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
18static struct crypto_shash *tfm;
19
20int __init btrfs_hash_init(void)
21{
22	tfm = crypto_alloc_shash("crc32c", 0, 0);
23	if (IS_ERR(tfm))
24		return PTR_ERR(tfm);
25
26	return 0;
27}
28
29void btrfs_hash_exit(void)
30{
31	crypto_free_shash(tfm);
32}
33
34u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length)
35{
36	struct {
37		struct shash_desc shash;
38		char ctx[crypto_shash_descsize(tfm)];
39	} desc;
40	int err;
41
42	desc.shash.tfm = tfm;
43	desc.shash.flags = 0;
44	*(u32 *)desc.ctx = crc;
45
46	err = crypto_shash_update(&desc.shash, address, length);
47	BUG_ON(err);
48
49	return *(u32 *)desc.ctx;
50}