[JFFS2] Tidy up licensing/copyright boilerplate.
[linux-2.6.git] / fs / jffs2 / compr.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright © 2001-2007 Red Hat, Inc.
5  * Created by Arjan van de Ven <arjanv@redhat.com>
6  *
7  * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
8  *                    University of Szeged, Hungary
9  *
10  * For licensing information, see the file 'LICENCE' in this directory.
11  *
12  */
13
14 #include "compr.h"
15
16 static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
17
18 /* Available compressors are on this list */
19 static LIST_HEAD(jffs2_compressor_list);
20
21 /* Actual compression mode */
22 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
23
24 /* Statistics for blocks stored without compression */
25 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
26
27 /* jffs2_compress:
28  * @data: Pointer to uncompressed data
29  * @cdata: Pointer to returned pointer to buffer for compressed data
30  * @datalen: On entry, holds the amount of data available for compression.
31  *      On exit, expected to hold the amount of data actually compressed.
32  * @cdatalen: On entry, holds the amount of space available for compressed
33  *      data. On exit, expected to hold the actual size of the compressed
34  *      data.
35  *
36  * Returns: Lower byte to be stored with data indicating compression type used.
37  * Zero is used to show that the data could not be compressed - the
38  * compressed version was actually larger than the original.
39  * Upper byte will be used later. (soon)
40  *
41  * If the cdata buffer isn't large enough to hold all the uncompressed data,
42  * jffs2_compress should compress as much as will fit, and should set
43  * *datalen accordingly to show the amount of data which were compressed.
44  */
45 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
46                              unsigned char *data_in, unsigned char **cpage_out,
47                              uint32_t *datalen, uint32_t *cdatalen)
48 {
49         int ret = JFFS2_COMPR_NONE;
50         int compr_ret;
51         struct jffs2_compressor *this, *best=NULL;
52         unsigned char *output_buf = NULL, *tmp_buf;
53         uint32_t orig_slen, orig_dlen;
54         uint32_t best_slen=0, best_dlen=0;
55
56         switch (jffs2_compression_mode) {
57         case JFFS2_COMPR_MODE_NONE:
58                 break;
59         case JFFS2_COMPR_MODE_PRIORITY:
60                 output_buf = kmalloc(*cdatalen,GFP_KERNEL);
61                 if (!output_buf) {
62                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
63                         goto out;
64                 }
65                 orig_slen = *datalen;
66                 orig_dlen = *cdatalen;
67                 spin_lock(&jffs2_compressor_list_lock);
68                 list_for_each_entry(this, &jffs2_compressor_list, list) {
69                         /* Skip decompress-only backwards-compatibility and disabled modules */
70                         if ((!this->compress)||(this->disabled))
71                                 continue;
72
73                         this->usecount++;
74                         spin_unlock(&jffs2_compressor_list_lock);
75                         *datalen  = orig_slen;
76                         *cdatalen = orig_dlen;
77                         compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL);
78                         spin_lock(&jffs2_compressor_list_lock);
79                         this->usecount--;
80                         if (!compr_ret) {
81                                 ret = this->compr;
82                                 this->stat_compr_blocks++;
83                                 this->stat_compr_orig_size += *datalen;
84                                 this->stat_compr_new_size  += *cdatalen;
85                                 break;
86                         }
87                 }
88                 spin_unlock(&jffs2_compressor_list_lock);
89                 if (ret == JFFS2_COMPR_NONE) kfree(output_buf);
90                 break;
91         case JFFS2_COMPR_MODE_SIZE:
92                 orig_slen = *datalen;
93                 orig_dlen = *cdatalen;
94                 spin_lock(&jffs2_compressor_list_lock);
95                 list_for_each_entry(this, &jffs2_compressor_list, list) {
96                         /* Skip decompress-only backwards-compatibility and disabled modules */
97                         if ((!this->compress)||(this->disabled))
98                                 continue;
99                         /* Allocating memory for output buffer if necessary */
100                         if ((this->compr_buf_size<orig_dlen)&&(this->compr_buf)) {
101                                 spin_unlock(&jffs2_compressor_list_lock);
102                                 kfree(this->compr_buf);
103                                 spin_lock(&jffs2_compressor_list_lock);
104                                 this->compr_buf_size=0;
105                                 this->compr_buf=NULL;
106                         }
107                         if (!this->compr_buf) {
108                                 spin_unlock(&jffs2_compressor_list_lock);
109                                 tmp_buf = kmalloc(orig_dlen,GFP_KERNEL);
110                                 spin_lock(&jffs2_compressor_list_lock);
111                                 if (!tmp_buf) {
112                                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n",orig_dlen);
113                                         continue;
114                                 }
115                                 else {
116                                         this->compr_buf = tmp_buf;
117                                         this->compr_buf_size = orig_dlen;
118                                 }
119                         }
120                         this->usecount++;
121                         spin_unlock(&jffs2_compressor_list_lock);
122                         *datalen  = orig_slen;
123                         *cdatalen = orig_dlen;
124                         compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL);
125                         spin_lock(&jffs2_compressor_list_lock);
126                         this->usecount--;
127                         if (!compr_ret) {
128                                 if ((!best_dlen)||(best_dlen>*cdatalen)) {
129                                         best_dlen = *cdatalen;
130                                         best_slen = *datalen;
131                                         best = this;
132                                 }
133                         }
134                 }
135                 if (best_dlen) {
136                         *cdatalen = best_dlen;
137                         *datalen  = best_slen;
138                         output_buf = best->compr_buf;
139                         best->compr_buf = NULL;
140                         best->compr_buf_size = 0;
141                         best->stat_compr_blocks++;
142                         best->stat_compr_orig_size += best_slen;
143                         best->stat_compr_new_size  += best_dlen;
144                         ret = best->compr;
145                 }
146                 spin_unlock(&jffs2_compressor_list_lock);
147                 break;
148         default:
149                 printk(KERN_ERR "JFFS2: unknow compression mode.\n");
150         }
151  out:
152         if (ret == JFFS2_COMPR_NONE) {
153                 *cpage_out = data_in;
154                 *datalen = *cdatalen;
155                 none_stat_compr_blocks++;
156                 none_stat_compr_size += *datalen;
157         }
158         else {
159                 *cpage_out = output_buf;
160         }
161         return ret;
162 }
163
164 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
165                      uint16_t comprtype, unsigned char *cdata_in,
166                      unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
167 {
168         struct jffs2_compressor *this;
169         int ret;
170
171         /* Older code had a bug where it would write non-zero 'usercompr'
172            fields. Deal with it. */
173         if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
174                 comprtype &= 0xff;
175
176         switch (comprtype & 0xff) {
177         case JFFS2_COMPR_NONE:
178                 /* This should be special-cased elsewhere, but we might as well deal with it */
179                 memcpy(data_out, cdata_in, datalen);
180                 none_stat_decompr_blocks++;
181                 break;
182         case JFFS2_COMPR_ZERO:
183                 memset(data_out, 0, datalen);
184                 break;
185         default:
186                 spin_lock(&jffs2_compressor_list_lock);
187                 list_for_each_entry(this, &jffs2_compressor_list, list) {
188                         if (comprtype == this->compr) {
189                                 this->usecount++;
190                                 spin_unlock(&jffs2_compressor_list_lock);
191                                 ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL);
192                                 spin_lock(&jffs2_compressor_list_lock);
193                                 if (ret) {
194                                         printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
195                                 }
196                                 else {
197                                         this->stat_decompr_blocks++;
198                                 }
199                                 this->usecount--;
200                                 spin_unlock(&jffs2_compressor_list_lock);
201                                 return ret;
202                         }
203                 }
204                 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
205                 spin_unlock(&jffs2_compressor_list_lock);
206                 return -EIO;
207         }
208         return 0;
209 }
210
211 int jffs2_register_compressor(struct jffs2_compressor *comp)
212 {
213         struct jffs2_compressor *this;
214
215         if (!comp->name) {
216                 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
217                 return -1;
218         }
219         comp->compr_buf_size=0;
220         comp->compr_buf=NULL;
221         comp->usecount=0;
222         comp->stat_compr_orig_size=0;
223         comp->stat_compr_new_size=0;
224         comp->stat_compr_blocks=0;
225         comp->stat_decompr_blocks=0;
226         D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
227
228         spin_lock(&jffs2_compressor_list_lock);
229
230         list_for_each_entry(this, &jffs2_compressor_list, list) {
231                 if (this->priority < comp->priority) {
232                         list_add(&comp->list, this->list.prev);
233                         goto out;
234                 }
235         }
236         list_add_tail(&comp->list, &jffs2_compressor_list);
237 out:
238         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
239                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
240         })
241
242         spin_unlock(&jffs2_compressor_list_lock);
243
244         return 0;
245 }
246
247 int jffs2_unregister_compressor(struct jffs2_compressor *comp)
248 {
249         D2(struct jffs2_compressor *this;)
250
251         D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
252
253         spin_lock(&jffs2_compressor_list_lock);
254
255         if (comp->usecount) {
256                 spin_unlock(&jffs2_compressor_list_lock);
257                 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
258                 return -1;
259         }
260         list_del(&comp->list);
261
262         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
263                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
264         })
265         spin_unlock(&jffs2_compressor_list_lock);
266         return 0;
267 }
268
269 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
270 {
271         if (orig != comprbuf)
272                 kfree(comprbuf);
273 }
274
275 int __init jffs2_compressors_init(void)
276 {
277 /* Registering compressors */
278 #ifdef CONFIG_JFFS2_ZLIB
279         jffs2_zlib_init();
280 #endif
281 #ifdef CONFIG_JFFS2_RTIME
282         jffs2_rtime_init();
283 #endif
284 #ifdef CONFIG_JFFS2_RUBIN
285         jffs2_rubinmips_init();
286         jffs2_dynrubin_init();
287 #endif
288 /* Setting default compression mode */
289 #ifdef CONFIG_JFFS2_CMODE_NONE
290         jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
291         D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
292 #else
293 #ifdef CONFIG_JFFS2_CMODE_SIZE
294         jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
295         D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
296 #else
297         D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
298 #endif
299 #endif
300         return 0;
301 }
302
303 int jffs2_compressors_exit(void)
304 {
305 /* Unregistering compressors */
306 #ifdef CONFIG_JFFS2_RUBIN
307         jffs2_dynrubin_exit();
308         jffs2_rubinmips_exit();
309 #endif
310 #ifdef CONFIG_JFFS2_RTIME
311         jffs2_rtime_exit();
312 #endif
313 #ifdef CONFIG_JFFS2_ZLIB
314         jffs2_zlib_exit();
315 #endif
316         return 0;
317 }