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[linux-2.6/next.git] / fs / jffs2 / compr.c
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1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
4 * Copyright © 2001-2007 Red Hat, Inc.
5 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
6 * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
7 * University of Szeged, Hungary
9 * Created by Arjan van de Ven <arjan@infradead.org>
11 * For licensing information, see the file 'LICENCE' in this directory.
15 #include "compr.h"
17 static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
19 /* Available compressors are on this list */
20 static LIST_HEAD(jffs2_compressor_list);
22 /* Actual compression mode */
23 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
25 /* Statistics for blocks stored without compression */
26 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
30 * Return 1 to use this compression
32 static int jffs2_is_best_compression(struct jffs2_compressor *this,
33 struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
35 switch (jffs2_compression_mode) {
36 case JFFS2_COMPR_MODE_SIZE:
37 if (bestsize > size)
38 return 1;
39 return 0;
40 case JFFS2_COMPR_MODE_FAVOURLZO:
41 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
42 return 1;
43 if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
44 return 1;
45 if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
46 return 1;
47 if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
48 return 1;
50 return 0;
52 /* Shouldn't happen */
53 return 0;
56 /* jffs2_compress:
57 * @data_in: Pointer to uncompressed data
58 * @cpage_out: Pointer to returned pointer to buffer for compressed data
59 * @datalen: On entry, holds the amount of data available for compression.
60 * On exit, expected to hold the amount of data actually compressed.
61 * @cdatalen: On entry, holds the amount of space available for compressed
62 * data. On exit, expected to hold the actual size of the compressed
63 * data.
65 * Returns: Lower byte to be stored with data indicating compression type used.
66 * Zero is used to show that the data could not be compressed - the
67 * compressed version was actually larger than the original.
68 * Upper byte will be used later. (soon)
70 * If the cdata buffer isn't large enough to hold all the uncompressed data,
71 * jffs2_compress should compress as much as will fit, and should set
72 * *datalen accordingly to show the amount of data which were compressed.
74 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
75 unsigned char *data_in, unsigned char **cpage_out,
76 uint32_t *datalen, uint32_t *cdatalen)
78 int ret = JFFS2_COMPR_NONE;
79 int compr_ret;
80 struct jffs2_compressor *this, *best=NULL;
81 unsigned char *output_buf = NULL, *tmp_buf;
82 uint32_t orig_slen, orig_dlen;
83 uint32_t best_slen=0, best_dlen=0;
85 switch (jffs2_compression_mode) {
86 case JFFS2_COMPR_MODE_NONE:
87 break;
88 case JFFS2_COMPR_MODE_PRIORITY:
89 output_buf = kmalloc(*cdatalen,GFP_KERNEL);
90 if (!output_buf) {
91 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
92 goto out;
94 orig_slen = *datalen;
95 orig_dlen = *cdatalen;
96 spin_lock(&jffs2_compressor_list_lock);
97 list_for_each_entry(this, &jffs2_compressor_list, list) {
98 /* Skip decompress-only backwards-compatibility and disabled modules */
99 if ((!this->compress)||(this->disabled))
100 continue;
102 this->usecount++;
103 spin_unlock(&jffs2_compressor_list_lock);
104 *datalen = orig_slen;
105 *cdatalen = orig_dlen;
106 compr_ret = this->compress(data_in, output_buf, datalen, cdatalen);
107 spin_lock(&jffs2_compressor_list_lock);
108 this->usecount--;
109 if (!compr_ret) {
110 ret = this->compr;
111 this->stat_compr_blocks++;
112 this->stat_compr_orig_size += *datalen;
113 this->stat_compr_new_size += *cdatalen;
114 break;
117 spin_unlock(&jffs2_compressor_list_lock);
118 if (ret == JFFS2_COMPR_NONE)
119 kfree(output_buf);
120 break;
121 case JFFS2_COMPR_MODE_SIZE:
122 case JFFS2_COMPR_MODE_FAVOURLZO:
123 orig_slen = *datalen;
124 orig_dlen = *cdatalen;
125 spin_lock(&jffs2_compressor_list_lock);
126 list_for_each_entry(this, &jffs2_compressor_list, list) {
127 /* Skip decompress-only backwards-compatibility and disabled modules */
128 if ((!this->compress)||(this->disabled))
129 continue;
130 /* Allocating memory for output buffer if necessary */
131 if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
132 spin_unlock(&jffs2_compressor_list_lock);
133 kfree(this->compr_buf);
134 spin_lock(&jffs2_compressor_list_lock);
135 this->compr_buf_size=0;
136 this->compr_buf=NULL;
138 if (!this->compr_buf) {
139 spin_unlock(&jffs2_compressor_list_lock);
140 tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
141 spin_lock(&jffs2_compressor_list_lock);
142 if (!tmp_buf) {
143 printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n", orig_slen);
144 continue;
146 else {
147 this->compr_buf = tmp_buf;
148 this->compr_buf_size = orig_slen;
151 this->usecount++;
152 spin_unlock(&jffs2_compressor_list_lock);
153 *datalen = orig_slen;
154 *cdatalen = orig_dlen;
155 compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
156 spin_lock(&jffs2_compressor_list_lock);
157 this->usecount--;
158 if (!compr_ret) {
159 if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
160 && (*cdatalen < *datalen)) {
161 best_dlen = *cdatalen;
162 best_slen = *datalen;
163 best = this;
167 if (best_dlen) {
168 *cdatalen = best_dlen;
169 *datalen = best_slen;
170 output_buf = best->compr_buf;
171 best->compr_buf = NULL;
172 best->compr_buf_size = 0;
173 best->stat_compr_blocks++;
174 best->stat_compr_orig_size += best_slen;
175 best->stat_compr_new_size += best_dlen;
176 ret = best->compr;
178 spin_unlock(&jffs2_compressor_list_lock);
179 break;
180 default:
181 printk(KERN_ERR "JFFS2: unknown compression mode.\n");
183 out:
184 if (ret == JFFS2_COMPR_NONE) {
185 *cpage_out = data_in;
186 *datalen = *cdatalen;
187 none_stat_compr_blocks++;
188 none_stat_compr_size += *datalen;
190 else {
191 *cpage_out = output_buf;
193 return ret;
196 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
197 uint16_t comprtype, unsigned char *cdata_in,
198 unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
200 struct jffs2_compressor *this;
201 int ret;
203 /* Older code had a bug where it would write non-zero 'usercompr'
204 fields. Deal with it. */
205 if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
206 comprtype &= 0xff;
208 switch (comprtype & 0xff) {
209 case JFFS2_COMPR_NONE:
210 /* This should be special-cased elsewhere, but we might as well deal with it */
211 memcpy(data_out, cdata_in, datalen);
212 none_stat_decompr_blocks++;
213 break;
214 case JFFS2_COMPR_ZERO:
215 memset(data_out, 0, datalen);
216 break;
217 default:
218 spin_lock(&jffs2_compressor_list_lock);
219 list_for_each_entry(this, &jffs2_compressor_list, list) {
220 if (comprtype == this->compr) {
221 this->usecount++;
222 spin_unlock(&jffs2_compressor_list_lock);
223 ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
224 spin_lock(&jffs2_compressor_list_lock);
225 if (ret) {
226 printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
228 else {
229 this->stat_decompr_blocks++;
231 this->usecount--;
232 spin_unlock(&jffs2_compressor_list_lock);
233 return ret;
236 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
237 spin_unlock(&jffs2_compressor_list_lock);
238 return -EIO;
240 return 0;
243 int jffs2_register_compressor(struct jffs2_compressor *comp)
245 struct jffs2_compressor *this;
247 if (!comp->name) {
248 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
249 return -1;
251 comp->compr_buf_size=0;
252 comp->compr_buf=NULL;
253 comp->usecount=0;
254 comp->stat_compr_orig_size=0;
255 comp->stat_compr_new_size=0;
256 comp->stat_compr_blocks=0;
257 comp->stat_decompr_blocks=0;
258 D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
260 spin_lock(&jffs2_compressor_list_lock);
262 list_for_each_entry(this, &jffs2_compressor_list, list) {
263 if (this->priority < comp->priority) {
264 list_add(&comp->list, this->list.prev);
265 goto out;
268 list_add_tail(&comp->list, &jffs2_compressor_list);
269 out:
270 D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
271 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
274 spin_unlock(&jffs2_compressor_list_lock);
276 return 0;
279 int jffs2_unregister_compressor(struct jffs2_compressor *comp)
281 D2(struct jffs2_compressor *this;)
283 D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
285 spin_lock(&jffs2_compressor_list_lock);
287 if (comp->usecount) {
288 spin_unlock(&jffs2_compressor_list_lock);
289 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
290 return -1;
292 list_del(&comp->list);
294 D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
295 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
297 spin_unlock(&jffs2_compressor_list_lock);
298 return 0;
301 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
303 if (orig != comprbuf)
304 kfree(comprbuf);
307 int __init jffs2_compressors_init(void)
309 /* Registering compressors */
310 #ifdef CONFIG_JFFS2_ZLIB
311 jffs2_zlib_init();
312 #endif
313 #ifdef CONFIG_JFFS2_RTIME
314 jffs2_rtime_init();
315 #endif
316 #ifdef CONFIG_JFFS2_RUBIN
317 jffs2_rubinmips_init();
318 jffs2_dynrubin_init();
319 #endif
320 #ifdef CONFIG_JFFS2_LZO
321 jffs2_lzo_init();
322 #endif
323 /* Setting default compression mode */
324 #ifdef CONFIG_JFFS2_CMODE_NONE
325 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
326 D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
327 #else
328 #ifdef CONFIG_JFFS2_CMODE_SIZE
329 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
330 D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
331 #else
332 #ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
333 jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
334 D1(printk(KERN_INFO "JFFS2: default compression mode: favourlzo\n");)
335 #else
336 D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
337 #endif
338 #endif
339 #endif
340 return 0;
343 int jffs2_compressors_exit(void)
345 /* Unregistering compressors */
346 #ifdef CONFIG_JFFS2_LZO
347 jffs2_lzo_exit();
348 #endif
349 #ifdef CONFIG_JFFS2_RUBIN
350 jffs2_dynrubin_exit();
351 jffs2_rubinmips_exit();
352 #endif
353 #ifdef CONFIG_JFFS2_RTIME
354 jffs2_rtime_exit();
355 #endif
356 #ifdef CONFIG_JFFS2_ZLIB
357 jffs2_zlib_exit();
358 #endif
359 return 0;