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