xref: /openbmc/linux/block/t10-pi.c (revision e6f45ea2) 
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 
12 typedef __be16 (csum_fn) (void *, unsigned int);
13 
14 static __be16 t10_pi_crc_fn(void *data, unsigned int len)
15 {
16 	return cpu_to_be16(crc_t10dif(data, len));
17 }
18 
19 static __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  */
29 static 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 
53 static 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 
93 next:
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 
102 static 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 
107 static 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 
112 static 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 
117 static 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  */
132 static 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  */
183 static 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 
218 static 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 
223 static 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 
228 static 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 
233 static 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  */
241 static 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  */
248 static void t10_pi_type3_complete(struct request *rq, unsigned int nr_bytes)
249 {
250 }
251 
252 const 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 };
259 EXPORT_SYMBOL(t10_pi_type1_crc);
260 
261 const 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 };
268 EXPORT_SYMBOL(t10_pi_type1_ip);
269 
270 const 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 };
277 EXPORT_SYMBOL(t10_pi_type3_crc);
278 
279 const 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 };
286 EXPORT_SYMBOL(t10_pi_type3_ip);
287