[linux-2.6-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.
 *
 */

#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;
}
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	*/
1da177e4 LT	14
5a528957 JP	15	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5a528957 JP	16
1da177e4 LT	17	#include "compr.h"
	18
	19	static DEFINE_SPINLOCK(jffs2_compressor_list_lock);
	20
	21	/* Available compressors are on this list */
	22	static LIST_HEAD(jffs2_compressor_list);
	23
	24	/* Actual compression mode */
	25	static int jffs2_compression_mode = JFFS2_COMPR_MODE_PRIORITY;
	26
	27	/* Statistics for blocks stored without compression */
	28	static uint32_t none_stat_compr_blocks=0,none_stat_decompr_blocks=0,none_stat_compr_size=0;
	29
3b23c1f5 RP	30
	31	/*
	32	* Return 1 to use this compression
	33	*/
	34	static 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
123005f3 AS	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	*/
	74	static 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) {
5a528957	84	pr_warn("No memory for compressor allocation. Compression failed.\n");
123005f3 AS	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
1da177e4	130	/* jffs2_compress:
faa5c2a1 GU	131	* @data_in: Pointer to uncompressed data
faa5c2a1 GU	132	* @cpage_out: Pointer to returned pointer to buffer for compressed data
1da177e4 LT	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.
182ec4ee	140	* Zero is used to show that the data could not be compressed - the
1da177e4 LT	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,
182ec4ee	145	* jffs2_compress should compress as much as will fit, and should set
1da177e4 LT	146	* *datalen accordingly to show the amount of data which were compressed.
	147	*/
	148	uint16_t jffs2_compress(struct jffs2_sb_info c, struct jffs2_inode_info f,
ef53cb02 DW	149	unsigned char data_in, unsigned char *cpage_out,
ef53cb02 DW	150	uint32_t datalen, uint32_t cdatalen)
1da177e4 LT	151	{
1da177e4 LT	152	int ret = JFFS2_COMPR_NONE;
92abc475	153	int mode, compr_ret;
ef53cb02 DW	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;
1da177e4	158
92abc475 AS	159	if (c->mount_opts.override_compr)
	160	mode = c->mount_opts.compr;
	161	else
	162	mode = jffs2_compression_mode;
	163
	164	switch (mode) {
ef53cb02 DW	165	case JFFS2_COMPR_MODE_NONE:
	166	break;
	167	case JFFS2_COMPR_MODE_PRIORITY:
123005f3 AS	168	ret = jffs2_selected_compress(0, data_in, cpage_out, datalen,
123005f3 AS	169	cdatalen);
ef53cb02 DW	170	break;
ef53cb02 DW	171	case JFFS2_COMPR_MODE_SIZE:
3b23c1f5	172	case JFFS2_COMPR_MODE_FAVOURLZO:
ef53cb02 DW	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 */
3b23c1f5	181	if ((this->compr_buf_size < orig_slen) && (this->compr_buf)) {
ef53cb02 DW	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);
3b23c1f5	190	tmp_buf = kmalloc(orig_slen, GFP_KERNEL);
ef53cb02 DW	191	spin_lock(&jffs2_compressor_list_lock);
ef53cb02 DW	192	if (!tmp_buf) {
5a528957	193	pr_warn("No memory for compressor allocation. (%d bytes)\n",
da320f05	194	orig_slen);
ef53cb02 DW	195	continue;
	196	}
	197	else {
	198	this->compr_buf = tmp_buf;
3b23c1f5	199	this->compr_buf_size = orig_slen;
ef53cb02 DW	200	}
	201	}
	202	this->usecount++;
	203	spin_unlock(&jffs2_compressor_list_lock);
	204	*datalen = orig_slen;
	205	*cdatalen = orig_dlen;
088bd455	206	compr_ret = this->compress(data_in, this->compr_buf, datalen, cdatalen);
ef53cb02 DW	207	spin_lock(&jffs2_compressor_list_lock);
	208	this->usecount--;
	209	if (!compr_ret) {
3b23c1f5 RP	210	if (((!best_dlen) \|\| jffs2_is_best_compression(this, best, *cdatalen, best_dlen))
3b23c1f5 RP	211	&& (cdatalen < datalen)) {
ef53cb02 DW	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;
123005f3	228	*cpage_out = output_buf;
ef53cb02 DW	229	}
	230	spin_unlock(&jffs2_compressor_list_lock);
	231	break;
123005f3 AS	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;
ef53cb02	240	default:
5a528957	241	pr_err("unknown compression mode\n");
ef53cb02	242	}
123005f3	243
ef53cb02 DW	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	}
1da177e4 LT	250	return ret;
	251	}
	252
	253	int jffs2_decompress(struct jffs2_sb_info c, struct jffs2_inode_info f,
182ec4ee	254	uint16_t comprtype, unsigned char *cdata_in,
1da177e4 LT	255	unsigned char *data_out, uint32_t cdatalen, uint32_t datalen)
1da177e4 LT	256	{
ef53cb02 DW	257	struct jffs2_compressor *this;
ef53cb02 DW	258	int ret;
1da177e4 LT	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);
ef53cb02	269	none_stat_decompr_blocks++;
1da177e4 LT	270	break;
	271	case JFFS2_COMPR_ZERO:
	272	memset(data_out, 0, datalen);
	273	break;
	274	default:
ef53cb02 DW	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);
088bd455	280	ret = this->decompress(cdata_in, data_out, cdatalen, datalen);
ef53cb02 DW	281	spin_lock(&jffs2_compressor_list_lock);
ef53cb02 DW	282	if (ret) {
da320f05 JP	283	pr_warn("Decompressor \"%s\" returned %d\n",
da320f05 JP	284	this->name, ret);
ef53cb02 DW	285	}
	286	else {
	287	this->stat_decompr_blocks++;
	288	}
	289	this->usecount--;
	290	spin_unlock(&jffs2_compressor_list_lock);
	291	return ret;
	292	}
	293	}
5a528957	294	pr_warn("compression type 0x%02x not available\n", comprtype);
ef53cb02	295	spin_unlock(&jffs2_compressor_list_lock);
1da177e4 LT	296	return -EIO;
	297	}
	298	return 0;
	299	}
	300
	301	int jffs2_register_compressor(struct jffs2_compressor *comp)
	302	{
ef53cb02	303	struct jffs2_compressor *this;
1da177e4	304
ef53cb02	305	if (!comp->name) {
da320f05	306	pr_warn("NULL compressor name at registering JFFS2 compressor. Failed.\n");
ef53cb02 DW	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;
9c261b33	316	jffs2_dbg(1, "Registering JFFS2 compressor \"%s\"\n", comp->name);
1da177e4	317
ef53cb02	318	spin_lock(&jffs2_compressor_list_lock);
1da177e4	319
ef53cb02 DW	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);
1da177e4	327	out:
ef53cb02 DW	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	})
1da177e4	331
ef53cb02	332	spin_unlock(&jffs2_compressor_list_lock);
1da177e4	333
ef53cb02	334	return 0;
1da177e4 LT	335	}
	336
	337	int jffs2_unregister_compressor(struct jffs2_compressor *comp)
	338	{
9c261b33	339	D2(struct jffs2_compressor *this);
1da177e4	340
9c261b33	341	jffs2_dbg(1, "Unregistering JFFS2 compressor \"%s\"\n", comp->name);
1da177e4	342
ef53cb02	343	spin_lock(&jffs2_compressor_list_lock);
1da177e4	344
ef53cb02 DW	345	if (comp->usecount) {
ef53cb02 DW	346	spin_unlock(&jffs2_compressor_list_lock);
5a528957	347	pr_warn("Compressor module is in use. Unregister failed.\n");
ef53cb02 DW	348	return -1;
	349	}
	350	list_del(&comp->list);
1da177e4	351
ef53cb02 DW	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;
1da177e4 LT	357	}
1da177e4 LT	358
1da177e4 LT	359	void jffs2_free_comprbuf(unsigned char comprbuf, unsigned char orig)
1da177e4 LT	360	{
ef53cb02 DW	361	if (orig != comprbuf)
ef53cb02 DW	362	kfree(comprbuf);
1da177e4 LT	363	}
1da177e4 LT	364
7d2beb13	365	int __init jffs2_compressors_init(void)
1da177e4 LT	366	{
	367	/* Registering compressors */
	368	#ifdef CONFIG_JFFS2_ZLIB
ef53cb02	369	jffs2_zlib_init();
1da177e4 LT	370	#endif
1da177e4 LT	371	#ifdef CONFIG_JFFS2_RTIME
ef53cb02	372	jffs2_rtime_init();
1da177e4 LT	373	#endif
1da177e4 LT	374	#ifdef CONFIG_JFFS2_RUBIN
ef53cb02 DW	375	jffs2_rubinmips_init();
ef53cb02 DW	376	jffs2_dynrubin_init();
1da177e4	377	#endif
c799aca3 RP	378	#ifdef CONFIG_JFFS2_LZO
	379	jffs2_lzo_init();
	380	#endif
1da177e4 LT	381	/* Setting default compression mode */
1da177e4 LT	382	#ifdef CONFIG_JFFS2_CMODE_NONE
ef53cb02	383	jffs2_compression_mode = JFFS2_COMPR_MODE_NONE;
5a528957	384	jffs2_dbg(1, "default compression mode: none\n");
1da177e4 LT	385	#else
1da177e4 LT	386	#ifdef CONFIG_JFFS2_CMODE_SIZE
ef53cb02	387	jffs2_compression_mode = JFFS2_COMPR_MODE_SIZE;
5a528957	388	jffs2_dbg(1, "default compression mode: size\n");
3b23c1f5 RP	389	#else
	390	#ifdef CONFIG_JFFS2_CMODE_FAVOURLZO
	391	jffs2_compression_mode = JFFS2_COMPR_MODE_FAVOURLZO;
5a528957	392	jffs2_dbg(1, "default compression mode: favourlzo\n");
1da177e4	393	#else
5a528957	394	jffs2_dbg(1, "default compression mode: priority\n");
1da177e4	395	#endif
3b23c1f5	396	#endif
1da177e4	397	#endif
ef53cb02	398	return 0;
1da177e4 LT	399	}
1da177e4 LT	400
3bcc86f5	401	int jffs2_compressors_exit(void)
1da177e4 LT	402	{
1da177e4 LT	403	/* Unregistering compressors */
c799aca3 RP	404	#ifdef CONFIG_JFFS2_LZO
	405	jffs2_lzo_exit();
	406	#endif
1da177e4	407	#ifdef CONFIG_JFFS2_RUBIN
ef53cb02 DW	408	jffs2_dynrubin_exit();
ef53cb02 DW	409	jffs2_rubinmips_exit();
1da177e4 LT	410	#endif
1da177e4 LT	411	#ifdef CONFIG_JFFS2_RTIME
ef53cb02	412	jffs2_rtime_exit();
1da177e4 LT	413	#endif
1da177e4 LT	414	#ifdef CONFIG_JFFS2_ZLIB
ef53cb02	415	jffs2_zlib_exit();
1da177e4	416	#endif
ef53cb02	417	return 0;
1da177e4	418	}