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author | Ingo Molnar <mingo@elte.hu> | 2008-07-18 10:14:56 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-07-18 10:14:56 +0200 |
commit | 48ae74443403ab25876959e84785f61bf421ccef (patch) | |
tree | dd6d8277f2f0e691edf49a38ff9a804f9a1532d0 /fs/ubifs/compress.c | |
parent | 1b82c9666a6f637ccb3a86d0fbe23d0427076815 (diff) | |
parent | 5b664cb235e97afbf34db9c4d77f08ebd725335e (diff) | |
download | blackbird-op-linux-48ae74443403ab25876959e84785f61bf421ccef.tar.gz blackbird-op-linux-48ae74443403ab25876959e84785f61bf421ccef.zip |
Merge branch 'linus' into x86/step
Diffstat (limited to 'fs/ubifs/compress.c')
-rw-r--r-- | fs/ubifs/compress.c | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/fs/ubifs/compress.c b/fs/ubifs/compress.c new file mode 100644 index 000000000000..5bb51dac3c16 --- /dev/null +++ b/fs/ubifs/compress.c @@ -0,0 +1,253 @@ +/* + * 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); +} |