Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 * Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
 *		    University of Szeged, Hungary
 *
 * Created by Arjan van de Ven <arjan@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include "compr.h"

static DEFINE_SPINLOCK(jffs2_compressor_list_lock);

/* Available compressors are on this list */
static LIST_HEAD(jffs2_compressor_list);

/* Actual compression mode */
static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;

/* Statistics for blocks stored without compression */
static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;


/*
 * Return 1 to use this compression
 */
static int jffs2_is_best_compression(struct jffs2_compressor *this,
		struct jffs2_compressor *best, uint32_t size, uint32_t bestsize)
{
	switch (jffs2_compression_mode) {
	case JFFS2_COMPR_MODE_SIZE:
		if (bestsize > size)
			return 1;
		return 0;
	case JFFS2_COMPR_MODE_FAVOURLZO:
		if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > size))
			return 1;
		if ((best->compr != JFFS2_COMPR_LZO) && (bestsize > size))
			return 1;
		if ((this->compr == JFFS2_COMPR_LZO) && (bestsize > (size * FAVOUR_LZO_PERCENT / 100)))
			return 1;
		if ((bestsize * FAVOUR_LZO_PERCENT / 100) > size)
			return 1;

		return 0;
	}
	/* Shouldn't happen */
	return 0;
}

/*
 * jffs2_selected_compress:
 * @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB).
 *	If 0, just take the first available compression mode.
 * @data_in: Pointer to uncompressed data
 * @cpage_out: Pointer to returned pointer to buffer for compressed data
 * @datalen: On entry, holds the amount of data available for compression.
 *	On exit, expected to hold the amount of data actually compressed.
 * @cdatalen: On entry, holds the amount of space available for compressed
 *	data. On exit, expected to hold the actual size of the compressed
 *	data.
 *
 * Returns: the compression type used.  Zero is used to show that the data
 * could not be compressed; probably because we couldn't find the requested
 * compression mode.
 */
static int jffs2_selected_compress(u8 compr, unsigned char *data_in,
		unsigned char **cpage_out, u32 *datalen, u32 *cdatalen)
{
	struct jffs2_compressor *this;
	int err, ret = JFFS2_COMPR_NONE;
	uint32_t orig_slen, orig_dlen;
	char *output_buf;

	output_buf = kmalloc(*cdatalen, GFP_KERNEL);
	if (!output_buf) {
		pr_warn("No memory for compressor allocation. Compression failed.\n");
		return ret;
	}
	orig_slen = *datalen;
	orig_dlen = *cdatalen;
	spin_lock(&jffs2_compressor_list_lock);
	list_for_each_entry(this, &jffs2_compressor_list, list) {
		/* Skip decompress-only and disabled modules */
		if (!this->compress || this->disabled)
			continue;

		/* Skip if not the desired compression type */
		if (compr && (compr != this->compr))
			continue;

		/*
		 * Either compression type was unspecified, or we found our
		 * compressor; either way, we're good to go.
		 */
		this->usecount++;
		spin_unlock(&jffs2_compressor_list_lock);

		*datalen  = orig_slen;
		*cdatalen = orig_dlen;
		err = this->compress(data_in, output_buf, datalen, cdatalen);

		spin_lock(&jffs2_compressor_list_lock);
		this->usecount--;
		if (!err) {
			/* Success */
			ret = this->compr;
			this->stat_compr_blocks++;
			this->stat_compr_orig_size += *datalen;
			this->stat_compr_new_size += *cdatalen;
			break;
		}
	}
	spin_unlock(&jffs2_compressor_list_lock);
	if (ret == JFFS2_COMPR_NONE)
		kfree(output_buf);
	else
		*cpage_out = output_buf;

	return ret;
}

/* jffs2_compress:
 * @data_in: Pointer to uncompressed data
 * @cpage_out: Pointer to returned pointer to buffer for compressed data
 * @datalen: On entry, holds the amount of data available for compression.
 *	On exit, expected to hold the amount of data actually compressed.
 * @cdatalen: On entry, holds the amount of space available for compressed
 *	data. On exit, expected to hold the actual size of the compressed
 *	data.
 *
 * Returns: Lower byte to be stored with data indicating compression type used.
 * Zero is used to show that the data could not be compressed - the
 * compressed version was actually larger than the original.
 * Upper byte will be used later. (soon)
 *
 * If the cdata buffer isn't large enough to hold all the uncompressed data,
 * jffs2_compress should compress as much as will fit, and should set
 * *datalen accordingly to show the amount of data which were compressed.
 */
uint16_t jffs2_compress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
			unsigned char *data_in, unsigned char **cpage_out,
			uint32_t *datalen, uint32_t *cdatalen)
{
	int ret = JFFS2_COMPR_NONE;
	int mode, compr_ret;
	struct jffs2_compressor *this, *best=NULL;
	unsigned char *output_buf = NULL, *tmp_buf;
	uint32_t orig_slen, orig_dlen;
	uint32_t best_slen=0, best_dlen=0;

	if (c->mount_opts.override_compr)
		mode = c->mount_opts.compr;
	else
		mode = jffs2_compression_mode;

	switch (mode) {
	case JFFS2_COMPR_MODE_NONE:
		break;
	case JFFS2_COMPR_MODE_PRIORITY:
		ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
				cdatalen);
		break;
	case JFFS2_COMPR_MODE_SIZE:
	case JFFS2_COMPR_MODE_FAVOURLZO:
		orig_slen = *datalen;
		orig_dlen = *cdatalen;
		spin_lock(&jffs2_compressor_list_lock);
		list_for_each_entry(this, &jffs2_compressor_list, list) {
			/* Skip decompress-only backwards-compatibility and disabled modules */
			if ((!this->compress)||(this->disabled))
				continue;
			/* Allocating memory for output buffer if necessary */
			if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
				spin_unlock(&jffs2_compressor_list_lock);
				kfree(this->compr_buf);
				spin_lock(&jffs2_compressor_list_lock);
				this->compr_buf_size=0;
				this->compr_buf=NULL;
			}
			if (!this->compr_buf) {
				spin_unlock(&jffs2_compressor_list_lock);
				tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
				spin_lock(&jffs2_compressor_list_lock);
				if (!tmp_buf) {
					pr_warn("No memory for compressor allocation. (%d bytes)\n",
						orig_slen);
					continue;
				}
				else {
					this->compr_buf = tmp_buf;
					this->compr_buf_size = orig_slen;
				}
			}
			this->usecount++;
			spin_unlock(&jffs2_compressor_list_lock);
			*datalen  = orig_slen;
			*cdatalen = orig_dlen;
			compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
			spin_lock(&jffs2_compressor_list_lock);
			this->usecount--;
			if (!compr_ret) {
				if (((!best_dlen) || jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
						&& (*cdatalen < *datalen)) {
					best_dlen = *cdatalen;
					best_slen = *datalen;
					best = this;
				}
			}
		}
		if (best_dlen) {
			*cdatalen = best_dlen;
			*datalen  = best_slen;
			output_buf = best->compr_buf;
			best->compr_buf = NULL;
			best->compr_buf_size = 0;
			best->stat_compr_blocks++;
			best->stat_compr_orig_size += best_slen;
			best->stat_compr_new_size  += best_dlen;
			ret = best->compr;
			*cpage_out = output_buf;
		}
		spin_unlock(&jffs2_compressor_list_lock);
		break;
	case JFFS2_COMPR_MODE_FORCELZO:
		ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in,
				cpage_out, datalen, cdatalen);
		break;
	case JFFS2_COMPR_MODE_FORCEZLIB:
		ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in,
				cpage_out, datalen, cdatalen);
		break;
	default:
		pr_err("unknown compression mode\n");
	}

	if (ret == JFFS2_COMPR_NONE) {
		*cpage_out = data_in;
		*datalen = *cdatalen;
		none_stat_compr_blocks++;
		none_stat_compr_size += *datalen;
	}
	return ret;
}

int jffs2_decompress(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
		     uint16_t comprtype, unsigned char *cdata_in,
		     unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
{
	struct jffs2_compressor *this;
	int ret;

	/* Older code had a bug where it would write non-zero 'usercompr'
	   fields. Deal with it. */
	if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
		comprtype &= 0xff;

	switch (comprtype & 0xff) {
	case JFFS2_COMPR_NONE:
		/* This should be special-cased elsewhere, but we might as well deal with it */
		memcpy(data_out, cdata_in, datalen);
		none_stat_decompr_blocks++;
		break;
	case JFFS2_COMPR_ZERO:
		memset(data_out, 0, datalen);
		break;
	default:
		spin_lock(&jffs2_compressor_list_lock);
		list_for_each_entry(this, &jffs2_compressor_list, list) {
			if (comprtype == this->compr) {
				this->usecount++;
				spin_unlock(&jffs2_compressor_list_lock);
				ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
				spin_lock(&jffs2_compressor_list_lock);
				if (ret) {
					pr_warn("Decompressor \"%s\" returned %d\n",
						this->name, ret);
				}
				else {
					this->stat_decompr_blocks++;
				}
				this->usecount--;
				spin_unlock(&jffs2_compressor_list_lock);
				return ret;
			}
		}
		pr_warn("compression type 0x%02x not available\n", comprtype);
		spin_unlock(&jffs2_compressor_list_lock);
		return -EIO;
	}
	return 0;
}

int jffs2_register_compressor(struct jffs2_compressor *comp)
{
	struct jffs2_compressor *this;

	if (!comp->name) {
		pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
		return -1;
	}
	comp->compr_buf_size=0;
	comp->compr_buf=NULL;
	comp->usecount=0;
	comp->stat_compr_orig_size=0;
	comp->stat_compr_new_size=0;
	comp->stat_compr_blocks=0;
	comp->stat_decompr_blocks=0;
	jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);

	spin_lock(&jffs2_compressor_list_lock);

	list_for_each_entry(this, &jffs2_compressor_list, list) {
		if (this->priority < comp->priority) {
			list_add(&comp->list, this->list.prev);
			goto out;
		}
	}
	list_add_tail(&comp->list, &jffs2_compressor_list);
out:
	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
	})

	spin_unlock(&jffs2_compressor_list_lock);

	return 0;
}

int jffs2_unregister_compressor(struct jffs2_compressor *comp)
{
	D2(struct jffs2_compressor *this);

	jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);

	spin_lock(&jffs2_compressor_list_lock);

	if (comp->usecount) {
		spin_unlock(&jffs2_compressor_list_lock);
		pr_warn("Compressor module is in use. Unregister failed.\n");
		return -1;
	}
	list_del(&comp->list);

	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
		printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
	})
	spin_unlock(&jffs2_compressor_list_lock);
	return 0;
}

void jffs2_free_comprbuf(unsigned char *comprbuf, unsigned char *orig)
{
	if (orig != comprbuf)
		kfree(comprbuf);
}

int __init jffs2_compressors_init(void)
{
/* Registering compressors */
#ifdef CONFIG_JFFS2_ZLIB
	jffs2_zlib_init();
#endif
#ifdef CONFIG_JFFS2_RTIME
	jffs2_rtime_init();
#endif
#ifdef CONFIG_JFFS2_RUBIN
	jffs2_rubinmips_init();
	jffs2_dynrubin_init();
#endif
#ifdef CONFIG_JFFS2_LZO
	jffs2_lzo_init();
#endif
/* Setting default compression mode */
#ifdef CONFIG_JFFS2_CMODE_NONE
	jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
	jffs2_dbg(1, "default compression mode: none\n");
#else
#ifdef CONFIG_JFFS2_CMODE_SIZE
	jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
	jffs2_dbg(1, "default compression mode: size\n");
#else
#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
	jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
	jffs2_dbg(1, "default compression mode: favourlzo\n");
#else
	jffs2_dbg(1, "default compression mode: priority\n");
#endif
#endif
#endif
	return 0;
}

int jffs2_compressors_exit(void)
{
/* Unregistering compressors */
#ifdef CONFIG_JFFS2_LZO
	jffs2_lzo_exit();
#endif
#ifdef CONFIG_JFFS2_RUBIN
	jffs2_dynrubin_exit();
	jffs2_rubinmips_exit();
#endif
#ifdef CONFIG_JFFS2_RTIME
	jffs2_rtime_exit();
#endif
#ifdef CONFIG_JFFS2_ZLIB
	jffs2_zlib_exit();
#endif
	return 0;
}