lib/crc-t10dif.c

   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
  18 static struct crypto_shash *crct10dif_tfm;
  19
  20 __u16 crc_t10dif(const unsigned char *buffer, size_t len)
  21 {
  22         struct {
  23                 struct shash_desc shash;
  24                 char ctx[2];
  25         } desc;
  26         int err;
  27
  28         desc.shash.tfm = crct10dif_tfm;
  29         desc.shash.flags = 0;
  30         *(__u16 *)desc.ctx = 0;
  31
  32         err = crypto_shash_update(&desc.shash, buffer, len);
  33         BUG_ON(err);
  34
  35         return *(__u16 *)desc.ctx;
  36 }
  37 EXPORT_SYMBOL(crc_t10dif);
  38
  39 static int __init crc_t10dif_mod_init(void)
  40 {
  41         crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
  42         return PTR_RET(crct10dif_tfm);
  43 }
  44
  45 static void __exit crc_t10dif_mod_fini(void)
  46 {
  47         crypto_free_shash(crct10dif_tfm);
  48 }
  49
  50 module_init(crc_t10dif_mod_init);
  51 module_exit(crc_t10dif_mod_fini);
  52
  53 MODULE_DESCRIPTION("T10 DIF CRC calculation");
  54 MODULE_LICENSE("GPL");
  55 MODULE_SOFTDEP("pre: crct10dif");