/* * 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){	int ret = 0;/* Registering compressors */	ret = jffs2_zlib_init();	if (ret)		goto exit;	ret = jffs2_rtime_init();	if (ret)		goto exit_zlib;	ret = jffs2_rubinmips_init();	if (ret)		goto exit_rtime;	ret = jffs2_dynrubin_init();	if (ret)		goto exit_runinmips;	ret = jffs2_lzo_init();	if (ret)		goto exit_dynrubin;  /* 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; exit_dynrubin:	jffs2_dynrubin_exit();exit_runinmips:	jffs2_rubinmips_exit();exit_rtime:	jffs2_rtime_exit();exit_zlib:	jffs2_zlib_exit();exit:	return ret;} int jffs2_compressors_exit(void){/* Unregistering compressors */	jffs2_lzo_exit();	jffs2_dynrubin_exit();	jffs2_rubinmips_exit();	jffs2_rtime_exit();	jffs2_zlib_exit();	return 0;}