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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include "compr.h"
18
19static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
20
21/* Available compressors are on this list */
22static LIST_HEAD(jffs2_compressor_list);
23
24/* Actual compression mode */
25static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
26
27/* Statistics for blocks stored without compression */
28static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
29
30
31/*
32 * Return 1 to use this compression
33 */
34static int jffs2_is_best_compression(struct jffs2_compressor *this,
35		struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
36{
37	switch (jffs2_compression_mode) {
38	case JFFS2_COMPR_MODE_SIZE:
39		if (bestsize > size)
40			return 1;
41		return 0;
42	case JFFS2_COMPR_MODE_FAVOURLZO:
43		if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
44			return 1;
45		if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
46			return 1;
47		if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
48			return 1;
49		if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
50			return 1;
51
52		return 0;
53	}
54	/* Shouldn't happen */
55	return 0;
56}
57
58/*
59 * jffs2_selected_compress:
60 * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB).
61 *	If 0, just take the first available compression mode.
62 * @data_in: Pointer to uncompressed data
63 * @cpage_out: Pointer to returned pointer to buffer for compressed data
64 * @datalen: On entry, holds the amount of data available for compression.
65 *	On exit, expected to hold the amount of data actually compressed.
66 * @cdatalen: On entry, holds the amount of space available for compressed
67 *	data. On exit, expected to hold the actual size of the compressed
68 *	data.
69 *
70 * Returns: the compression type used.  Zero is used to show that the data
71 * could not be compressed; probably because we couldn't find the requested
72 * compression mode.
73 */
74static int jffs2_selected_compress(u8 compr, unsigned char *data_in,
75		unsigned char **cpage_out, u32 *datalen, u32 *cdatalen)
76{
77	struct jffs2_compressor *this;
78	int err, ret = JFFS2_COMPR_NONE;
79	uint32_t orig_slen, orig_dlen;
80	char *output_buf;
81
82	output_buf = kmalloc(*cdatalen, GFP_KERNEL);
83	if (!output_buf) {
84		pr_warn("No memory for compressor allocation. Compression failed.\n");
85		return ret;
86	}
87	orig_slen = *datalen;
88	orig_dlen = *cdatalen;
89	spin_lock(&jffs2_compressor_list_lock);
90	list_for_each_entry(this, &jffs2_compressor_list, list) {
91		/* Skip decompress-only and disabled modules */
92		if (!this->compress || this->disabled)
93			continue;
94
95		/* Skip if not the desired compression type */
96		if (compr && (compr != this->compr))
97			continue;
98
99		/*
100		 * Either compression type was unspecified, or we found our
101		 * compressor; either way, we're good to go.
102		 */
103		this->usecount++;
104		spin_unlock(&jffs2_compressor_list_lock);
105
106		*datalen  = orig_slen;
107		*cdatalen = orig_dlen;
108		err = this->compress(data_in, output_buf, datalen, cdatalen);
109
110		spin_lock(&jffs2_compressor_list_lock);
111		this->usecount--;
112		if (!err) {
113			/* Success */
114			ret = this->compr;
115			this->stat_compr_blocks++;
116			this->stat_compr_orig_size += *datalen;
117			this->stat_compr_new_size += *cdatalen;
118			break;
119		}
120	}
121	spin_unlock(&jffs2_compressor_list_lock);
122	if (ret == JFFS2_COMPR_NONE)
123		kfree(output_buf);
124	else
125		*cpage_out = output_buf;
126
127	return ret;
128}
129
130/* jffs2_compress:
131 * @data_in: Pointer to uncompressed data
132 * @cpage_out: Pointer to returned pointer to buffer for compressed data
133 * @datalen: On entry, holds the amount of data available for compression.
134 *	On exit, expected to hold the amount of data actually compressed.
135 * @cdatalen: On entry, holds the amount of space available for compressed
136 *	data. On exit, expected to hold the actual size of the compressed
137 *	data.
138 *
139 * Returns: Lower byte to be stored with data indicating compression type used.
140 * Zero is used to show that the data could not be compressed - the
141 * compressed version was actually larger than the original.
142 * Upper byte will be used later. (soon)
143 *
144 * If the cdata buffer isn't large enough to hold all the uncompressed data,
145 * jffs2_compress should compress as much as will fit, and should set
146 * *datalen accordingly to show the amount of data which were compressed.
147 */
148uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
149			unsigned char *data_in, unsigned char **cpage_out,
150			uint32_t *datalen, uint32_t *cdatalen)
151{
152	int ret = JFFS2_COMPR_NONE;
153	int mode, compr_ret;
154	struct jffs2_compressor *this, *best=NULL;
155	unsigned char *output_buf = NULL, *tmp_buf;
156	uint32_t orig_slen, orig_dlen;
157	uint32_t best_slen=0, best_dlen=0;
158
159	if (c->mount_opts.override_compr)
160		mode = c->mount_opts.compr;
161	else
162		mode = jffs2_compression_mode;
163
164	switch (mode) {
165	case JFFS2_COMPR_MODE_NONE:
166		break;
167	case JFFS2_COMPR_MODE_PRIORITY:
168		ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
169				cdatalen);
170		break;
171	case JFFS2_COMPR_MODE_SIZE:
172	case JFFS2_COMPR_MODE_FAVOURLZO:
173		orig_slen = *datalen;
174		orig_dlen = *cdatalen;
175		spin_lock(&jffs2_compressor_list_lock);
176		list_for_each_entry(this, &jffs2_compressor_list, list) {
177			/* Skip decompress-only backwards-compatibility and disabled modules */
178			if ((!this->compress)||(this->disabled))
179				continue;
180			/* Allocating memory for output buffer if necessary */
181			if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
182				spin_unlock(&jffs2_compressor_list_lock);
183				kfree(this->compr_buf);
184				spin_lock(&jffs2_compressor_list_lock);
185				this->compr_buf_size=0;
186				this->compr_buf=NULL;
187			}
188			if (!this->compr_buf) {
189				spin_unlock(&jffs2_compressor_list_lock);
190				tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
191				spin_lock(&jffs2_compressor_list_lock);
192				if (!tmp_buf) {
193					pr_warn("No memory for compressor allocation. (%d bytes)\n",
194						orig_slen);
195					continue;
196				}
197				else {
198					this->compr_buf = tmp_buf;
199					this->compr_buf_size = orig_slen;
200				}
201			}
202			this->usecount++;
203			spin_unlock(&jffs2_compressor_list_lock);
204			*datalen  = orig_slen;
205			*cdatalen = orig_dlen;
206			compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
207			spin_lock(&jffs2_compressor_list_lock);
208			this->usecount--;
209			if (!compr_ret) {
210				if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
211						&& (*cdatalen < *datalen)) {
212					best_dlen = *cdatalen;
213					best_slen = *datalen;
214					best = this;
215				}
216			}
217		}
218		if (best_dlen) {
219			*cdatalen = best_dlen;
220			*datalen  = best_slen;
221			output_buf = best->compr_buf;
222			best->compr_buf = NULL;
223			best->compr_buf_size = 0;
224			best->stat_compr_blocks++;
225			best->stat_compr_orig_size += best_slen;
226			best->stat_compr_new_size  += best_dlen;
227			ret = best->compr;
228			*cpage_out = output_buf;
229		}
230		spin_unlock(&jffs2_compressor_list_lock);
231		break;
232	case JFFS2_COMPR_MODE_FORCELZO:
233		ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in,
234				cpage_out, datalen, cdatalen);
235		break;
236	case JFFS2_COMPR_MODE_FORCEZLIB:
237		ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in,
238				cpage_out, datalen, cdatalen);
239		break;
240	default:
241		pr_err("unknown compression mode\n");
242	}
243
244	if (ret == JFFS2_COMPR_NONE) {
245		*cpage_out = data_in;
246		*datalen = *cdatalen;
247		none_stat_compr_blocks++;
248		none_stat_compr_size += *datalen;
249	}
250	return ret;
251}
252
253int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
254		     uint16_t comprtype, unsigned char *cdata_in,
255		     unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
256{
257	struct jffs2_compressor *this;
258	int ret;
259
260	/* Older code had a bug where it would write non-zero 'usercompr'
261	   fields. Deal with it. */
262	if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
263		comprtype &= 0xff;
264
265	switch (comprtype & 0xff) {
266	case JFFS2_COMPR_NONE:
267		/* This should be special-cased elsewhere, but we might as well deal with it */
268		memcpy(data_out, cdata_in, datalen);
269		none_stat_decompr_blocks++;
270		break;
271	case JFFS2_COMPR_ZERO:
272		memset(data_out, 0, datalen);
273		break;
274	default:
275		spin_lock(&jffs2_compressor_list_lock);
276		list_for_each_entry(this, &jffs2_compressor_list, list) {
277			if (comprtype == this->compr) {
278				this->usecount++;
279				spin_unlock(&jffs2_compressor_list_lock);
280				ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
281				spin_lock(&jffs2_compressor_list_lock);
282				if (ret) {
283					pr_warn("Decompressor \"%s\" returned %d\n",
284						this->name, ret);
285				}
286				else {
287					this->stat_decompr_blocks++;
288				}
289				this->usecount--;
290				spin_unlock(&jffs2_compressor_list_lock);
291				return ret;
292			}
293		}
294		pr_warn("compression type 0x%02x not available\n", comprtype);
295		spin_unlock(&jffs2_compressor_list_lock);
296		return -EIO;
297	}
298	return 0;
299}
300
301int jffs2_register_compressor(struct jffs2_compressor *comp)
302{
303	struct jffs2_compressor *this;
304
305	if (!comp->name) {
306		pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
307		return -1;
308	}
309	comp->compr_buf_size=0;
310	comp->compr_buf=NULL;
311	comp->usecount=0;
312	comp->stat_compr_orig_size=0;
313	comp->stat_compr_new_size=0;
314	comp->stat_compr_blocks=0;
315	comp->stat_decompr_blocks=0;
316	jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);
317
318	spin_lock(&jffs2_compressor_list_lock);
319
320	list_for_each_entry(this, &jffs2_compressor_list, list) {
321		if (this->priority < comp->priority) {
322			list_add(&comp->list, this->list.prev);
323			goto out;
324		}
325	}
326	list_add_tail(&comp->list, &jffs2_compressor_list);
327out:
328	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
329		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
330	})
331
332	spin_unlock(&jffs2_compressor_list_lock);
333
334	return 0;
335}
336
337int jffs2_unregister_compressor(struct jffs2_compressor *comp)
338{
339	D2(struct jffs2_compressor *this);
340
341	jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);
342
343	spin_lock(&jffs2_compressor_list_lock);
344
345	if (comp->usecount) {
346		spin_unlock(&jffs2_compressor_list_lock);
347		pr_warn("Compressor module is in use. Unregister failed.\n");
348		return -1;
349	}
350	list_del(&comp->list);
351
352	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
353		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
354	})
355	spin_unlock(&jffs2_compressor_list_lock);
356	return 0;
357}
358
359void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
360{
361	if (orig != comprbuf)
362		kfree(comprbuf);
363}
364
365int __init jffs2_compressors_init(void)
366{
367	int ret = 0;
368/* Registering compressors */
369	ret = jffs2_zlib_init();
370	if (ret)
371		goto exit;
372	ret = jffs2_rtime_init();
373	if (ret)
374		goto exit_zlib;
375	ret = jffs2_rubinmips_init();
376	if (ret)
377		goto exit_rtime;
378	ret = jffs2_dynrubin_init();
379	if (ret)
380		goto exit_runinmips;
381	ret = jffs2_lzo_init();
382	if (ret)
383		goto exit_dynrubin;
384
385
386/* Setting default compression mode */
387#ifdef CONFIG_JFFS2_CMODE_NONE
388	jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
389	jffs2_dbg(1, "default compression mode: none\n");
390#else
391#ifdef CONFIG_JFFS2_CMODE_SIZE
392	jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
393	jffs2_dbg(1, "default compression mode: size\n");
394#else
395#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
396	jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
397	jffs2_dbg(1, "default compression mode: favourlzo\n");
398#else
399	jffs2_dbg(1, "default compression mode: priority\n");
400#endif
401#endif
402#endif
403	return 0;
404
405exit_dynrubin:
406	jffs2_dynrubin_exit();
407exit_runinmips:
408	jffs2_rubinmips_exit();
409exit_rtime:
410	jffs2_rtime_exit();
411exit_zlib:
412	jffs2_zlib_exit();
413exit:
414	return ret;
415}
416
417int jffs2_compressors_exit(void)
418{
419/* Unregistering compressors */
420	jffs2_lzo_exit();
421	jffs2_dynrubin_exit();
422	jffs2_rubinmips_exit();
423	jffs2_rtime_exit();
424	jffs2_zlib_exit();
425	return 0;
426}
427