summaryrefslogtreecommitdiff
path: root/block/t10-pi.c
blob: 0c0094609dd6307c608ff4b562747b661c82f332 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
// SPDX-License-Identifier: GPL-2.0
/*
 * t10_pi.c - Functions for generating and verifying T10 Protection
 *	      Information.
 */

#include <linux/t10-pi.h>
#include <linux/blkdev.h>
#include <linux/crc-t10dif.h>
#include <net/checksum.h>

typedef __be16 (csum_fn) (void *, unsigned int);

static __be16 t10_pi_crc_fn(void *data, unsigned int len)
{
	return cpu_to_be16(crc_t10dif(data, len));
}

static __be16 t10_pi_ip_fn(void *data, unsigned int len)
{
	return (__force __be16)ip_compute_csum(data, len);
}

/*
 * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
 * 16 bit app tag, 32 bit reference tag. Type 3 does not define the ref
 * tag.
 */
static blk_status_t t10_pi_generate(struct blk_integrity_iter *iter,
		csum_fn *fn, unsigned int type)
{
	unsigned int i;

	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
		struct t10_pi_tuple *pi = iter->prot_buf;

		pi->guard_tag = fn(iter->data_buf, iter->interval);
		pi->app_tag = 0;

		if (type == 1)
			pi->ref_tag = cpu_to_be32(lower_32_bits(iter->seed));
		else
			pi->ref_tag = 0;

		iter->data_buf += iter->interval;
		iter->prot_buf += sizeof(struct t10_pi_tuple);
		iter->seed++;
	}

	return BLK_STS_OK;
}

static blk_status_t t10_pi_verify(struct blk_integrity_iter *iter,
		csum_fn *fn, unsigned int type)
{
	unsigned int i;

	for (i = 0 ; i < iter->data_size ; i += iter->interval) {
		struct t10_pi_tuple *pi = iter->prot_buf;
		__be16 csum;

		switch (type) {
		case 1:
		case 2:
			if (pi->app_tag == T10_PI_APP_ESCAPE)
				goto next;

			if (be32_to_cpu(pi->ref_tag) !=
			    lower_32_bits(iter->seed)) {
				pr_err("%s: ref tag error at location %llu " \
				       "(rcvd %u)\n", iter->disk_name,
				       (unsigned long long)
				       iter->seed, be32_to_cpu(pi->ref_tag));
				return BLK_STS_PROTECTION;
			}
			break;
		case 3:
			if (pi->app_tag == T10_PI_APP_ESCAPE &&
			    pi->ref_tag == T10_PI_REF_ESCAPE)
				goto next;
			break;
		}

		csum = fn(iter->data_buf, iter->interval);

		if (pi->guard_tag != csum) {
			pr_err("%s: guard tag error at sector %llu " \
			       "(rcvd %04x, want %04x)\n", iter->disk_name,
			       (unsigned long long)iter->seed,
			       be16_to_cpu(pi->guard_tag), be16_to_cpu(csum));
			return BLK_STS_PROTECTION;
		}

next:
		iter->data_buf += iter->interval;
		iter->prot_buf += sizeof(struct t10_pi_tuple);
		iter->seed++;
	}

	return BLK_STS_OK;
}

static blk_status_t t10_pi_type1_generate_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_crc_fn, 1);
}

static blk_status_t t10_pi_type1_generate_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_ip_fn, 1);
}

static blk_status_t t10_pi_type1_verify_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_crc_fn, 1);
}

static blk_status_t t10_pi_type1_verify_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_ip_fn, 1);
}

static blk_status_t t10_pi_type3_generate_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_crc_fn, 3);
}

static blk_status_t t10_pi_type3_generate_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_generate(iter, t10_pi_ip_fn, 3);
}

static blk_status_t t10_pi_type3_verify_crc(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_crc_fn, 3);
}

static blk_status_t t10_pi_type3_verify_ip(struct blk_integrity_iter *iter)
{
	return t10_pi_verify(iter, t10_pi_ip_fn, 3);
}

const struct blk_integrity_profile t10_pi_type1_crc = {
	.name			= "T10-DIF-TYPE1-CRC",
	.generate_fn		= t10_pi_type1_generate_crc,
	.verify_fn		= t10_pi_type1_verify_crc,
};
EXPORT_SYMBOL(t10_pi_type1_crc);

const struct blk_integrity_profile t10_pi_type1_ip = {
	.name			= "T10-DIF-TYPE1-IP",
	.generate_fn		= t10_pi_type1_generate_ip,
	.verify_fn		= t10_pi_type1_verify_ip,
};
EXPORT_SYMBOL(t10_pi_type1_ip);

const struct blk_integrity_profile t10_pi_type3_crc = {
	.name			= "T10-DIF-TYPE3-CRC",
	.generate_fn		= t10_pi_type3_generate_crc,
	.verify_fn		= t10_pi_type3_verify_crc,
};
EXPORT_SYMBOL(t10_pi_type3_crc);

const struct blk_integrity_profile t10_pi_type3_ip = {
	.name			= "T10-DIF-TYPE3-IP",
	.generate_fn		= t10_pi_type3_generate_ip,
	.verify_fn		= t10_pi_type3_verify_ip,
};
EXPORT_SYMBOL(t10_pi_type3_ip);

/**
 * t10_pi_prepare - prepare PI prior submitting request to device
 * @rq:              request with PI that should be prepared
 * @protection_type: PI type (Type 1/Type 2/Type 3)
 *
 * For Type 1/Type 2, the virtual start sector is the one that was
 * originally submitted by the block layer for the ref_tag usage. Due to
 * partitioning, MD/DM cloning, etc. the actual physical start sector is
 * likely to be different. Remap protection information to match the
 * physical LBA.
 *
 * Type 3 does not have a reference tag so no remapping is required.
 */
void t10_pi_prepare(struct request *rq, u8 protection_type)
{
	const int tuple_sz = rq->q->integrity.tuple_size;
	u32 ref_tag = t10_pi_ref_tag(rq);
	struct bio *bio;

	if (protection_type == T10_PI_TYPE3_PROTECTION)
		return;

	__rq_for_each_bio(bio, rq) {
		struct bio_integrity_payload *bip = bio_integrity(bio);
		u32 virt = bip_get_seed(bip) & 0xffffffff;
		struct bio_vec iv;
		struct bvec_iter iter;

		/* Already remapped? */
		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
			break;

		bip_for_each_vec(iv, bip, iter) {
			void *p, *pmap;
			unsigned int j;

			pmap = kmap_atomic(iv.bv_page);
			p = pmap + iv.bv_offset;
			for (j = 0; j < iv.bv_len; j += tuple_sz) {
				struct t10_pi_tuple *pi = p;

				if (be32_to_cpu(pi->ref_tag) == virt)
					pi->ref_tag = cpu_to_be32(ref_tag);
				virt++;
				ref_tag++;
				p += tuple_sz;
			}

			kunmap_atomic(pmap);
		}

		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
	}
}
EXPORT_SYMBOL(t10_pi_prepare);

/**
 * t10_pi_complete - prepare PI prior returning request to the block layer
 * @rq:              request with PI that should be prepared
 * @protection_type: PI type (Type 1/Type 2/Type 3)
 * @intervals:       total elements to prepare
 *
 * For Type 1/Type 2, the virtual start sector is the one that was
 * originally submitted by the block layer for the ref_tag usage. Due to
 * partitioning, MD/DM cloning, etc. the actual physical start sector is
 * likely to be different. Since the physical start sector was submitted
 * to the device, we should remap it back to virtual values expected by the
 * block layer.
 *
 * Type 3 does not have a reference tag so no remapping is required.
 */
void t10_pi_complete(struct request *rq, u8 protection_type,
		     unsigned int intervals)
{
	const int tuple_sz = rq->q->integrity.tuple_size;
	u32 ref_tag = t10_pi_ref_tag(rq);
	struct bio *bio;

	if (protection_type == T10_PI_TYPE3_PROTECTION)
		return;

	__rq_for_each_bio(bio, rq) {
		struct bio_integrity_payload *bip = bio_integrity(bio);
		u32 virt = bip_get_seed(bip) & 0xffffffff;
		struct bio_vec iv;
		struct bvec_iter iter;

		bip_for_each_vec(iv, bip, iter) {
			void *p, *pmap;
			unsigned int j;

			pmap = kmap_atomic(iv.bv_page);
			p = pmap + iv.bv_offset;
			for (j = 0; j < iv.bv_len && intervals; j += tuple_sz) {
				struct t10_pi_tuple *pi = p;

				if (be32_to_cpu(pi->ref_tag) == ref_tag)
					pi->ref_tag = cpu_to_be32(virt);
				virt++;
				ref_tag++;
				intervals--;
				p += tuple_sz;
			}

			kunmap_atomic(pmap);
		}
	}
}
EXPORT_SYMBOL(t10_pi_complete);