_SYMBOL(t10_pi_type1_crc);
171
172 struct blk_integrity t10_pi_type1_ip = {
173         .name                   = "T10-DIF-TYPE1-IP",
174         .generate_fn            = t10_pi_type1_generate_ip,
175         .verify_fn              = t10_pi_type1_verify_ip,
176         .tuple_size             = sizeof(struct t10_pi_tuple),
177         .tag_size               = 0,
178 };
179 EXPORT_SYMBOL(t10_pi_type1_ip);
180
181 struct blk_integrity t10_pi_type3_crc = {
182         .name                   = "T10-DIF-TYPE3-CRC",
183         .generate_fn            = t10_pi_type3_generate_crc,
184         .verify_fn              = t10_pi_type3_verify_crc,
185         .tuple_size             = sizeof(struct t10_pi_tuple),
186         .tag_size               = 0,
187 };
188 EXPORT_SYMBOL(t10_pi_type3_crc);
189
190 struct blk_integrity t10_pi_type3_ip = {
191         .name                   = "T10-DIF-TYPE3-IP",
192         .generate_fn            = t10_pi_type3_generate_ip,
193         .verify_fn              = t10_pi_type3_verify_ip,
194         .tuple_size             = sizeof(struct t10_pi_tuple),
195         .tag_size               = 0,
196 };
197 EXPORT_SYMBOL(t10_pi_type3_ip);