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
crc_t10dif_update(__u16 crc,const unsigned char * buffer,size_t len)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
crc_t10dif(const unsigned char * buffer,size_t len)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
crc_t10dif_mod_init(void)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
crc_t10dif_mod_fini(void)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