[linux-block.git] / fs / jffs2 / compr.c

/*
 * 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.
 *
 */

#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("JFFS2: 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("JFFS2: 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("JFFS2: 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("JFFS2 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("JFFS2: 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, "JFFS2: default compression mode: none\n");
#else
#ifdef CONFIG_JFFS2_CMODE_SIZE
	jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
	jffs2_dbg(1, "JFFS2: default compression mode: size\n");
#else
#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
	jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
	jffs2_dbg(1, "JFFS2: default compression mode: favourlzo\n");
#else
	jffs2_dbg(1, "JFFS2: 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;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* JFFS2 -- Journalling Flash File System, Version 2.
	3	*
c00c310e	4	* Copyright © 2001-2007 Red Hat, Inc.
6088c058	5	* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
c00c310e	6	* Copyright © 2004 Ferenc Havasi <havasi@inf.u-szeged.hu>,
ef53cb02	7	* University of Szeged, Hungary
1da177e4	8	*
6088c058 DW	9	* Created by Arjan van de Ven <arjan@infradead.org>
6088c058 DW	10	*
1da177e4 LT	11	* For licensing information, see the file 'LICENCE' in this directory.
1da177e4 LT	12	*
1da177e4 LT	13	*/
	14
	15	#include "compr.h"
	16
	17	static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
	18
	19	/* Available compressors are on this list */
	20	static LIST_HEAD(jffs2_compressor_list);
	21
	22	/* Actual compression mode */
	23	static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
	24
	25	/* Statistics for blocks stored without compression */
	26	static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
	27
3b23c1f5 RP	28
	29	/*
	30	* Return 1 to use this compression
	31	*/
	32	static 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
123005f3 AS	56	/*
	57	* jffs2_selected_compress:
	58	* @compr: Explicit compression type to use (ie, JFFS2_COMPR_ZLIB).
	59	* If 0, just take the first available compression mode.
	60	* @data_in: Pointer to uncompressed data
	61	* @cpage_out: Pointer to returned pointer to buffer for compressed data
	62	* @datalen: On entry, holds the amount of data available for compression.
	63	* On exit, expected to hold the amount of data actually compressed.
	64	* @cdatalen: On entry, holds the amount of space available for compressed
	65	* data. On exit, expected to hold the actual size of the compressed
	66	* data.
	67	*
	68	* Returns: the compression type used. Zero is used to show that the data
	69	* could not be compressed; probably because we couldn't find the requested
	70	* compression mode.
	71	*/
	72	static int jffs2_selected_compress(u8 compr, unsigned char *data_in,
	73	unsigned char *cpage_out, u32 datalen, u32 *cdatalen)
	74	{
	75	struct jffs2_compressor *this;
	76	int err, ret = JFFS2_COMPR_NONE;
	77	uint32_t orig_slen, orig_dlen;
	78	char *output_buf;
	79
	80	output_buf = kmalloc(*cdatalen, GFP_KERNEL);
	81	if (!output_buf) {
da320f05	82	pr_warn("JFFS2: No memory for compressor allocation. Compression failed.\n");
123005f3 AS	83	return ret;
	84	}
	85	orig_slen = *datalen;
	86	orig_dlen = *cdatalen;
	87	spin_lock(&jffs2_compressor_list_lock);
	88	list_for_each_entry(this, &jffs2_compressor_list, list) {
	89	/* Skip decompress-only and disabled modules */
	90	if (!this->compress \|\| this->disabled)
	91	continue;
	92
	93	/* Skip if not the desired compression type */
	94	if (compr && (compr != this->compr))
	95	continue;
	96
	97	/*
	98	* Either compression type was unspecified, or we found our
	99	* compressor; either way, we're good to go.
	100	*/
	101	this->usecount++;
	102	spin_unlock(&jffs2_compressor_list_lock);
	103
	104	*datalen = orig_slen;
	105	*cdatalen = orig_dlen;
	106	err = this->compress(data_in, output_buf, datalen, cdatalen);
	107
	108	spin_lock(&jffs2_compressor_list_lock);
	109	this->usecount--;
	110	if (!err) {
	111	/* Success */
	112	ret = this->compr;
	113	this->stat_compr_blocks++;
	114	this->stat_compr_orig_size += *datalen;
	115	this->stat_compr_new_size += *cdatalen;
	116	break;
	117	}
	118	}
	119	spin_unlock(&jffs2_compressor_list_lock);
	120	if (ret == JFFS2_COMPR_NONE)
	121	kfree(output_buf);
	122	else
	123	*cpage_out = output_buf;
	124
	125	return ret;
	126	}
	127
1da177e4	128	/* jffs2_compress:
faa5c2a1 GU	129	* @data_in: Pointer to uncompressed data
faa5c2a1 GU	130	* @cpage_out: Pointer to returned pointer to buffer for compressed data
1da177e4 LT	131	* @datalen: On entry, holds the amount of data available for compression.
	132	* On exit, expected to hold the amount of data actually compressed.
	133	* @cdatalen: On entry, holds the amount of space available for compressed
	134	* data. On exit, expected to hold the actual size of the compressed
	135	* data.
	136	*
	137	* Returns: Lower byte to be stored with data indicating compression type used.
182ec4ee	138	* Zero is used to show that the data could not be compressed - the
1da177e4 LT	139	* compressed version was actually larger than the original.
	140	* Upper byte will be used later. (soon)
	141	*
	142	* If the cdata buffer isn't large enough to hold all the uncompressed data,
182ec4ee	143	* jffs2_compress should compress as much as will fit, and should set
1da177e4 LT	144	* *datalen accordingly to show the amount of data which were compressed.
	145	*/
	146	uint16_t jffs2_compress(struct jffs2_sb_info c, struct jffs2_inode_info f,
ef53cb02 DW	147	unsigned char data_in, unsigned char *cpage_out,
ef53cb02 DW	148	uint32_t datalen, uint32_t cdatalen)
1da177e4 LT	149	{
1da177e4 LT	150	int ret = JFFS2_COMPR_NONE;
92abc475	151	int mode, compr_ret;
ef53cb02 DW	152	struct jffs2_compressor this, best=NULL;
	153	unsigned char output_buf = NULL, tmp_buf;
	154	uint32_t orig_slen, orig_dlen;
	155	uint32_t best_slen=0, best_dlen=0;
1da177e4	156
92abc475 AS	157	if (c->mount_opts.override_compr)
	158	mode = c->mount_opts.compr;
	159	else
	160	mode = jffs2_compression_mode;
	161
	162	switch (mode) {
ef53cb02 DW	163	case JFFS2_COMPR_MODE_NONE:
	164	break;
	165	case JFFS2_COMPR_MODE_PRIORITY:
123005f3 AS	166	ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
123005f3 AS	167	cdatalen);
ef53cb02 DW	168	break;
ef53cb02 DW	169	case JFFS2_COMPR_MODE_SIZE:
3b23c1f5	170	case JFFS2_COMPR_MODE_FAVOURLZO:
ef53cb02 DW	171	orig_slen = *datalen;
	172	orig_dlen = *cdatalen;
	173	spin_lock(&jffs2_compressor_list_lock);
	174	list_for_each_entry(this, &jffs2_compressor_list, list) {
	175	/* Skip decompress-only backwards-compatibility and disabled modules */
	176	if ((!this->compress)\|\|(this->disabled))
	177	continue;
	178	/* Allocating memory for output buffer if necessary */
3b23c1f5	179	if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
ef53cb02 DW	180	spin_unlock(&jffs2_compressor_list_lock);
	181	kfree(this->compr_buf);
	182	spin_lock(&jffs2_compressor_list_lock);
	183	this->compr_buf_size=0;
	184	this->compr_buf=NULL;
	185	}
	186	if (!this->compr_buf) {
	187	spin_unlock(&jffs2_compressor_list_lock);
3b23c1f5	188	tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
ef53cb02 DW	189	spin_lock(&jffs2_compressor_list_lock);
ef53cb02 DW	190	if (!tmp_buf) {
da320f05 JP	191	pr_warn("JFFS2: No memory for compressor allocation. (%d bytes)\n",
da320f05 JP	192	orig_slen);
ef53cb02 DW	193	continue;
	194	}
	195	else {
	196	this->compr_buf = tmp_buf;
3b23c1f5	197	this->compr_buf_size = orig_slen;
ef53cb02 DW	198	}
	199	}
	200	this->usecount++;
	201	spin_unlock(&jffs2_compressor_list_lock);
	202	*datalen = orig_slen;
	203	*cdatalen = orig_dlen;
088bd455	204	compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
ef53cb02 DW	205	spin_lock(&jffs2_compressor_list_lock);
	206	this->usecount--;
	207	if (!compr_ret) {
3b23c1f5 RP	208	if (((!best_dlen) \|\| jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
3b23c1f5 RP	209	&& (cdatalen < datalen)) {
ef53cb02 DW	210	best_dlen = *cdatalen;
	211	best_slen = *datalen;
	212	best = this;
	213	}
	214	}
	215	}
	216	if (best_dlen) {
	217	*cdatalen = best_dlen;
	218	*datalen = best_slen;
	219	output_buf = best->compr_buf;
	220	best->compr_buf = NULL;
	221	best->compr_buf_size = 0;
	222	best->stat_compr_blocks++;
	223	best->stat_compr_orig_size += best_slen;
	224	best->stat_compr_new_size += best_dlen;
	225	ret = best->compr;
123005f3	226	*cpage_out = output_buf;
ef53cb02 DW	227	}
	228	spin_unlock(&jffs2_compressor_list_lock);
	229	break;
123005f3 AS	230	case JFFS2_COMPR_MODE_FORCELZO:
	231	ret = jffs2_selected_compress(JFFS2_COMPR_LZO, data_in,
	232	cpage_out, datalen, cdatalen);
	233	break;
	234	case JFFS2_COMPR_MODE_FORCEZLIB:
	235	ret = jffs2_selected_compress(JFFS2_COMPR_ZLIB, data_in,
	236	cpage_out, datalen, cdatalen);
	237	break;
ef53cb02	238	default:
da320f05	239	pr_err("JFFS2: unknown compression mode\n");
ef53cb02	240	}
123005f3	241
ef53cb02 DW	242	if (ret == JFFS2_COMPR_NONE) {
	243	*cpage_out = data_in;
	244	datalen = cdatalen;
	245	none_stat_compr_blocks++;
	246	none_stat_compr_size += *datalen;
	247	}
1da177e4 LT	248	return ret;
	249	}
	250
	251	int jffs2_decompress(struct jffs2_sb_info c, struct jffs2_inode_info f,
182ec4ee	252	uint16_t comprtype, unsigned char *cdata_in,
1da177e4 LT	253	unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
1da177e4 LT	254	{
ef53cb02 DW	255	struct jffs2_compressor *this;
ef53cb02 DW	256	int ret;
1da177e4 LT	257
	258	/* Older code had a bug where it would write non-zero 'usercompr'
	259	fields. Deal with it. */
	260	if ((comprtype & 0xff) <= JFFS2_COMPR_ZLIB)
	261	comprtype &= 0xff;
	262
	263	switch (comprtype & 0xff) {
	264	case JFFS2_COMPR_NONE:
	265	/* This should be special-cased elsewhere, but we might as well deal with it */
	266	memcpy(data_out, cdata_in, datalen);
ef53cb02	267	none_stat_decompr_blocks++;
1da177e4 LT	268	break;
	269	case JFFS2_COMPR_ZERO:
	270	memset(data_out, 0, datalen);
	271	break;
	272	default:
ef53cb02 DW	273	spin_lock(&jffs2_compressor_list_lock);
	274	list_for_each_entry(this, &jffs2_compressor_list, list) {
	275	if (comprtype == this->compr) {
	276	this->usecount++;
	277	spin_unlock(&jffs2_compressor_list_lock);
088bd455	278	ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
ef53cb02 DW	279	spin_lock(&jffs2_compressor_list_lock);
ef53cb02 DW	280	if (ret) {
da320f05 JP	281	pr_warn("Decompressor \"%s\" returned %d\n",
da320f05 JP	282	this->name, ret);
ef53cb02 DW	283	}
	284	else {
	285	this->stat_decompr_blocks++;
	286	}
	287	this->usecount--;
	288	spin_unlock(&jffs2_compressor_list_lock);
	289	return ret;
	290	}
	291	}
da320f05 JP	292	pr_warn("JFFS2 compression type 0x%02x not available\n",
da320f05 JP	293	comprtype);
ef53cb02	294	spin_unlock(&jffs2_compressor_list_lock);
1da177e4 LT	295	return -EIO;
	296	}
	297	return 0;
	298	}
	299
	300	int jffs2_register_compressor(struct jffs2_compressor *comp)
	301	{
ef53cb02	302	struct jffs2_compressor *this;
1da177e4	303
ef53cb02	304	if (!comp->name) {
da320f05	305	pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
ef53cb02 DW	306	return -1;
	307	}
	308	comp->compr_buf_size=0;
	309	comp->compr_buf=NULL;
	310	comp->usecount=0;
	311	comp->stat_compr_orig_size=0;
	312	comp->stat_compr_new_size=0;
	313	comp->stat_compr_blocks=0;
	314	comp->stat_decompr_blocks=0;
9c261b33	315	jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);
1da177e4	316
ef53cb02	317	spin_lock(&jffs2_compressor_list_lock);
1da177e4	318
ef53cb02 DW	319	list_for_each_entry(this, &jffs2_compressor_list, list) {
	320	if (this->priority < comp->priority) {
	321	list_add(&comp->list, this->list.prev);
	322	goto out;
	323	}
	324	}
	325	list_add_tail(&comp->list, &jffs2_compressor_list);
1da177e4	326	out:
ef53cb02 DW	327	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
	328	printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
	329	})
1da177e4	330
ef53cb02	331	spin_unlock(&jffs2_compressor_list_lock);
1da177e4	332
ef53cb02	333	return 0;
1da177e4 LT	334	}
	335
	336	int jffs2_unregister_compressor(struct jffs2_compressor *comp)
	337	{
9c261b33	338	D2(struct jffs2_compressor *this);
1da177e4	339
9c261b33	340	jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);
1da177e4	341
ef53cb02	342	spin_lock(&jffs2_compressor_list_lock);
1da177e4	343
ef53cb02 DW	344	if (comp->usecount) {
ef53cb02 DW	345	spin_unlock(&jffs2_compressor_list_lock);
da320f05	346	pr_warn("JFFS2: Compressor module is in use. Unregister failed.\n");
ef53cb02 DW	347	return -1;
	348	}
	349	list_del(&comp->list);
1da177e4	350
ef53cb02 DW	351	D2(list_for_each_entry(this, &jffs2_compressor_list, list) {
	352	printk(KERN_DEBUG "Compressor \"%s\", prio %d\n", this->name, this->priority);
	353	})
	354	spin_unlock(&jffs2_compressor_list_lock);
	355	return 0;
1da177e4 LT	356	}
1da177e4 LT	357
1da177e4 LT	358	void jffs2_free_comprbuf(unsigned char comprbuf, unsigned char orig)
1da177e4 LT	359	{
ef53cb02 DW	360	if (orig != comprbuf)
ef53cb02 DW	361	kfree(comprbuf);
1da177e4 LT	362	}
1da177e4 LT	363
7d2beb13	364	int __init jffs2_compressors_init(void)
1da177e4 LT	365	{
	366	/* Registering compressors */
	367	#ifdef CONFIG_JFFS2_ZLIB
ef53cb02	368	jffs2_zlib_init();
1da177e4 LT	369	#endif
1da177e4 LT	370	#ifdef CONFIG_JFFS2_RTIME
ef53cb02	371	jffs2_rtime_init();
1da177e4 LT	372	#endif
1da177e4 LT	373	#ifdef CONFIG_JFFS2_RUBIN
ef53cb02 DW	374	jffs2_rubinmips_init();
ef53cb02 DW	375	jffs2_dynrubin_init();
1da177e4	376	#endif
c799aca3 RP	377	#ifdef CONFIG_JFFS2_LZO
	378	jffs2_lzo_init();
	379	#endif
1da177e4 LT	380	/* Setting default compression mode */
1da177e4 LT	381	#ifdef CONFIG_JFFS2_CMODE_NONE
ef53cb02	382	jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
9c261b33	383	jffs2_dbg(1, "JFFS2: default compression mode: none\n");
1da177e4 LT	384	#else
1da177e4 LT	385	#ifdef CONFIG_JFFS2_CMODE_SIZE
ef53cb02	386	jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
9c261b33	387	jffs2_dbg(1, "JFFS2: default compression mode: size\n");
3b23c1f5 RP	388	#else
	389	#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
	390	jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
9c261b33	391	jffs2_dbg(1, "JFFS2: default compression mode: favourlzo\n");
1da177e4	392	#else
9c261b33	393	jffs2_dbg(1, "JFFS2: default compression mode: priority\n");
1da177e4	394	#endif
3b23c1f5	395	#endif
1da177e4	396	#endif
ef53cb02	397	return 0;
1da177e4 LT	398	}
1da177e4 LT	399
3bcc86f5	400	int jffs2_compressors_exit(void)
1da177e4 LT	401	{
1da177e4 LT	402	/* Unregistering compressors */
c799aca3 RP	403	#ifdef CONFIG_JFFS2_LZO
	404	jffs2_lzo_exit();
	405	#endif
1da177e4	406	#ifdef CONFIG_JFFS2_RUBIN
ef53cb02 DW	407	jffs2_dynrubin_exit();
ef53cb02 DW	408	jffs2_rubinmips_exit();
1da177e4 LT	409	#endif
1da177e4 LT	410	#ifdef CONFIG_JFFS2_RTIME
ef53cb02	411	jffs2_rtime_exit();
1da177e4 LT	412	#endif
1da177e4 LT	413	#ifdef CONFIG_JFFS2_ZLIB
ef53cb02	414	jffs2_zlib_exit();
1da177e4	415	#endif
ef53cb02	416	return 0;
1da177e4	417	}