xref: /kernel/linux/linux-5.10/block/t10-pi.c (revision 8c2ecf20) 
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");
286