1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2007, 2008, 2009 Oracle Corporation
4 * Written by: Martin K. Petersen <martin.petersen@oracle.com>
5 *
6 * Automatically generate and verify integrity data on PI capable devices if the
7 * bio submitter didn't provide PI itself. This ensures that kernel verifies
8 * data integrity even if the file system (or other user of the block device) is
9 * not aware of PI.
10 */
11 #include <linux/blk-integrity.h>
12 #include <linux/t10-pi.h>
13 #include <linux/workqueue.h>
14 #include "blk.h"
15
16 struct bio_integrity_data {
17 struct bio *bio;
18 struct bvec_iter saved_bio_iter;
19 struct work_struct work;
20 struct bio_integrity_payload bip;
21 struct bio_vec bvec;
22 };
23
24 static struct kmem_cache *bid_slab;
25 static mempool_t bid_pool;
26 static struct workqueue_struct *kintegrityd_wq;
27
bio_integrity_finish(struct bio_integrity_data * bid)28 static void bio_integrity_finish(struct bio_integrity_data *bid)
29 {
30 bid->bio->bi_integrity = NULL;
31 bid->bio->bi_opf &= ~REQ_INTEGRITY;
32 bio_integrity_free_buf(&bid->bip);
33 mempool_free(bid, &bid_pool);
34 }
35
bio_integrity_verify_fn(struct work_struct * work)36 static void bio_integrity_verify_fn(struct work_struct *work)
37 {
38 struct bio_integrity_data *bid =
39 container_of(work, struct bio_integrity_data, work);
40 struct bio *bio = bid->bio;
41
42 blk_integrity_verify_iter(bio, &bid->saved_bio_iter);
43 bio_integrity_finish(bid);
44 bio_endio(bio);
45 }
46
47 #define BIP_CHECK_FLAGS (BIP_CHECK_GUARD | BIP_CHECK_REFTAG | BIP_CHECK_APPTAG)
bip_should_check(struct bio_integrity_payload * bip)48 static bool bip_should_check(struct bio_integrity_payload *bip)
49 {
50 return bip->bip_flags & BIP_CHECK_FLAGS;
51 }
52
bi_offload_capable(struct blk_integrity * bi)53 static bool bi_offload_capable(struct blk_integrity *bi)
54 {
55 return bi->metadata_size == bi->pi_tuple_size;
56 }
57
58 /**
59 * __bio_integrity_endio - Integrity I/O completion function
60 * @bio: Protected bio
61 *
62 * Normally I/O completion is done in interrupt context. However, verifying I/O
63 * integrity is a time-consuming task which must be run in process context.
64 *
65 * This function postpones completion accordingly.
66 */
__bio_integrity_endio(struct bio * bio)67 bool __bio_integrity_endio(struct bio *bio)
68 {
69 struct bio_integrity_payload *bip = bio_integrity(bio);
70 struct bio_integrity_data *bid =
71 container_of(bip, struct bio_integrity_data, bip);
72
73 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
74 bip_should_check(bip)) {
75 INIT_WORK(&bid->work, bio_integrity_verify_fn);
76 queue_work(kintegrityd_wq, &bid->work);
77 return false;
78 }
79
80 bio_integrity_finish(bid);
81 return true;
82 }
83
84 /**
85 * bio_integrity_prep - Prepare bio for integrity I/O
86 * @bio: bio to prepare
87 *
88 * Checks if the bio already has an integrity payload attached. If it does, the
89 * payload has been generated by another kernel subsystem, and we just pass it
90 * through.
91 * Otherwise allocates integrity payload and for writes the integrity metadata
92 * will be generated. For reads, the completion handler will verify the
93 * metadata.
94 */
bio_integrity_prep(struct bio * bio)95 bool bio_integrity_prep(struct bio *bio)
96 {
97 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
98 struct bio_integrity_data *bid;
99 bool set_flags = true;
100 gfp_t gfp = GFP_NOIO;
101
102 if (!bi)
103 return true;
104
105 if (!bio_sectors(bio))
106 return true;
107
108 /* Already protected? */
109 if (bio_integrity(bio))
110 return true;
111
112 switch (bio_op(bio)) {
113 case REQ_OP_READ:
114 if (bi->flags & BLK_INTEGRITY_NOVERIFY) {
115 if (bi_offload_capable(bi))
116 return true;
117 set_flags = false;
118 }
119 break;
120 case REQ_OP_WRITE:
121 /*
122 * Zero the memory allocated to not leak uninitialized kernel
123 * memory to disk for non-integrity metadata where nothing else
124 * initializes the memory.
125 */
126 if (bi->flags & BLK_INTEGRITY_NOGENERATE) {
127 if (bi_offload_capable(bi))
128 return true;
129 set_flags = false;
130 gfp |= __GFP_ZERO;
131 } else if (bi->metadata_size > bi->pi_tuple_size)
132 gfp |= __GFP_ZERO;
133 break;
134 default:
135 return true;
136 }
137
138 if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
139 return true;
140
141 bid = mempool_alloc(&bid_pool, GFP_NOIO);
142 bio_integrity_init(bio, &bid->bip, &bid->bvec, 1);
143 bid->bio = bio;
144 bid->bip.bip_flags |= BIP_BLOCK_INTEGRITY;
145 bio_integrity_alloc_buf(bio, gfp & __GFP_ZERO);
146
147 bip_set_seed(&bid->bip, bio->bi_iter.bi_sector);
148
149 if (set_flags) {
150 if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
151 bid->bip.bip_flags |= BIP_IP_CHECKSUM;
152 if (bi->csum_type)
153 bid->bip.bip_flags |= BIP_CHECK_GUARD;
154 if (bi->flags & BLK_INTEGRITY_REF_TAG)
155 bid->bip.bip_flags |= BIP_CHECK_REFTAG;
156 }
157
158 /* Auto-generate integrity metadata if this is a write */
159 if (bio_data_dir(bio) == WRITE && bip_should_check(&bid->bip))
160 blk_integrity_generate(bio);
161 else
162 bid->saved_bio_iter = bio->bi_iter;
163 return true;
164 }
165 EXPORT_SYMBOL(bio_integrity_prep);
166
blk_flush_integrity(void)167 void blk_flush_integrity(void)
168 {
169 flush_workqueue(kintegrityd_wq);
170 }
171
blk_integrity_auto_init(void)172 static int __init blk_integrity_auto_init(void)
173 {
174 bid_slab = kmem_cache_create("bio_integrity_data",
175 sizeof(struct bio_integrity_data), 0,
176 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
177
178 if (mempool_init_slab_pool(&bid_pool, BIO_POOL_SIZE, bid_slab))
179 panic("bio: can't create integrity pool\n");
180
181 /*
182 * kintegrityd won't block much but may burn a lot of CPU cycles.
183 * Make it highpri CPU intensive wq with max concurrency of 1.
184 */
185 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
186 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
187 if (!kintegrityd_wq)
188 panic("Failed to create kintegrityd\n");
189 return 0;
190 }
191 subsys_initcall(blk_integrity_auto_init);
192