crc-t10dif.c
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/*
* T10 Data Integrity Field CRC16 calculation
*
* Copyright (c) 2007 Oracle Corporation. All rights reserved.
* Written by Martin K. Petersen <martin.petersen@oracle.com>
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
#include <linux/types.h>
#include <linux/module.h>
#include <linux/crc-t10dif.h>
#include <linux/err.h>
#include <linux/init.h>
#include <crypto/hash.h>
#include <linux/static_key.h>
static struct crypto_shash *crct10dif_tfm;
static struct static_key crct10dif_fallback __read_mostly;
__u16 crc_t10dif(const unsigned char *buffer, size_t len)
{
struct {
struct shash_desc shash;
char ctx[2];
} desc;
int err;
if (static_key_false(&crct10dif_fallback))
return crc_t10dif_generic(0, buffer, len);
desc.shash.tfm = crct10dif_tfm;
desc.shash.flags = 0;
*(__u16 *)desc.ctx = 0;
err = crypto_shash_update(&desc.shash, buffer, len);
BUG_ON(err);
return *(__u16 *)desc.ctx;
}
EXPORT_SYMBOL(crc_t10dif);
static int __init crc_t10dif_mod_init(void)
{
crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
if (IS_ERR(crct10dif_tfm)) {
static_key_slow_inc(&crct10dif_fallback);
crct10dif_tfm = NULL;
}
return 0;
}
static void __exit crc_t10dif_mod_fini(void)
{
crypto_free_shash(crct10dif_tfm);
}
module_init(crc_t10dif_mod_init);
module_exit(crc_t10dif_mod_fini);
MODULE_DESCRIPTION("T10 DIF CRC calculation");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crct10dif");