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40b0b3f8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f11f594e MP |
2 | /* |
3 | * T10 Data Integrity Field CRC16 calculation | |
4 | * | |
5 | * Copyright (c) 2007 Oracle Corporation. All rights reserved. | |
6 | * Written by Martin K. Petersen <martin.petersen@oracle.com> | |
f11f594e MP |
7 | */ |
8 | ||
9 | #include <linux/types.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/crc-t10dif.h> | |
68411521 HX |
12 | #include <linux/err.h> |
13 | #include <linux/init.h> | |
14 | #include <crypto/hash.h> | |
b7637754 | 15 | #include <crypto/algapi.h> |
26052f9b | 16 | #include <linux/static_key.h> |
b7637754 | 17 | #include <linux/notifier.h> |
f11f594e | 18 | |
b7637754 | 19 | static struct crypto_shash __rcu *crct10dif_tfm; |
be924e0a | 20 | static DEFINE_STATIC_KEY_TRUE(crct10dif_fallback); |
a7e7edfe | 21 | static DEFINE_MUTEX(crc_t10dif_mutex); |
3906f640 | 22 | static struct work_struct crct10dif_rehash_work; |
b7637754 | 23 | |
3906f640 | 24 | static int crc_t10dif_notify(struct notifier_block *self, unsigned long val, void *data) |
b7637754 MP |
25 | { |
26 | struct crypto_alg *alg = data; | |
b7637754 MP |
27 | |
28 | if (val != CRYPTO_MSG_ALG_LOADED || | |
b7637754 MP |
29 | strncmp(alg->cra_name, CRC_T10DIF_STRING, strlen(CRC_T10DIF_STRING))) |
30 | return 0; | |
31 | ||
3906f640 HX |
32 | schedule_work(&crct10dif_rehash_work); |
33 | return 0; | |
34 | } | |
35 | ||
36 | static void crc_t10dif_rehash(struct work_struct *work) | |
37 | { | |
38 | struct crypto_shash *new, *old; | |
39 | ||
b7637754 MP |
40 | mutex_lock(&crc_t10dif_mutex); |
41 | old = rcu_dereference_protected(crct10dif_tfm, | |
42 | lockdep_is_held(&crc_t10dif_mutex)); | |
b7637754 MP |
43 | new = crypto_alloc_shash("crct10dif", 0, 0); |
44 | if (IS_ERR(new)) { | |
45 | mutex_unlock(&crc_t10dif_mutex); | |
3906f640 | 46 | return; |
b7637754 MP |
47 | } |
48 | rcu_assign_pointer(crct10dif_tfm, new); | |
49 | mutex_unlock(&crc_t10dif_mutex); | |
50 | ||
be924e0a EB |
51 | if (old) { |
52 | synchronize_rcu(); | |
53 | crypto_free_shash(old); | |
54 | } else { | |
55 | static_branch_disable(&crct10dif_fallback); | |
56 | } | |
b7637754 MP |
57 | } |
58 | ||
59 | static struct notifier_block crc_t10dif_nb = { | |
3906f640 | 60 | .notifier_call = crc_t10dif_notify, |
b7637754 | 61 | }; |
f11f594e | 62 | |
10081fb5 | 63 | __u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len) |
f11f594e | 64 | { |
68411521 HX |
65 | struct { |
66 | struct shash_desc shash; | |
67 | char ctx[2]; | |
68 | } desc; | |
69 | int err; | |
70 | ||
be924e0a | 71 | if (static_branch_unlikely(&crct10dif_fallback)) |
10081fb5 | 72 | return crc_t10dif_generic(crc, buffer, len); |
26052f9b | 73 | |
b7637754 MP |
74 | rcu_read_lock(); |
75 | desc.shash.tfm = rcu_dereference(crct10dif_tfm); | |
10081fb5 | 76 | *(__u16 *)desc.ctx = crc; |
f11f594e | 77 | |
68411521 | 78 | err = crypto_shash_update(&desc.shash, buffer, len); |
b7637754 MP |
79 | rcu_read_unlock(); |
80 | ||
68411521 | 81 | BUG_ON(err); |
f11f594e | 82 | |
68411521 | 83 | return *(__u16 *)desc.ctx; |
f11f594e | 84 | } |
10081fb5 AM |
85 | EXPORT_SYMBOL(crc_t10dif_update); |
86 | ||
87 | __u16 crc_t10dif(const unsigned char *buffer, size_t len) | |
88 | { | |
89 | return crc_t10dif_update(0, buffer, len); | |
90 | } | |
f11f594e MP |
91 | EXPORT_SYMBOL(crc_t10dif); |
92 | ||
68411521 HX |
93 | static int __init crc_t10dif_mod_init(void) |
94 | { | |
3906f640 | 95 | INIT_WORK(&crct10dif_rehash_work, crc_t10dif_rehash); |
b7637754 | 96 | crypto_register_notifier(&crc_t10dif_nb); |
be924e0a | 97 | crc_t10dif_rehash(&crct10dif_rehash_work); |
26052f9b | 98 | return 0; |
68411521 HX |
99 | } |
100 | ||
101 | static void __exit crc_t10dif_mod_fini(void) | |
102 | { | |
b7637754 | 103 | crypto_unregister_notifier(&crc_t10dif_nb); |
3906f640 HX |
104 | cancel_work_sync(&crct10dif_rehash_work); |
105 | crypto_free_shash(rcu_dereference_protected(crct10dif_tfm, 1)); | |
68411521 HX |
106 | } |
107 | ||
108 | module_init(crc_t10dif_mod_init); | |
109 | module_exit(crc_t10dif_mod_fini); | |
110 | ||
11dcb103 MP |
111 | static int crc_t10dif_transform_show(char *buffer, const struct kernel_param *kp) |
112 | { | |
3906f640 HX |
113 | struct crypto_shash *tfm; |
114 | const char *name; | |
115 | int len; | |
116 | ||
be924e0a | 117 | if (static_branch_unlikely(&crct10dif_fallback)) |
11dcb103 MP |
118 | return sprintf(buffer, "fallback\n"); |
119 | ||
3906f640 HX |
120 | rcu_read_lock(); |
121 | tfm = rcu_dereference(crct10dif_tfm); | |
3906f640 HX |
122 | name = crypto_tfm_alg_driver_name(crypto_shash_tfm(tfm)); |
123 | len = sprintf(buffer, "%s\n", name); | |
3906f640 HX |
124 | rcu_read_unlock(); |
125 | ||
126 | return len; | |
11dcb103 MP |
127 | } |
128 | ||
129 | module_param_call(transform, NULL, crc_t10dif_transform_show, NULL, 0644); | |
130 | ||
f11f594e MP |
131 | MODULE_DESCRIPTION("T10 DIF CRC calculation"); |
132 | MODULE_LICENSE("GPL"); | |
68411521 | 133 | MODULE_SOFTDEP("pre: crct10dif"); |