path: root/lib/crc-t10dif.c (plain)
blob: 1ad33e555805a22cc901d4ed029826eea0b78250

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>
14	#include <linux/err.h>
15	#include <linux/init.h>
16	#include <crypto/hash.h>
17	#include <linux/static_key.h>
18
19	static struct crypto_shash *crct10dif_tfm;
20	static struct static_key crct10dif_fallback __read_mostly;
21
22	__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
23	{
24	struct {
25	struct shash_desc shash;
26	char ctx[2];
27	} desc;
28	int err;
29
30	if (static_key_false(&crct10dif_fallback))
31	return crc_t10dif_generic(crc, buffer, len);
32
33	desc.shash.tfm = crct10dif_tfm;
34	desc.shash.flags = 0;
35	*(__u16 *)desc.ctx = crc;
36
37	err = crypto_shash_update(&desc.shash, buffer, len);
38	BUG_ON(err);
39
40	return *(__u16 *)desc.ctx;
41	}
42	EXPORT_SYMBOL(crc_t10dif_update);
43
44	__u16 crc_t10dif(const unsigned char *buffer, size_t len)
45	{
46	return crc_t10dif_update(0, buffer, len);
47	}
48	EXPORT_SYMBOL(crc_t10dif);
49
50	static int __init crc_t10dif_mod_init(void)
51	{
52	crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
53	if (IS_ERR(crct10dif_tfm)) {
54	static_key_slow_inc(&crct10dif_fallback);
55	crct10dif_tfm = NULL;
56	}
57	return 0;
58	}
59
60	static void __exit crc_t10dif_mod_fini(void)
61	{
62	crypto_free_shash(crct10dif_tfm);
63	}
64
65	module_init(crc_t10dif_mod_init);
66	module_exit(crc_t10dif_mod_fini);
67
68	MODULE_DESCRIPTION("T10 DIF CRC calculation");
69	MODULE_LICENSE("GPL");
70	MODULE_SOFTDEP("pre: crct10dif");
71