/* * 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 = "none", .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. */ 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, (unsigned int *)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; } /* * If the data compressed only slightly, it is better to leave it * uncompressed to improve read speed. */ if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF) 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, (unsigned int *)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 ubifs_compressors_exit(void) { compr_exit(&lzo_compr); compr_exit(&zlib_compr); }