1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
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
8 *
9 * Created by Arjan van de Ven <arjan@infradead.org>
10 *
11 * For licensing information, see the file 'LICENCE' in this directory.
12 *
13 */
14
15#include "compr.h"
16
17static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
18
19/* Available compressors are on this list */
20static LIST_HEAD(jffs2_compressor_list);
21
22/* Actual compression mode */
23static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
24
25/* Statistics for blocks stored without compression */
26static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
27
28
29/*
30 * Return 1 to use this compression
31 */
32static int jffs2_is_best_compression(struct jffs2_compressor *this,
33		struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
34{
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;
49
50		return 0;
51	}
52	/* Shouldn't happen */
53	return 0;
54}
55
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.
64 *
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)
69 *
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.
73 */
74uint16_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)
77{
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;
84
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;
93		}
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
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, NULL);
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;
115			}
116		}
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;
137			}
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;
145				}
146				else {
147					this->compr_buf = tmp_buf;
148					this->compr_buf_size = orig_slen;
149				}
150			}
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, NULL);
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;
164				}
165			}
166		}
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;
177		}
178		spin_unlock(&jffs2_compressor_list_lock);
179		break;
180	default:
181		printk(KERN_ERR "JFFS2: unknown compression mode.\n");
182	}
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;
189	}
190	else {
191		*cpage_out = output_buf;
192	}
193	return ret;
194}
195
196int 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)
199{
200	struct jffs2_compressor *this;
201	int ret;
202
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;
207
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, NULL);
224				spin_lock(&jffs2_compressor_list_lock);
225				if (ret) {
226					printk(KERN_WARNING "Decompressor \"%s\" returned %d\n", this->name, ret);
227				}
228				else {
229					this->stat_decompr_blocks++;
230				}
231				this->usecount--;
232				spin_unlock(&jffs2_compressor_list_lock);
233				return ret;
234			}
235		}
236		printk(KERN_WARNING "JFFS2 compression type 0x%02x not available.\n", comprtype);
237		spin_unlock(&jffs2_compressor_list_lock);
238		return -EIO;
239	}
240	return 0;
241}
242
243int jffs2_register_compressor(struct jffs2_compressor *comp)
244{
245	struct jffs2_compressor *this;
246
247	if (!comp->name) {
248		printk(KERN_WARNING "NULL compressor name at registering JFFS2 compressor. Failed.\n");
249		return -1;
250	}
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));
259
260	spin_lock(&jffs2_compressor_list_lock);
261
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;
266		}
267	}
268	list_add_tail(&comp->list, &jffs2_compressor_list);
269out:
270	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
271		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
272	})
273
274	spin_unlock(&jffs2_compressor_list_lock);
275
276	return 0;
277}
278
279int jffs2_unregister_compressor(struct jffs2_compressor *comp)
280{
281	D2(struct jffs2_compressor *this;)
282
283	D1(printk(KERN_DEBUG "Unregistering JFFS2 compressor \"%s\"\n", comp->name));
284
285	spin_lock(&jffs2_compressor_list_lock);
286
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;
291	}
292	list_del(&comp->list);
293
294	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
295		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
296	})
297	spin_unlock(&jffs2_compressor_list_lock);
298	return 0;
299}
300
301void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
302{
303	if (orig != comprbuf)
304		kfree(comprbuf);
305}
306
307int __init jffs2_compressors_init(void)
308{
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;
341}
342
343int jffs2_compressors_exit(void)
344{
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;
360}
361