linux/fs/ubifs/compress.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 * Copyright (C) 2006, 2007 University of Szeged, Hungary
 *
 * 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 = …;

#ifdef CONFIG_UBIFS_FS_LZO
static DEFINE_MUTEX(lzo_mutex);

static struct ubifs_compressor lzo_compr = …;
#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 = …;
#else
static struct ubifs_compressor zlib_compr = {
	.compr_type = UBIFS_COMPR_ZLIB,
	.name = "zlib",
};
#endif

#ifdef CONFIG_UBIFS_FS_ZSTD
static DEFINE_MUTEX(zstd_enc_mutex);
static DEFINE_MUTEX(zstd_dec_mutex);

static struct ubifs_compressor zstd_compr = …;
#else
static struct ubifs_compressor zstd_compr = {
	.compr_type = UBIFS_COMPR_ZSTD,
	.name = "zstd",
};
#endif

/* All UBIFS compressors */
struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];

/**
 * ubifs_compress - compress data.
 * @c: UBIFS file-system description object
 * @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.
 */
void ubifs_compress(const struct ubifs_info *c, const void *in_buf,
		    int in_len, void *out_buf, int *out_len, int *compr_type)
{ … }

/**
 * ubifs_decompress - decompress data.
 * @c: UBIFS file-system description object
 * @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 struct ubifs_info *c, const void *in_buf,
		     int in_len, void *out_buf, int *out_len, int compr_type)
{ … }

/**
 * 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)
{ … }

/**
 * compr_exit - de-initialize a compressor.
 * @compr: compressor description object
 */
static void compr_exit(struct ubifs_compressor *compr)
{ … }

/**
 * 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)
{ … }

/**
 * ubifs_compressors_exit - de-initialize UBIFS compressors.
 */
void ubifs_compressors_exit(void)
{ … }