1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This file is part of UBIFS.
4 *
5 * Copyright (C) 2006-2008 Nokia Corporation.
6 * Copyright (C) 2006, 2007 University of Szeged, Hungary
7 *
8 * Authors: Adrian Hunter
9 *          Artem Bityutskiy (���������������� ����������)
10 *          Zoltan Sogor
11 */
12
13/*
14 * This file provides a single place to access to compression and
15 * decompression.
16 */
17
18#include <linux/crypto.h>
19#include "ubifs.h"
20
21/* Fake description object for the "none" compressor */
22static struct ubifs_compressor none_compr = {
23	.compr_type = UBIFS_COMPR_NONE,
24	.name = "none",
25	.capi_name = "",
26};
27
28#ifdef CONFIG_UBIFS_FS_LZO
29static DEFINE_MUTEX(lzo_mutex);
30
31static struct ubifs_compressor lzo_compr = {
32	.compr_type = UBIFS_COMPR_LZO,
33	.comp_mutex = &lzo_mutex,
34	.name = "lzo",
35	.capi_name = "lzo",
36};
37#else
38static struct ubifs_compressor lzo_compr = {
39	.compr_type = UBIFS_COMPR_LZO,
40	.name = "lzo",
41};
42#endif
43
44#ifdef CONFIG_UBIFS_FS_ZLIB
45static DEFINE_MUTEX(deflate_mutex);
46static DEFINE_MUTEX(inflate_mutex);
47
48static struct ubifs_compressor zlib_compr = {
49	.compr_type = UBIFS_COMPR_ZLIB,
50	.comp_mutex = &deflate_mutex,
51	.decomp_mutex = &inflate_mutex,
52	.name = "zlib",
53	.capi_name = "deflate",
54};
55#else
56static struct ubifs_compressor zlib_compr = {
57	.compr_type = UBIFS_COMPR_ZLIB,
58	.name = "zlib",
59};
60#endif
61
62#ifdef CONFIG_UBIFS_FS_ZSTD
63static DEFINE_MUTEX(zstd_enc_mutex);
64static DEFINE_MUTEX(zstd_dec_mutex);
65
66static struct ubifs_compressor zstd_compr = {
67	.compr_type = UBIFS_COMPR_ZSTD,
68	.comp_mutex = &zstd_enc_mutex,
69	.decomp_mutex = &zstd_dec_mutex,
70	.name = "zstd",
71	.capi_name = "zstd",
72};
73#else
74static struct ubifs_compressor zstd_compr = {
75	.compr_type = UBIFS_COMPR_ZSTD,
76	.name = "zstd",
77};
78#endif
79
80/* All UBIFS compressors */
81struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
82
83/**
84 * ubifs_compress - compress data.
85 * @in_buf: data to compress
86 * @in_len: length of the data to compress
87 * @out_buf: output buffer where compressed data should be stored
88 * @out_len: output buffer length is returned here
89 * @compr_type: type of compression to use on enter, actually used compression
90 *              type on exit
91 *
92 * This function compresses input buffer @in_buf of length @in_len and stores
93 * the result in the output buffer @out_buf and the resulting length in
94 * @out_len. If the input buffer does not compress, it is just copied to the
95 * @out_buf. The same happens if @compr_type is %UBIFS_COMPR_NONE or if
96 * compression error occurred.
97 *
98 * Note, if the input buffer was not compressed, it is copied to the output
99 * buffer and %UBIFS_COMPR_NONE is returned in @compr_type.
100 */
101void ubifs_compress(const struct ubifs_info *c, const void *in_buf,
102		    int in_len, void *out_buf, int *out_len, int *compr_type)
103{
104	int err;
105	struct ubifs_compressor *compr = ubifs_compressors[*compr_type];
106
107	if (*compr_type == UBIFS_COMPR_NONE)
108		goto no_compr;
109
110	/* If the input data is small, do not even try to compress it */
111	if (in_len < UBIFS_MIN_COMPR_LEN)
112		goto no_compr;
113
114	if (compr->comp_mutex)
115		mutex_lock(compr->comp_mutex);
116	err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,
117				   (unsigned int *)out_len);
118	if (compr->comp_mutex)
119		mutex_unlock(compr->comp_mutex);
120	if (unlikely(err)) {
121		ubifs_warn(c, "cannot compress %d bytes, compressor %s, error %d, leave data uncompressed",
122			   in_len, compr->name, err);
123		goto no_compr;
124	}
125
126	/*
127	 * If the data compressed only slightly, it is better to leave it
128	 * uncompressed to improve read speed.
129	 */
130	if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)
131		goto no_compr;
132
133	return;
134
135no_compr:
136	memcpy(out_buf, in_buf, in_len);
137	*out_len = in_len;
138	*compr_type = UBIFS_COMPR_NONE;
139}
140
141/**
142 * ubifs_decompress - decompress data.
143 * @in_buf: data to decompress
144 * @in_len: length of the data to decompress
145 * @out_buf: output buffer where decompressed data should
146 * @out_len: output length is returned here
147 * @compr_type: type of compression
148 *
149 * This function decompresses data from buffer @in_buf into buffer @out_buf.
150 * The length of the uncompressed data is returned in @out_len. This functions
151 * returns %0 on success or a negative error code on failure.
152 */
153int ubifs_decompress(const struct ubifs_info *c, const void *in_buf,
154		     int in_len, void *out_buf, int *out_len, int compr_type)
155{
156	int err;
157	struct ubifs_compressor *compr;
158
159	if (unlikely(compr_type < 0 || compr_type >= UBIFS_COMPR_TYPES_CNT)) {
160		ubifs_err(c, "invalid compression type %d", compr_type);
161		return -EINVAL;
162	}
163
164	compr = ubifs_compressors[compr_type];
165
166	if (unlikely(!compr->capi_name)) {
167		ubifs_err(c, "%s compression is not compiled in", compr->name);
168		return -EINVAL;
169	}
170
171	if (compr_type == UBIFS_COMPR_NONE) {
172		memcpy(out_buf, in_buf, in_len);
173		*out_len = in_len;
174		return 0;
175	}
176
177	if (compr->decomp_mutex)
178		mutex_lock(compr->decomp_mutex);
179	err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,
180				     (unsigned int *)out_len);
181	if (compr->decomp_mutex)
182		mutex_unlock(compr->decomp_mutex);
183	if (err)
184		ubifs_err(c, "cannot decompress %d bytes, compressor %s, error %d",
185			  in_len, compr->name, err);
186
187	return err;
188}
189
190/**
191 * compr_init - initialize a compressor.
192 * @compr: compressor description object
193 *
194 * This function initializes the requested compressor and returns zero in case
195 * of success or a negative error code in case of failure.
196 */
197static int __init compr_init(struct ubifs_compressor *compr)
198{
199	if (compr->capi_name) {
200		compr->cc = crypto_alloc_comp(compr->capi_name, 0, 0);
201		if (IS_ERR(compr->cc)) {
202			pr_err("UBIFS error (pid %d): cannot initialize compressor %s, error %ld",
203			       current->pid, compr->name, PTR_ERR(compr->cc));
204			return PTR_ERR(compr->cc);
205		}
206	}
207
208	ubifs_compressors[compr->compr_type] = compr;
209	return 0;
210}
211
212/**
213 * compr_exit - de-initialize a compressor.
214 * @compr: compressor description object
215 */
216static void compr_exit(struct ubifs_compressor *compr)
217{
218	if (compr->capi_name)
219		crypto_free_comp(compr->cc);
220}
221
222/**
223 * ubifs_compressors_init - initialize UBIFS compressors.
224 *
225 * This function initializes the compressor which were compiled in. Returns
226 * zero in case of success and a negative error code in case of failure.
227 */
228int __init ubifs_compressors_init(void)
229{
230	int err;
231
232	err = compr_init(&lzo_compr);
233	if (err)
234		return err;
235
236	err = compr_init(&zstd_compr);
237	if (err)
238		goto out_lzo;
239
240	err = compr_init(&zlib_compr);
241	if (err)
242		goto out_zstd;
243
244	ubifs_compressors[UBIFS_COMPR_NONE] = &none_compr;
245	return 0;
246
247out_zstd:
248	compr_exit(&zstd_compr);
249out_lzo:
250	compr_exit(&lzo_compr);
251	return err;
252}
253
254/**
255 * ubifs_compressors_exit - de-initialize UBIFS compressors.
256 */
257void ubifs_compressors_exit(void)
258{
259	compr_exit(&lzo_compr);
260	compr_exit(&zlib_compr);
261	compr_exit(&zstd_compr);
262}
263