Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
16struct 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
24static struct kmem_cache *bid_slab;
25static mempool_t bid_pool;
26static struct workqueue_struct *kintegrityd_wq;
27
28static 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
36static 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)
48static bool bip_should_check(struct bio_integrity_payload *bip)
49{
50 return bip->bip_flags & BIP_CHECK_FLAGS;
51}
52
53static bool bi_offload_capable(struct blk_integrity *bi)
54{
55 switch (bi->csum_type) {
56 case BLK_INTEGRITY_CSUM_CRC64:
57 return bi->metadata_size == sizeof(struct crc64_pi_tuple);
58 case BLK_INTEGRITY_CSUM_CRC:
59 case BLK_INTEGRITY_CSUM_IP:
60 return bi->metadata_size == sizeof(struct t10_pi_tuple);
61 default:
62 pr_warn_once("%s: unknown integrity checksum type:%d\n",
63 __func__, bi->csum_type);
64 fallthrough;
65 case BLK_INTEGRITY_CSUM_NONE:
66 return false;
67 }
68}
69
70/**
71 * __bio_integrity_endio - Integrity I/O completion function
72 * @bio: Protected bio
73 *
74 * Normally I/O completion is done in interrupt context. However, verifying I/O
75 * integrity is a time-consuming task which must be run in process context.
76 *
77 * This function postpones completion accordingly.
78 */
79bool __bio_integrity_endio(struct bio *bio)
80{
81 struct bio_integrity_payload *bip = bio_integrity(bio);
82 struct bio_integrity_data *bid =
83 container_of(bip, struct bio_integrity_data, bip);
84
85 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
86 bip_should_check(bip)) {
87 INIT_WORK(&bid->work, bio_integrity_verify_fn);
88 queue_work(kintegrityd_wq, &bid->work);
89 return false;
90 }
91
92 bio_integrity_finish(bid);
93 return true;
94}
95
96/**
97 * bio_integrity_prep - Prepare bio for integrity I/O
98 * @bio: bio to prepare
99 *
100 * Checks if the bio already has an integrity payload attached. If it does, the
101 * payload has been generated by another kernel subsystem, and we just pass it
102 * through.
103 * Otherwise allocates integrity payload and for writes the integrity metadata
104 * will be generated. For reads, the completion handler will verify the
105 * metadata.
106 */
107bool bio_integrity_prep(struct bio *bio)
108{
109 struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
110 struct bio_integrity_data *bid;
111 bool set_flags = true;
112 gfp_t gfp = GFP_NOIO;
113
114 if (!bi)
115 return true;
116
117 if (!bio_sectors(bio))
118 return true;
119
120 /* Already protected? */
121 if (bio_integrity(bio))
122 return true;
123
124 switch (bio_op(bio)) {
125 case REQ_OP_READ:
126 if (bi->flags & BLK_INTEGRITY_NOVERIFY) {
127 if (bi_offload_capable(bi))
128 return true;
129 set_flags = false;
130 }
131 break;
132 case REQ_OP_WRITE:
133 /*
134 * Zero the memory allocated to not leak uninitialized kernel
135 * memory to disk for non-integrity metadata where nothing else
136 * initializes the memory.
137 */
138 if (bi->flags & BLK_INTEGRITY_NOGENERATE) {
139 if (bi_offload_capable(bi))
140 return true;
141 set_flags = false;
142 gfp |= __GFP_ZERO;
143 } else if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE)
144 gfp |= __GFP_ZERO;
145 break;
146 default:
147 return true;
148 }
149
150 if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
151 return true;
152
153 bid = mempool_alloc(&bid_pool, GFP_NOIO);
154 bio_integrity_init(bio, &bid->bip, &bid->bvec, 1);
155 bid->bio = bio;
156 bid->bip.bip_flags |= BIP_BLOCK_INTEGRITY;
157 bio_integrity_alloc_buf(bio, gfp & __GFP_ZERO);
158
159 bip_set_seed(&bid->bip, bio->bi_iter.bi_sector);
160
161 if (set_flags) {
162 if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
163 bid->bip.bip_flags |= BIP_IP_CHECKSUM;
164 if (bi->csum_type)
165 bid->bip.bip_flags |= BIP_CHECK_GUARD;
166 if (bi->flags & BLK_INTEGRITY_REF_TAG)
167 bid->bip.bip_flags |= BIP_CHECK_REFTAG;
168 }
169
170 /* Auto-generate integrity metadata if this is a write */
171 if (bio_data_dir(bio) == WRITE && bip_should_check(&bid->bip))
172 blk_integrity_generate(bio);
173 else
174 bid->saved_bio_iter = bio->bi_iter;
175 return true;
176}
177EXPORT_SYMBOL(bio_integrity_prep);
178
179void blk_flush_integrity(void)
180{
181 flush_workqueue(kintegrityd_wq);
182}
183
184static int __init blk_integrity_auto_init(void)
185{
186 bid_slab = kmem_cache_create("bio_integrity_data",
187 sizeof(struct bio_integrity_data), 0,
188 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
189
190 if (mempool_init_slab_pool(&bid_pool, BIO_POOL_SIZE, bid_slab))
191 panic("bio: can't create integrity pool\n");
192
193 /*
194 * kintegrityd won't block much but may burn a lot of CPU cycles.
195 * Make it highpri CPU intensive wq with max concurrency of 1.
196 */
197 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
198 WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
199 if (!kintegrityd_wq)
200 panic("Failed to create kintegrityd\n");
201 return 0;
202}
203subsys_initcall(blk_integrity_auto_init);