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linux-next/lib/crc-t10dif.c
Akinobu Mita 10081fb532 lib: introduce crc_t10dif_update()
This introduces crc_t10dif_update() which enables to calculate CRC
for a block which straddles multiple SG elements by calling multiple
times.  This also converts crc_t10dif() to use crc_t10dif_update() as
they are almost same.

(remove extra function call in crc_t10dif() and crc_t10dif_update -
 Tim + Herbert)

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: target-devel@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-05-30 22:42:24 -07:00

71 lines
1.6 KiB
C

/*
* 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_update(__u16 crc, 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(crc, buffer, len);
desc.shash.tfm = crct10dif_tfm;
desc.shash.flags = 0;
*(__u16 *)desc.ctx = crc;
err = crypto_shash_update(&desc.shash, buffer, len);
BUG_ON(err);
return *(__u16 *)desc.ctx;
}
EXPORT_SYMBOL(crc_t10dif_update);
__u16 crc_t10dif(const unsigned char *buffer, size_t len)
{
return crc_t10dif_update(0, buffer, len);
}
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");