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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 <linux/module.h>
11#include <net/checksum.h>
12
13typedef __be16 (csum_fn) (void *, unsigned int);
14
15static __be16 t10_pi_crc_fn(void *data, unsigned int len)
16{
17 return cpu_to_be16(crc_t10dif(data, len));
18}
19
20static __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 */
30static 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
54static 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
94next:
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
103static 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
108static 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
113static 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
118static 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 */
133static 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 */
184static 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
219static 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
224static 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
229static 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
234static 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. */
240static 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. */
245static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
246{
247}
248
249const 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};
256EXPORT_SYMBOL(t10_pi_type1_crc);
257
258const 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};
265EXPORT_SYMBOL(t10_pi_type1_ip);
266
267const 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};
274EXPORT_SYMBOL(t10_pi_type3_crc);
275
276const 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};
283EXPORT_SYMBOL(t10_pi_type3_ip);
284
285MODULE_LICENSE("GPL");