linux-sg2042/fs/btrfs/hash.c

51 lines
1.1 KiB
C

/*
* Copyright (C) 2014 Filipe David Borba Manana <fdmanana@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <crypto/hash.h>
#include <linux/err.h>
#include "hash.h"
static struct crypto_shash *tfm;
int __init btrfs_hash_init(void)
{
tfm = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(tfm))
return PTR_ERR(tfm);
return 0;
}
void btrfs_hash_exit(void)
{
crypto_free_shash(tfm);
}
u32 btrfs_crc32c(u32 crc, const void *address, unsigned int length)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(tfm)];
} desc;
int err;
desc.shash.tfm = tfm;
desc.shash.flags = 0;
*(u32 *)desc.ctx = crc;
err = crypto_shash_update(&desc.shash, address, length);
BUG_ON(err);
return *(u32 *)desc.ctx;
}