File: compress.c

package info (click to toggle)
linux 3.16.7-ckt2-1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 734,120 kB
  • ctags: 2,369,605
  • sloc: ansic: 12,212,866; asm: 277,256; perl: 53,999; xml: 47,771; makefile: 30,481; sh: 8,035; python: 6,583; cpp: 5,121; yacc: 4,254; lex: 2,215; awk: 741; pascal: 231; lisp: 218; sed: 30
file content (250 lines) | stat: -rw-r--r-- 6,760 bytes parent folder | download | duplicates (15)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
/*
 * 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);
}