[JFFS2] Remove stray __exit from jffs2_compressors_exit()
[linux-2.6.git] / fs / jffs2 / compr.c
1 /*
2  * JFFS2 -- Journalling Flash File System, Version 2.
3  *
4  * Copyright (C) 2001-2003 Red Hat, Inc.
5  * Created by Arjan van de Ven <arjanv@redhat.com>
6  *
7  * Copyright (C) 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  * $Id: compr.c,v 1.46 2005/11/07 11:14:38 gleixner Exp $
13  *
14  */
15
16 #include "compr.h"
17
18 static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
19
20 /* Available compressors are on this list */
21 static LIST_HEAD(jffs2_compressor_list);
22
23 /* Actual compression mode */
24 static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
25
26 /* Statistics for blocks stored without compression */
27 static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
28
29 /* jffs2_compress:
30  * @data: Pointer to uncompressed data
31  * @cdata: Pointer to returned pointer to buffer for compressed data
32  * @datalen: On entry, holds the amount of data available for compression.
33  *      On exit, expected to hold the amount of data actually compressed.
34  * @cdatalen: On entry, holds the amount of space available for compressed
35  *      data. On exit, expected to hold the actual size of the compressed
36  *      data.
37  *
38  * Returns: Lower byte to be stored with data indicating compression type used.
39  * Zero is used to show that the data could not be compressed - the
40  * compressed version was actually larger than the original.
41  * Upper byte will be used later. (soon)
42  *
43  * If the cdata buffer isn't large enough to hold all the uncompressed data,
44  * jffs2_compress should compress as much as will fit, and should set
45  * *datalen accordingly to show the amount of data which were compressed.
46  */
47 uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
48                              unsigned char *data_in, unsigned char **cpage_out,
49                              uint32_t *datalen, uint32_t *cdatalen)
50 {
51         int ret = JFFS2_COMPR_NONE;
52         int compr_ret;
53         struct jffs2_compressor *this, *best=NULL;
54         unsigned char *output_buf = NULL, *tmp_buf;
55         uint32_t orig_slen, orig_dlen;
56         uint32_t best_slen=0, best_dlen=0;
57
58         switch (jffs2_compression_mode) {
59         case JFFS2_COMPR_MODE_NONE:
60                 break;
61         case JFFS2_COMPR_MODE_PRIORITY:
62                 output_buf = kmalloc(*cdatalen,GFP_KERNEL);
63                 if (!output_buf) {
64                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. Compression failed.\n");
65                         goto out;
66                 }
67                 orig_slen = *datalen;
68                 orig_dlen = *cdatalen;
69                 spin_lock(&jffs2_compressor_list_lock);
70                 list_for_each_entry(this, &jffs2_compressor_list, list) {
71                         /* Skip decompress-only backwards-compatibility and disabled modules */
72                         if ((!this->compress)||(this->disabled))
73                                 continue;
74
75                         this->usecount++;
76                         spin_unlock(&jffs2_compressor_list_lock);
77                         *datalen  = orig_slen;
78                         *cdatalen = orig_dlen;
79                         compr_ret = this->compress(data_in, output_buf, datalen, cdatalen, NULL);
80                         spin_lock(&jffs2_compressor_list_lock);
81                         this->usecount--;
82                         if (!compr_ret) {
83                                 ret = this->compr;
84                                 this->stat_compr_blocks++;
85                                 this->stat_compr_orig_size += *datalen;
86                                 this->stat_compr_new_size  += *cdatalen;
87                                 break;
88                         }
89                 }
90                 spin_unlock(&jffs2_compressor_list_lock);
91                 if (ret == JFFS2_COMPR_NONE) kfree(output_buf);
92                 break;
93         case JFFS2_COMPR_MODE_SIZE:
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;
101                         /* Allocating memory for output buffer if necessary */
102                         if ((this->compr_buf_size<orig_dlen)&&(this->compr_buf)) {
103                                 spin_unlock(&jffs2_compressor_list_lock);
104                                 kfree(this->compr_buf);
105                                 spin_lock(&jffs2_compressor_list_lock);
106                                 this->compr_buf_size=0;
107                                 this->compr_buf=NULL;
108                         }
109                         if (!this->compr_buf) {
110                                 spin_unlock(&jffs2_compressor_list_lock);
111                                 tmp_buf = kmalloc(orig_dlen,GFP_KERNEL);
112                                 spin_lock(&jffs2_compressor_list_lock);
113                                 if (!tmp_buf) {
114                                         printk(KERN_WARNING "JFFS2: No memory for compressor allocation. (%d bytes)\n",orig_dlen);
115                                         continue;
116                                 }
117                                 else {
118                                         this->compr_buf = tmp_buf;
119                                         this->compr_buf_size = orig_dlen;
120                                 }
121                         }
122                         this->usecount++;
123                         spin_unlock(&jffs2_compressor_list_lock);
124                         *datalen  = orig_slen;
125                         *cdatalen = orig_dlen;
126                         compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen, NULL);
127                         spin_lock(&jffs2_compressor_list_lock);
128                         this->usecount--;
129                         if (!compr_ret) {
130                                 if ((!best_dlen)||(best_dlen>*cdatalen)) {
131                                         best_dlen = *cdatalen;
132                                         best_slen = *datalen;
133                                         best = this;
134                                 }
135                         }
136                 }
137                 if (best_dlen) {
138                         *cdatalen = best_dlen;
139                         *datalen  = best_slen;
140                         output_buf = best->compr_buf;
141                         best->compr_buf = NULL;
142                         best->compr_buf_size = 0;
143                         best->stat_compr_blocks++;
144                         best->stat_compr_orig_size += best_slen;
145                         best->stat_compr_new_size  += best_dlen;
146                         ret = best->compr;
147                 }
148                 spin_unlock(&jffs2_compressor_list_lock);
149                 break;
150         default:
151                 printk(KERN_ERR "JFFS2: unknow compression mode.\n");
152         }
153  out:
154         if (ret == JFFS2_COMPR_NONE) {
155                 *cpage_out = data_in;
156                 *datalen = *cdatalen;
157                 none_stat_compr_blocks++;
158                 none_stat_compr_size += *datalen;
159         }
160         else {
161                 *cpage_out = output_buf;
162         }
163         return ret;
164 }
165
166 int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
167                      uint16_t comprtype, unsigned char *cdata_in,
168                      unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
169 {
170         struct jffs2_compressor *this;
171         int ret;
172
173         /* Older code had a bug where it would write non-zero 'usercompr'
174            fields. Deal with it. */
175         if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
176                 comprtype &= 0xff;
177
178         switch (comprtype & 0xff) {
179         case JFFS2_COMPR_NONE:
180                 /* This should be special-cased elsewhere, but we might as well deal with it */
181                 memcpy(data_out, cdata_in, datalen);
182                 none_stat_decompr_blocks++;
183                 break;
184         case JFFS2_COMPR_ZERO:
185                 memset(data_out, 0, datalen);
186                 break;
187         default:
188                 spin_lock(&jffs2_compressor_list_lock);
189                 list_for_each_entry(this, &jffs2_compressor_list, list) {
190                         if (comprtype == this->compr) {
191                                 this->usecount++;
192                                 spin_unlock(&jffs2_compressor_list_lock);
193                                 ret = this->decompress(cdata_in, data_out, cdatalen, datalen, NULL);
194                                 spin_lock(&jffs2_compressor_list_lock);
195                                 if (ret) {
196                                         printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
197                                 }
198                                 else {
199                                         this->stat_decompr_blocks++;
200                                 }
201                                 this->usecount--;
202                                 spin_unlock(&jffs2_compressor_list_lock);
203                                 return ret;
204                         }
205                 }
206                 printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
207                 spin_unlock(&jffs2_compressor_list_lock);
208                 return -EIO;
209         }
210         return 0;
211 }
212
213 int jffs2_register_compressor(struct jffs2_compressor *comp)
214 {
215         struct jffs2_compressor *this;
216
217         if (!comp->name) {
218                 printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
219                 return -1;
220         }
221         comp->compr_buf_size=0;
222         comp->compr_buf=NULL;
223         comp->usecount=0;
224         comp->stat_compr_orig_size=0;
225         comp->stat_compr_new_size=0;
226         comp->stat_compr_blocks=0;
227         comp->stat_decompr_blocks=0;
228         D1(printk(KERN_DEBUG "Registering JFFS2 compressor \"%s\"\n", comp->name));
229
230         spin_lock(&jffs2_compressor_list_lock);
231
232         list_for_each_entry(this, &jffs2_compressor_list, list) {
233                 if (this->priority < comp->priority) {
234                         list_add(&comp->list, this->list.prev);
235                         goto out;
236                 }
237         }
238         list_add_tail(&comp->list, &jffs2_compressor_list);
239 out:
240         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
241                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
242         })
243
244         spin_unlock(&jffs2_compressor_list_lock);
245
246         return 0;
247 }
248
249 int jffs2_unregister_compressor(struct jffs2_compressor *comp)
250 {
251         D2(struct jffs2_compressor *this;)
252
253         D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
254
255         spin_lock(&jffs2_compressor_list_lock);
256
257         if (comp->usecount) {
258                 spin_unlock(&jffs2_compressor_list_lock);
259                 printk(KERN_WARNING "JFFS2: Compressor modul is in use. Unregister failed.\n");
260                 return -1;
261         }
262         list_del(&comp->list);
263
264         D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
265                 printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
266         })
267         spin_unlock(&jffs2_compressor_list_lock);
268         return 0;
269 }
270
271 #ifdef CONFIG_JFFS2_PROC
272
273 #define JFFS2_STAT_BUF_SIZE 16000
274
275 char *jffs2_list_compressors(void)
276 {
277         struct jffs2_compressor *this;
278         char *buf, *act_buf;
279
280         act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);
281         list_for_each_entry(this, &jffs2_compressor_list, list) {
282                 act_buf += sprintf(act_buf, "%10s priority:%d ", this->name, this->priority);
283                 if ((this->disabled)||(!this->compress))
284                         act_buf += sprintf(act_buf,"disabled");
285                 else
286                         act_buf += sprintf(act_buf,"enabled");
287                 act_buf += sprintf(act_buf,"\n");
288         }
289         return buf;
290 }
291
292 char *jffs2_stats(void)
293 {
294         struct jffs2_compressor *this;
295         char *buf, *act_buf;
296
297         act_buf = buf = kmalloc(JFFS2_STAT_BUF_SIZE,GFP_KERNEL);
298
299         act_buf += sprintf(act_buf,"JFFS2 compressor statistics:\n");
300         act_buf += sprintf(act_buf,"%10s   ","none");
301         act_buf += sprintf(act_buf,"compr: %d blocks (%d)  decompr: %d blocks\n", none_stat_compr_blocks,
302                            none_stat_compr_size, none_stat_decompr_blocks);
303         spin_lock(&jffs2_compressor_list_lock);
304         list_for_each_entry(this, &jffs2_compressor_list, list) {
305                 act_buf += sprintf(act_buf,"%10s ",this->name);
306                 if ((this->disabled)||(!this->compress))
307                         act_buf += sprintf(act_buf,"- ");
308                 else
309                         act_buf += sprintf(act_buf,"+ ");
310                 act_buf += sprintf(act_buf,"compr: %d blocks (%d/%d)  decompr: %d blocks ", this->stat_compr_blocks,
311                                    this->stat_compr_new_size, this->stat_compr_orig_size,
312                                    this->stat_decompr_blocks);
313                 act_buf += sprintf(act_buf,"\n");
314         }
315         spin_unlock(&jffs2_compressor_list_lock);
316
317         return buf;
318 }
319
320 char *jffs2_get_compression_mode_name(void)
321 {
322         switch (jffs2_compression_mode) {
323         case JFFS2_COMPR_MODE_NONE:
324                 return "none";
325         case JFFS2_COMPR_MODE_PRIORITY:
326                 return "priority";
327         case JFFS2_COMPR_MODE_SIZE:
328                 return "size";
329         }
330         return "unkown";
331 }
332
333 int jffs2_set_compression_mode_name(const char *name)
334 {
335         if (!strcmp("none",name)) {
336                 jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
337                 return 0;
338         }
339         if (!strcmp("priority",name)) {
340                 jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
341                 return 0;
342         }
343         if (!strcmp("size",name)) {
344                 jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
345                 return 0;
346         }
347         return 1;
348 }
349
350 static int jffs2_compressor_Xable(const char *name, int disabled)
351 {
352         struct jffs2_compressor *this;
353         spin_lock(&jffs2_compressor_list_lock);
354         list_for_each_entry(this, &jffs2_compressor_list, list) {
355                 if (!strcmp(this->name, name)) {
356                         this->disabled = disabled;
357                         spin_unlock(&jffs2_compressor_list_lock);
358                         return 0;
359                 }
360         }
361         spin_unlock(&jffs2_compressor_list_lock);
362         printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);
363         return 1;
364 }
365
366 int jffs2_enable_compressor_name(const char *name)
367 {
368         return jffs2_compressor_Xable(name, 0);
369 }
370
371 int jffs2_disable_compressor_name(const char *name)
372 {
373         return jffs2_compressor_Xable(name, 1);
374 }
375
376 int jffs2_set_compressor_priority(const char *name, int priority)
377 {
378         struct jffs2_compressor *this,*comp;
379         spin_lock(&jffs2_compressor_list_lock);
380         list_for_each_entry(this, &jffs2_compressor_list, list) {
381                 if (!strcmp(this->name, name)) {
382                         this->priority = priority;
383                         comp = this;
384                         goto reinsert;
385                 }
386         }
387         spin_unlock(&jffs2_compressor_list_lock);
388         printk(KERN_WARNING "JFFS2: compressor %s not found.\n",name);
389         return 1;
390 reinsert:
391         /* list is sorted in the order of priority, so if
392            we change it we have to reinsert it into the
393            good place */
394         list_del(&comp->list);
395         list_for_each_entry(this, &jffs2_compressor_list, list) {
396                 if (this->priority < comp->priority) {
397                         list_add(&comp->list, this->list.prev);
398                         spin_unlock(&jffs2_compressor_list_lock);
399                         return 0;
400                 }
401         }
402         list_add_tail(&comp->list, &jffs2_compressor_list);
403         spin_unlock(&jffs2_compressor_list_lock);
404         return 0;
405 }
406
407 #endif
408
409 void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
410 {
411         if (orig != comprbuf)
412                 kfree(comprbuf);
413 }
414
415 int __init jffs2_compressors_init(void)
416 {
417 /* Registering compressors */
418 #ifdef CONFIG_JFFS2_ZLIB
419         jffs2_zlib_init();
420 #endif
421 #ifdef CONFIG_JFFS2_RTIME
422         jffs2_rtime_init();
423 #endif
424 #ifdef CONFIG_JFFS2_RUBIN
425         jffs2_rubinmips_init();
426         jffs2_dynrubin_init();
427 #endif
428 /* Setting default compression mode */
429 #ifdef CONFIG_JFFS2_CMODE_NONE
430         jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
431         D1(printk(KERN_INFO "JFFS2: default compression mode: none\n");)
432 #else
433 #ifdef CONFIG_JFFS2_CMODE_SIZE
434         jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
435         D1(printk(KERN_INFO "JFFS2: default compression mode: size\n");)
436 #else
437         D1(printk(KERN_INFO "JFFS2: default compression mode: priority\n");)
438 #endif
439 #endif
440         return 0;
441 }
442
443 int jffs2_compressors_exit(void)
444 {
445 /* Unregistering compressors */
446 #ifdef CONFIG_JFFS2_RUBIN
447         jffs2_dynrubin_exit();
448         jffs2_rubinmips_exit();
449 #endif
450 #ifdef CONFIG_JFFS2_RTIME
451         jffs2_rtime_exit();
452 #endif
453 #ifdef CONFIG_JFFS2_ZLIB
454         jffs2_zlib_exit();
455 #endif
456         return 0;
457 }