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1 | /* |
2 | * This file is part of UBIFS. |
3 | * |
4 | * Copyright (C) 2006-2008 Nokia Corporation. |
5 | * Copyright (C) 2006, 2007 University of Szeged, Hungary |
6 | * |
7 | * This program is free software; you can redistribute it and/or modify it |
8 | * under the terms of the GNU General Public License version 2 as published by |
9 | * the Free Software Foundation. |
10 | * |
11 | * This program is distributed in the hope that it will be useful, but WITHOUT |
12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
14 | * more details. |
15 | * |
16 | * You should have received a copy of the GNU General Public License along with |
17 | * this program; if not, write to the Free Software Foundation, Inc., 51 |
18 | * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
19 | * |
20 | * Authors: Adrian Hunter |
21 | * Artem Bityutskiy (Битюцкий Артём) |
22 | * Zoltan Sogor |
23 | */ |
24 | |
25 | /* |
26 | * This file provides a single place to access to compression and |
27 | * decompression. |
28 | */ |
29 | |
30 | #include <linux/crypto.h> |
31 | #include "ubifs.h" |
32 | |
33 | /* Fake description object for the "none" compressor */ |
34 | static struct ubifs_compressor none_compr = { |
35 | .compr_type = UBIFS_COMPR_NONE, |
36 | .name = "none", |
37 | .capi_name = "", |
38 | }; |
39 | |
40 | #ifdef CONFIG_UBIFS_FS_LZO |
41 | static DEFINE_MUTEX(lzo_mutex); |
42 | |
43 | static struct ubifs_compressor lzo_compr = { |
44 | .compr_type = UBIFS_COMPR_LZO, |
45 | .comp_mutex = &lzo_mutex, |
46 | .name = "lzo", |
47 | .capi_name = "lzo", |
48 | }; |
49 | #else |
50 | static struct ubifs_compressor lzo_compr = { |
51 | .compr_type = UBIFS_COMPR_LZO, |
52 | .name = "lzo", |
53 | }; |
54 | #endif |
55 | |
56 | #ifdef CONFIG_UBIFS_FS_ZLIB |
57 | static DEFINE_MUTEX(deflate_mutex); |
58 | static DEFINE_MUTEX(inflate_mutex); |
59 | |
60 | static struct ubifs_compressor zlib_compr = { |
61 | .compr_type = UBIFS_COMPR_ZLIB, |
62 | .comp_mutex = &deflate_mutex, |
63 | .decomp_mutex = &inflate_mutex, |
64 | .name = "zlib", |
65 | .capi_name = "deflate", |
66 | }; |
67 | #else |
68 | static struct ubifs_compressor zlib_compr = { |
69 | .compr_type = UBIFS_COMPR_ZLIB, |
70 | .name = "zlib", |
71 | }; |
72 | #endif |
73 | |
74 | /* All UBIFS compressors */ |
75 | struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT]; |
76 | |
77 | /** |
78 | * ubifs_compress - compress data. |
79 | * @in_buf: data to compress |
80 | * @in_len: length of the data to compress |
81 | * @out_buf: output buffer where compressed data should be stored |
82 | * @out_len: output buffer length is returned here |
83 | * @compr_type: type of compression to use on enter, actually used compression |
84 | * type on exit |
85 | * |
86 | * This function compresses input buffer @in_buf of length @in_len and stores |
87 | * the result in the output buffer @out_buf and the resulting length in |
88 | * @out_len. If the input buffer does not compress, it is just copied to the |
89 | * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if |
90 | * compression error occurred. |
91 | * |
92 | * Note, if the input buffer was not compressed, it is copied to the output |
93 | * buffer and %UBIFS_COMPR_NONE is returned in @compr_type. |
94 | */ |
95 | void ubifs_compress(const void *in_buf, int in_len, void *out_buf, int *out_len, |
96 | int *compr_type) |
97 | { |
98 | int err; |
99 | struct ubifs_compressor *compr = ubifs_compressors[*compr_type]; |
100 | |
101 | if (*compr_type == UBIFS_COMPR_NONE) |
102 | goto no_compr; |
103 | |
104 | /* If the input data is small, do not even try to compress it */ |
105 | if (in_len < UBIFS_MIN_COMPR_LEN) |
106 | goto no_compr; |
107 | |
108 | if (compr->comp_mutex) |
109 | mutex_lock(compr->comp_mutex); |
110 | err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf, |
111 | (unsigned int *)out_len); |
112 | if (compr->comp_mutex) |
113 | mutex_unlock(compr->comp_mutex); |
114 | if (unlikely(err)) { |
115 | ubifs_warn("cannot compress %d bytes, compressor %s, " |
116 | "error %d, leave data uncompressed", |
117 | in_len, compr->name, err); |
118 | goto no_compr; |
119 | } |
120 | |
121 | /* |
122 | * If the data compressed only slightly, it is better to leave it |
123 | * uncompressed to improve read speed. |
124 | */ |
125 | if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF) |
126 | goto no_compr; |
127 | |
128 | return; |
129 | |
130 | no_compr: |
131 | memcpy(out_buf, in_buf, in_len); |
132 | *out_len = in_len; |
133 | *compr_type = UBIFS_COMPR_NONE; |
134 | } |
135 | |
136 | /** |
137 | * ubifs_decompress - decompress data. |
138 | * @in_buf: data to decompress |
139 | * @in_len: length of the data to decompress |
140 | * @out_buf: output buffer where decompressed data should |
141 | * @out_len: output length is returned here |
142 | * @compr_type: type of compression |
143 | * |
144 | * This function decompresses data from buffer @in_buf into buffer @out_buf. |
145 | * The length of the uncompressed data is returned in @out_len. This functions |
146 | * returns %0 on success or a negative error code on failure. |
147 | */ |
148 | int ubifs_decompress(const void *in_buf, int in_len, void *out_buf, |
149 | int *out_len, int compr_type) |
150 | { |
151 | int err; |
152 | struct ubifs_compressor *compr; |
153 | |
154 | if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) { |
155 | ubifs_err("invalid compression type %d", compr_type); |
156 | return -EINVAL; |
157 | } |
158 | |
159 | compr = ubifs_compressors[compr_type]; |
160 | |
161 | if (unlikely(!compr->capi_name)) { |
162 | ubifs_err("%s compression is not compiled in", compr->name); |
163 | return -EINVAL; |
164 | } |
165 | |
166 | if (compr_type == UBIFS_COMPR_NONE) { |
167 | memcpy(out_buf, in_buf, in_len); |
168 | *out_len = in_len; |
169 | return 0; |
170 | } |
171 | |
172 | if (compr->decomp_mutex) |
173 | mutex_lock(compr->decomp_mutex); |
174 | err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf, |
175 | (unsigned int *)out_len); |
176 | if (compr->decomp_mutex) |
177 | mutex_unlock(compr->decomp_mutex); |
178 | if (err) |
179 | ubifs_err("cannot decompress %d bytes, compressor %s, " |
180 | "error %d", in_len, compr->name, err); |
181 | |
182 | return err; |
183 | } |
184 | |
185 | /** |
186 | * compr_init - initialize a compressor. |
187 | * @compr: compressor description object |
188 | * |
189 | * This function initializes the requested compressor and returns zero in case |
190 | * of success or a negative error code in case of failure. |
191 | */ |
192 | static int __init compr_init(struct ubifs_compressor *compr) |
193 | { |
194 | if (compr->capi_name) { |
195 | compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0); |
196 | if (IS_ERR(compr->cc)) { |
197 | ubifs_err("cannot initialize compressor %s, error %ld", |
198 | compr->name, PTR_ERR(compr->cc)); |
199 | return PTR_ERR(compr->cc); |
200 | } |
201 | } |
202 | |
203 | ubifs_compressors[compr->compr_type] = compr; |
204 | return 0; |
205 | } |
206 | |
207 | /** |
208 | * compr_exit - de-initialize a compressor. |
209 | * @compr: compressor description object |
210 | */ |
211 | static void compr_exit(struct ubifs_compressor *compr) |
212 | { |
213 | if (compr->capi_name) |
214 | crypto_free_comp(compr->cc); |
215 | return; |
216 | } |
217 | |
218 | /** |
219 | * ubifs_compressors_init - initialize UBIFS compressors. |
220 | * |
221 | * This function initializes the compressor which were compiled in. Returns |
222 | * zero in case of success and a negative error code in case of failure. |
223 | */ |
224 | int __init ubifs_compressors_init(void) |
225 | { |
226 | int err; |
227 | |
228 | err = compr_init(&lzo_compr); |
229 | if (err) |
230 | return err; |
231 | |
232 | err = compr_init(&zlib_compr); |
233 | if (err) |
234 | goto out_lzo; |
235 | |
236 | ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr; |
237 | return 0; |
238 | |
239 | out_lzo: |
240 | compr_exit(&lzo_compr); |
241 | return err; |
242 | } |
243 | |
244 | /** |
245 | * ubifs_compressors_exit - de-initialize UBIFS compressors. |
246 | */ |
247 | void ubifs_compressors_exit(void) |
248 | { |
249 | compr_exit(&lzo_compr); |
250 | compr_exit(&zlib_compr); |
251 | } |
252 |
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