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DEFINITIONS
This source file includes following definitions.
- ubifs_compress
- ubifs_decompress
- compr_init
- compr_exit
- ubifs_compressors_init
- ubifs_compressors_exit
/*
* This file is part of UBIFS.
*
* Copyright (C) 2006-2008 Nokia Corporation.
* Copyright (C) 2006, 2007 University of Szeged, Hungary
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 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.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Authors: Adrian Hunter
* Artem Bityutskiy (Битюцкий Артём)
* Zoltan Sogor
*/
/*
* This file provides a single place to access to compression and
* decompression.
*/
#include <linux/crypto.h>
#include "ubifs.h"
/* Fake description object for the "none" compressor */
static struct ubifs_compressor none_compr = {
.compr_type = UBIFS_COMPR_NONE,
.name = "no compression",
.capi_name = "",
};
#ifdef CONFIG_UBIFS_FS_LZO
static DEFINE_MUTEX(lzo_mutex);
static struct ubifs_compressor lzo_compr = {
.compr_type = UBIFS_COMPR_LZO,
.comp_mutex = &lzo_mutex,
.name = "LZO",
.capi_name = "lzo",
};
#else
static struct ubifs_compressor lzo_compr = {
.compr_type = UBIFS_COMPR_LZO,
.name = "LZO",
};
#endif
#ifdef CONFIG_UBIFS_FS_ZLIB
static DEFINE_MUTEX(deflate_mutex);
static DEFINE_MUTEX(inflate_mutex);
static struct ubifs_compressor zlib_compr = {
.compr_type = UBIFS_COMPR_ZLIB,
.comp_mutex = &deflate_mutex,
.decomp_mutex = &inflate_mutex,
.name = "zlib",
.capi_name = "deflate",
};
#else
static struct ubifs_compressor zlib_compr = {
.compr_type = UBIFS_COMPR_ZLIB,
.name = "zlib",
};
#endif
/* All UBIFS compressors */
struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
/**
* ubifs_compress - compress data.
* @in_buf: data to compress
* @in_len: length of the data to compress
* @out_buf: output buffer where compressed data should be stored
* @out_len: output buffer length is returned here
* @compr_type: type of compression to use on enter, actually used compression
* type on exit
*
* This function compresses input buffer @in_buf of length @in_len and stores
* the result in the output buffer @out_buf and the resulting length in
* @out_len. If the input buffer does not compress, it is just copied to the
* @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
* compression error occurred.
*
* Note, if the input buffer was not compressed, it is copied to the output
* buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
*
* This functions returns %0 on success or a negative error code on failure.
*/
void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len,
int *compr_type)
{
int err;
struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
if (*compr_type == UBIFS_COMPR_NONE)
goto no_compr;
/* If the input data is small, do not even try to compress it */
if (in_len < UBIFS_MIN_COMPR_LEN)
goto no_compr;
if (compr->comp_mutex)
mutex_lock(compr->comp_mutex);
err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
out_len);
if (compr->comp_mutex)
mutex_unlock(compr->comp_mutex);
if (unlikely(err)) {
ubifs_warn("cannot compress %d bytes, compressor %s, "
"error %d, leave data uncompressed",
in_len, compr->name, err);
goto no_compr;
}
/*
* Presently, we just require that compression results in less data,
* rather than any defined minimum compression ratio or amount.
*/
if (ALIGN(*out_len, 8) >= ALIGN(in_len, 8))
goto no_compr;
return;
no_compr:
memcpy(out_buf, in_buf, in_len);
*out_len = in_len;
*compr_type = UBIFS_COMPR_NONE;
}
/**
* ubifs_decompress - decompress data.
* @in_buf: data to decompress
* @in_len: length of the data to decompress
* @out_buf: output buffer where decompressed data should
* @out_len: output length is returned here
* @compr_type: type of compression
*
* This function decompresses data from buffer @in_buf into buffer @out_buf.
* The length of the uncompressed data is returned in @out_len. This functions
* returns %0 on success or a negative error code on failure.
*/
int ubifs_decompress(const void *in_buf, int in_len, void *out_buf,
int *out_len, int compr_type)
{
int err;
struct ubifs_compressor *compr;
if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
ubifs_err("invalid compression type %d", compr_type);
return -EINVAL;
}
compr = ubifs_compressors[compr_type];
if (unlikely(!compr->capi_name)) {
ubifs_err("%s compression is not compiled in", compr->name);
return -EINVAL;
}
if (compr_type == UBIFS_COMPR_NONE) {
memcpy(out_buf, in_buf, in_len);
*out_len = in_len;
return 0;
}
if (compr->decomp_mutex)
mutex_lock(compr->decomp_mutex);
err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
out_len);
if (compr->decomp_mutex)
mutex_unlock(compr->decomp_mutex);
if (err)
ubifs_err("cannot decompress %d bytes, compressor %s, "
"error %d", in_len, compr->name, err);
return err;
}
/**
* compr_init - initialize a compressor.
* @compr: compressor description object
*
* This function initializes the requested compressor and returns zero in case
* of success or a negative error code in case of failure.
*/
static int __init compr_init(struct ubifs_compressor *compr)
{
if (compr->capi_name) {
compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
if (IS_ERR(compr->cc)) {
ubifs_err("cannot initialize compressor %s, error %ld",
compr->name, PTR_ERR(compr->cc));
return PTR_ERR(compr->cc);
}
}
ubifs_compressors[compr->compr_type] = compr;
return 0;
}
/**
* compr_exit - de-initialize a compressor.
* @compr: compressor description object
*/
static void compr_exit(struct ubifs_compressor *compr)
{
if (compr->capi_name)
crypto_free_comp(compr->cc);
return;
}
/**
* ubifs_compressors_init - initialize UBIFS compressors.
*
* This function initializes the compressor which were compiled in. Returns
* zero in case of success and a negative error code in case of failure.
*/
int __init ubifs_compressors_init(void)
{
int err;
err = compr_init(&lzo_compr);
if (err)
return err;
err = compr_init(&zlib_compr);
if (err)
goto out_lzo;
ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
return 0;
out_lzo:
compr_exit(&lzo_compr);
return err;
}
/**
* ubifs_compressors_exit - de-initialize UBIFS compressors.
*/
void __exit ubifs_compressors_exit(void)
{
compr_exit(&lzo_compr);
compr_exit(&zlib_compr);
}