1 files changed, 426 insertions, 0 deletions

diff --git a/fs/jffs2/compr.c b/fs/jffs2/compr.c
new file mode 100644
index 0000000000..764f19dec3
--- /dev/null
+++ b/fs/jffs2/compr.c
@@ -0,0 +1,426 @@
+/*
+ * 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;
+}