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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 <net/checksum.h>
11
12typedef __be16 (csum_fn) (void *, unsigned int);
13
14static __be16 t10_pi_crc_fn(void *data, unsigned int len)
15{
16 return cpu_to_be16(crc_t10dif(data, len));
17}
18
19static __be16 t10_pi_ip_fn(void *data, unsigned int len)
20{
21 return (__force __be16)ip_compute_csum(data, len);
22}
23
24/*
25 * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
26 * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
27 * tag.
28 */
29static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
30 csum_fn *fn, enum t10_dif_type type)
31{
32 unsigned int i;
33
34 for (i = 0 ; i < iter->data_size ; i += iter->interval) {
35 struct t10_pi_tuple *pi = iter->prot_buf;
36
37 pi->guard_tag = fn(iter->data_buf, iter->interval);
38 pi->app_tag = 0;
39
40 if (type == T10_PI_TYPE1_PROTECTION)
41 pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
42 else
43 pi->ref_tag = 0;
44
45 iter->data_buf += iter->interval;
46 iter->prot_buf += sizeof(struct t10_pi_tuple);
47 iter->seed++;
48 }
49
50 return BLK_STS_OK;
51}
52
53static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
54 csum_fn *fn, enum t10_dif_type type)
55{
56 unsigned int i;
57
58 BUG_ON(type == T10_PI_TYPE0_PROTECTION);
59
60 for (i = 0 ; i < iter->data_size ; i += iter->interval) {
61 struct t10_pi_tuple *pi = iter->prot_buf;
62 __be16 csum;
63
64 if (type == T10_PI_TYPE1_PROTECTION ||
65 type == T10_PI_TYPE2_PROTECTION) {
66 if (pi->app_tag == T10_PI_APP_ESCAPE)
67 goto next;
68
69 if (be32_to_cpu(pi->ref_tag) !=
70 lower_32_bits(iter->seed)) {
71 pr_err("%s: ref tag error at location %llu " \
72 "(rcvd %u)\n", iter->disk_name,
73 (unsigned long long)
74 iter->seed, be32_to_cpu(pi->ref_tag));
75 return BLK_STS_PROTECTION;
76 }
77 } else if (type == T10_PI_TYPE3_PROTECTION) {
78 if (pi->app_tag == T10_PI_APP_ESCAPE &&
79 pi->ref_tag == T10_PI_REF_ESCAPE)
80 goto next;
81 }
82
83 csum = fn(iter->data_buf, iter->interval);
84
85 if (pi->guard_tag != csum) {
86 pr_err("%s: guard tag error at sector %llu " \
87 "(rcvd %04x, want %04x)\n", iter->disk_name,
88 (unsigned long long)iter->seed,
89 be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
90 return BLK_STS_PROTECTION;
91 }
92
93next:
94 iter->data_buf += iter->interval;
95 iter->prot_buf += sizeof(struct t10_pi_tuple);
96 iter->seed++;
97 }
98
99 return BLK_STS_OK;
100}
101
102static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
103{
104 return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
105}
106
107static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
108{
109 return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
110}
111
112static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
113{
114 return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE1_PROTECTION);
115}
116
117static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
118{
119 return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE1_PROTECTION);
120}
121
122/**
123 * t10_pi_type1_prepare - prepare PI prior submitting request to device
124 * @rq: request with PI that should be prepared
125 *
126 * For Type 1/Type 2, the virtual start sector is the one that was
127 * originally submitted by the block layer for the ref_tag usage. Due to
128 * partitioning, MD/DM cloning, etc. the actual physical start sector is
129 * likely to be different. Remap protection information to match the
130 * physical LBA.
131 */
132static void t10_pi_type1_prepare(struct request *rq)
133{
134 const int tuple_sz = rq->q->integrity.tuple_size;
135 u32 ref_tag = t10_pi_ref_tag(rq);
136 struct bio *bio;
137
138 __rq_for_each_bio(bio, rq) {
139 struct bio_integrity_payload *bip = bio_integrity(bio);
140 u32 virt = bip_get_seed(bip) & 0xffffffff;
141 struct bio_vec iv;
142 struct bvec_iter iter;
143
144 /* Already remapped? */
145 if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
146 break;
147
148 bip_for_each_vec(iv, bip, iter) {
149 void *p, *pmap;
150 unsigned int j;
151
152 pmap = kmap_atomic(iv.bv_page);
153 p = pmap + iv.bv_offset;
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
164 kunmap_atomic(pmap);
165 }
166
167 bip->bip_flags |= BIP_MAPPED_INTEGRITY;
168 }
169}
170
171/**
172 * t10_pi_type1_complete - prepare PI prior returning request to the blk layer
173 * @rq: request with PI that should be prepared
174 * @nr_bytes: total bytes to prepare
175 *
176 * For Type 1/Type 2, the virtual start sector is the one that was
177 * originally submitted by the block layer for the ref_tag usage. Due to
178 * partitioning, MD/DM cloning, etc. the actual physical start sector is
179 * likely to be different. Since the physical start sector was submitted
180 * to the device, we should remap it back to virtual values expected by the
181 * block layer.
182 */
183static void t10_pi_type1_complete(struct request *rq, unsigned int nr_bytes)
184{
185 unsigned intervals = nr_bytes >> rq->q->integrity.interval_exp;
186 const int tuple_sz = rq->q->integrity.tuple_size;
187 u32 ref_tag = t10_pi_ref_tag(rq);
188 struct bio *bio;
189
190 __rq_for_each_bio(bio, rq) {
191 struct bio_integrity_payload *bip = bio_integrity(bio);
192 u32 virt = bip_get_seed(bip) & 0xffffffff;
193 struct bio_vec iv;
194 struct bvec_iter iter;
195
196 bip_for_each_vec(iv, bip, iter) {
197 void *p, *pmap;
198 unsigned int j;
199
200 pmap = kmap_atomic(iv.bv_page);
201 p = pmap + iv.bv_offset;
202 for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
203 struct t10_pi_tuple *pi = p;
204
205 if (be32_to_cpu(pi->ref_tag) == ref_tag)
206 pi->ref_tag = cpu_to_be32(virt);
207 virt++;
208 ref_tag++;
209 intervals--;
210 p += tuple_sz;
211 }
212
213 kunmap_atomic(pmap);
214 }
215 }
216}
217
218static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
219{
220 return t10_pi_generate(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
221}
222
223static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
224{
225 return t10_pi_generate(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
226}
227
228static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
229{
230 return t10_pi_verify(iter, t10_pi_crc_fn, T10_PI_TYPE3_PROTECTION);
231}
232
233static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
234{
235 return t10_pi_verify(iter, t10_pi_ip_fn, T10_PI_TYPE3_PROTECTION);
236}
237
238/**
239 * Type 3 does not have a reference tag so no remapping is required.
240 */
241static void t10_pi_type3_prepare(struct request *rq)
242{
243}
244
245/**
246 * Type 3 does not have a reference tag so no remapping is required.
247 */
248static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
249{
250}
251
252const struct blk_integrity_profile t10_pi_type1_crc = {
253 .name = "T10-DIF-TYPE1-CRC",
254 .generate_fn = t10_pi_type1_generate_crc,
255 .verify_fn = t10_pi_type1_verify_crc,
256 .prepare_fn = t10_pi_type1_prepare,
257 .complete_fn = t10_pi_type1_complete,
258};
259EXPORT_SYMBOL(t10_pi_type1_crc);
260
261const struct blk_integrity_profile t10_pi_type1_ip = {
262 .name = "T10-DIF-TYPE1-IP",
263 .generate_fn = t10_pi_type1_generate_ip,
264 .verify_fn = t10_pi_type1_verify_ip,
265 .prepare_fn = t10_pi_type1_prepare,
266 .complete_fn = t10_pi_type1_complete,
267};
268EXPORT_SYMBOL(t10_pi_type1_ip);
269
270const struct blk_integrity_profile t10_pi_type3_crc = {
271 .name = "T10-DIF-TYPE3-CRC",
272 .generate_fn = t10_pi_type3_generate_crc,
273 .verify_fn = t10_pi_type3_verify_crc,
274 .prepare_fn = t10_pi_type3_prepare,
275 .complete_fn = t10_pi_type3_complete,
276};
277EXPORT_SYMBOL(t10_pi_type3_crc);
278
279const struct blk_integrity_profile t10_pi_type3_ip = {
280 .name = "T10-DIF-TYPE3-IP",
281 .generate_fn = t10_pi_type3_generate_ip,
282 .verify_fn = t10_pi_type3_verify_ip,
283 .prepare_fn = t10_pi_type3_prepare,
284 .complete_fn = t10_pi_type3_complete,
285};
286EXPORT_SYMBOL(t10_pi_type3_ip);