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 bio->bi_status = bio_integrity_verify(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
53 /**
54 * __bio_integrity_endio - Integrity I/O completion function
55 * @bio: Protected bio
56 *
57 * Normally I/O completion is done in interrupt context. However, verifying I/O
58 * integrity is a time-consuming task which must be run in process context.
59 *
60 * This function postpones completion accordingly.
61 */
__bio_integrity_endio(struct bio * bio)62 bool __bio_integrity_endio(struct bio *bio)
63 {
64 struct bio_integrity_payload *bip = bio_integrity(bio);
65 struct bio_integrity_data *bid =
66 container_of(bip, struct bio_integrity_data, bip);
67
68 if (bio_op(bio) == REQ_OP_READ && !bio->bi_status &&
69 bip_should_check(bip)) {
70 INIT_WORK(&bid->work, bio_integrity_verify_fn);
71 queue_work(kintegrityd_wq, &bid->work);
72 return false;
73 }
74
75 bio_integrity_finish(bid);
76 return true;
77 }
78
79 /**
80 * bio_integrity_prep - Prepare bio for integrity I/O
81 * @bio: bio to prepare
82 * @action: preparation action needed (BI_ACT_*)
83 *
84 * Allocate the integrity payload. For writes, generate the integrity metadata
85 * and for reads, setup the completion handler to verify the metadata.
86 *
87 * This is used for bios that do not have user integrity payloads attached.
88 */
bio_integrity_prep(struct bio * bio,unsigned int action)89 void bio_integrity_prep(struct bio *bio, unsigned int action)
90 {
91 struct bio_integrity_data *bid;
92
93 bid = mempool_alloc(&bid_pool, GFP_NOIO);
94 bio_integrity_init(bio, &bid->bip, &bid->bvec, 1);
95 bid->bio = bio;
96 bid->bip.bip_flags |= BIP_BLOCK_INTEGRITY;
97 bio_integrity_alloc_buf(bio, action & BI_ACT_ZERO);
98 if (action & BI_ACT_CHECK)
99 bio_integrity_setup_default(bio);
100
101 /* Auto-generate integrity metadata if this is a write */
102 if (bio_data_dir(bio) == WRITE && bip_should_check(&bid->bip))
103 bio_integrity_generate(bio);
104 else
105 bid->saved_bio_iter = bio->bi_iter;
106 }
107 EXPORT_SYMBOL(bio_integrity_prep);
108
blk_flush_integrity(void)109 void blk_flush_integrity(void)
110 {
111 flush_workqueue(kintegrityd_wq);
112 }
113
blk_integrity_auto_init(void)114 static int __init blk_integrity_auto_init(void)
115 {
116 bid_slab = kmem_cache_create("bio_integrity_data",
117 sizeof(struct bio_integrity_data), 0,
118 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
119
120 if (mempool_init_slab_pool(&bid_pool, BIO_POOL_SIZE, bid_slab))
121 panic("bio: can't create integrity pool\n");
122
123 /*
124 * kintegrityd won't block much but may burn a lot of CPU cycles.
125 * Make it highpri CPU intensive wq with max concurrency of 1.
126 */
127 kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
128 WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_PERCPU, 1);
129 if (!kintegrityd_wq)
130 panic("Failed to create kintegrityd\n");
131 return 0;
132 }
133 subsys_initcall(blk_integrity_auto_init);
134