blob: dfe6ec17c0a5fa774ec34d23de696be7b99a6182 [file] [log] [blame]
Martin K. Petersenf11f5942008-06-25 11:22:42 -04001/*
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>
Herbert Xu684115212013-09-07 12:56:26 +100014#include <linux/err.h>
15#include <linux/init.h>
16#include <crypto/hash.h>
Herbert Xu26052f92013-09-12 15:31:34 +100017#include <linux/static_key.h>
Martin K. Petersenf11f5942008-06-25 11:22:42 -040018
Herbert Xu684115212013-09-07 12:56:26 +100019static struct crypto_shash *crct10dif_tfm;
Herbert Xu26052f92013-09-12 15:31:34 +100020static struct static_key crct10dif_fallback __read_mostly;
Martin K. Petersenf11f5942008-06-25 11:22:42 -040021
22__u16 crc_t10dif(const unsigned char *buffer, size_t len)
23{
Herbert Xu684115212013-09-07 12:56:26 +100024 struct {
25 struct shash_desc shash;
26 char ctx[2];
27 } desc;
28 int err;
Martin K. Petersenf11f5942008-06-25 11:22:42 -040029
Herbert Xu26052f92013-09-12 15:31:34 +100030 if (static_key_false(&crct10dif_fallback))
31 return crc_t10dif_generic(0, buffer, len);
32
Herbert Xu684115212013-09-07 12:56:26 +100033 desc.shash.tfm = crct10dif_tfm;
34 desc.shash.flags = 0;
35 *(__u16 *)desc.ctx = 0;
Martin K. Petersenf11f5942008-06-25 11:22:42 -040036
Herbert Xu684115212013-09-07 12:56:26 +100037 err = crypto_shash_update(&desc.shash, buffer, len);
38 BUG_ON(err);
39
40 return *(__u16 *)desc.ctx;
Martin K. Petersenf11f5942008-06-25 11:22:42 -040041}
42EXPORT_SYMBOL(crc_t10dif);
43
Herbert Xu684115212013-09-07 12:56:26 +100044static int __init crc_t10dif_mod_init(void)
45{
46 crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
Herbert Xu26052f92013-09-12 15:31:34 +100047 if (IS_ERR(crct10dif_tfm)) {
48 static_key_slow_inc(&crct10dif_fallback);
49 crct10dif_tfm = NULL;
50 }
51 return 0;
Herbert Xu684115212013-09-07 12:56:26 +100052}
53
54static void __exit crc_t10dif_mod_fini(void)
55{
56 crypto_free_shash(crct10dif_tfm);
57}
58
59module_init(crc_t10dif_mod_init);
60module_exit(crc_t10dif_mod_fini);
61
Martin K. Petersenf11f5942008-06-25 11:22:42 -040062MODULE_DESCRIPTION("T10 DIF CRC calculation");
63MODULE_LICENSE("GPL");
Herbert Xu684115212013-09-07 12:56:26 +100064MODULE_SOFTDEP("pre: crct10dif");