1 /*
2 * Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 */
13
14 #include <crypto/hash.h>
15 #include <linux/err.h>
16 #include "hash.h"
17
18 static struct crypto_shash *tfm;
19
btrfs_hash_init(void)20 int __init btrfs_hash_init(void)
21 {
22 tfm = crypto_alloc_shash("crc32c", 0, 0);
23
24 return PTR_ERR_OR_ZERO(tfm);
25 }
26
btrfs_hash_exit(void)27 void btrfs_hash_exit(void)
28 {
29 crypto_free_shash(tfm);
30 }
31
btrfs_crc32c(u32 crc,const void * address,unsigned int length)32 u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length)
33 {
34 SHASH_DESC_ON_STACK(shash, tfm);
35 u32 *ctx = (u32 *)shash_desc_ctx(shash);
36 u32 retval;
37 int err;
38
39 shash->tfm = tfm;
40 shash->flags = 0;
41 *ctx = crc;
42
43 err = crypto_shash_update(shash, address, length);
44 BUG_ON(err);
45
46 retval = *ctx;
47 barrier_data(ctx);
48 return retval;
49 }
50