Merge branch 'akpm' (updates from Andrew Morton)

Merge second patch-bomb from Andrew Morton:
 - misc fixes
 - audit stuff
 - fanotify/inotify/dnotify things
 - most of the rest of MM.  The new cache shrinker code from Glauber and
   Dave Chinner probably isn't quite stabilized yet.
 - ptrace
 - ipc
 - partitions
 - reboot cleanups
 - add LZ4 decompressor, use it for kernel compression

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (118 commits)
  lib/scatterlist: error handling in __sg_alloc_table()
  scsi_debug: fix do_device_access() with wrap around range
  crypto: talitos: use sg_pcopy_to_buffer()
  lib/scatterlist: introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer()
  lib/scatterlist: factor out sg_miter_get_next_page() from sg_miter_next()
  crypto: add lz4 Cryptographic API
  lib: add lz4 compressor module
  arm: add support for LZ4-compressed kernel
  lib: add support for LZ4-compressed kernel
  decompressor: add LZ4 decompressor module
  lib: add weak clz/ctz functions
  reboot: move arch/x86 reboot= handling to generic kernel
  reboot: arm: change reboot_mode to use enum reboot_mode
  reboot: arm: prepare reboot_mode for moving to generic kernel code
  reboot: arm: remove unused restart_mode fields from some arm subarchs
  reboot: unicore32: prepare reboot_mode for moving to generic kernel code
  reboot: x86: prepare reboot_mode for moving to generic kernel code
  reboot: checkpatch.pl the new kernel/reboot.c file
  reboot: move shutdown/reboot related functions to kernel/reboot.c
  reboot: remove -stable friendly PF_THREAD_BOUND define
  ...

5 files changed, 1467 insertions, 0 deletions

diff --git a/lib/lz4/Makefile b/lib/lz4/Makefile
new file mode 100644
index 000000000000..8085d04e9309
--- /dev/null
+++ b/lib/lz4/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_LZ4_COMPRESS) += lz4_compress.o
+obj-$(CONFIG_LZ4HC_COMPRESS) += lz4hc_compress.o
+obj-$(CONFIG_LZ4_DECOMPRESS) += lz4_decompress.o
diff --git a/lib/lz4/lz4_compress.c b/lib/lz4/lz4_compress.c
new file mode 100644
index 000000000000..fd94058bd7f9
--- /dev/null
+++ b/lib/lz4/lz4_compress.c
@@ -0,0 +1,443 @@
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011-2012, Yann Collet.
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You can contact the author at :
+ * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ * - LZ4 source repository : http://code.google.com/p/lz4/
+ *
+ *  Changed for kernel use by:
+ *  Chanho Min <chanho.min@lge.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <asm/unaligned.h>
+#include "lz4defs.h"
+
+/*
+ * LZ4_compressCtx :
+ * -----------------
+ * Compress 'isize' bytes from 'source' into an output buffer 'dest' of
+ * maximum size 'maxOutputSize'.  * If it cannot achieve it, compression
+ * will stop, and result of the function will be zero.
+ * return : the number of bytes written in buffer 'dest', or 0 if the
+ * compression fails
+ */
+static inline int lz4_compressctx(void *ctx,
+		const char *source,
+		char *dest,
+		int isize,
+		int maxoutputsize)
+{
+	HTYPE *hashtable = (HTYPE *)ctx;
+	const u8 *ip = (u8 *)source;
+#if LZ4_ARCH64
+	const BYTE * const base = ip;
+#else
+	const int base = 0;
+#endif
+	const u8 *anchor = ip;
+	const u8 *const iend = ip + isize;
+	const u8 *const mflimit = iend - MFLIMIT;
+	#define MATCHLIMIT (iend - LASTLITERALS)
+
+	u8 *op = (u8 *) dest;
+	u8 *const oend = op + maxoutputsize;
+	int length;
+	const int skipstrength = SKIPSTRENGTH;
+	u32 forwardh;
+	int lastrun;
+
+	/* Init */
+	if (isize < MINLENGTH)
+		goto _last_literals;
+
+	memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
+
+	/* First Byte */
+	hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
+	ip++;
+	forwardh = LZ4_HASH_VALUE(ip);
+
+	/* Main Loop */
+	for (;;) {
+		int findmatchattempts = (1U << skipstrength) + 3;
+		const u8 *forwardip = ip;
+		const u8 *ref;
+		u8 *token;
+
+		/* Find a match */
+		do {
+			u32 h = forwardh;
+			int step = findmatchattempts++ >> skipstrength;
+			ip = forwardip;
+			forwardip = ip + step;
+
+			if (unlikely(forwardip > mflimit))
+				goto _last_literals;
+
+			forwardh = LZ4_HASH_VALUE(forwardip);
+			ref = base + hashtable[h];
+			hashtable[h] = ip - base;
+		} while ((ref < ip - MAX_DISTANCE) || (A32(ref) != A32(ip)));
+
+		/* Catch up */
+		while ((ip > anchor) && (ref > (u8 *)source) &&
+			unlikely(ip[-1] == ref[-1])) {
+			ip--;
+			ref--;
+		}
+
+		/* Encode Literal length */
+		length = (int)(ip - anchor);
+		token = op++;
+		/* check output limit */
+		if (unlikely(op + length + (2 + 1 + LASTLITERALS) +
+			(length >> 8) > oend))
+			return 0;
+
+		if (length >= (int)RUN_MASK) {
+			int len;
+			*token = (RUN_MASK << ML_BITS);
+			len = length - RUN_MASK;
+			for (; len > 254 ; len -= 255)
+				*op++ = 255;
+			*op++ = (u8)len;
+		} else
+			*token = (length << ML_BITS);
+
+		/* Copy Literals */
+		LZ4_BLINDCOPY(anchor, op, length);
+_next_match:
+		/* Encode Offset */
+		LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
+
+		/* Start Counting */
+		ip += MINMATCH;
+		/* MinMatch verified */
+		ref += MINMATCH;
+		anchor = ip;
+		while (likely(ip < MATCHLIMIT - (STEPSIZE - 1))) {
+			#if LZ4_ARCH64
+			u64 diff = A64(ref) ^ A64(ip);
+			#else
+			u32 diff = A32(ref) ^ A32(ip);
+			#endif
+			if (!diff) {
+				ip += STEPSIZE;
+				ref += STEPSIZE;
+				continue;
+			}
+			ip += LZ4_NBCOMMONBYTES(diff);
+			goto _endcount;
+		}
+		#if LZ4_ARCH64
+		if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
+			ip += 4;
+			ref += 4;
+		}
+		#endif
+		if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
+			ip += 2;
+			ref += 2;
+		}
+		if ((ip < MATCHLIMIT) && (*ref == *ip))
+			ip++;
+_endcount:
+		/* Encode MatchLength */
+		length = (int)(ip - anchor);
+		/* Check output limit */
+		if (unlikely(op + (1 + LASTLITERALS) + (length >> 8) > oend))
+			return 0;
+		if (length >= (int)ML_MASK) {
+			*token += ML_MASK;
+			length -= ML_MASK;
+			for (; length > 509 ; length -= 510) {
+				*op++ = 255;
+				*op++ = 255;
+			}
+			if (length > 254) {
+				length -= 255;
+				*op++ = 255;
+			}
+			*op++ = (u8)length;
+		} else
+			*token += length;
+
+		/* Test end of chunk */
+		if (ip > mflimit) {
+			anchor = ip;
+			break;
+		}
+
+		/* Fill table */
+		hashtable[LZ4_HASH_VALUE(ip-2)] = ip - 2 - base;
+
+		/* Test next position */
+		ref = base + hashtable[LZ4_HASH_VALUE(ip)];
+		hashtable[LZ4_HASH_VALUE(ip)] = ip - base;
+		if ((ref > ip - (MAX_DISTANCE + 1)) && (A32(ref) == A32(ip))) {
+			token = op++;
+			*token = 0;
+			goto _next_match;
+		}
+
+		/* Prepare next loop */
+		anchor = ip++;
+		forwardh = LZ4_HASH_VALUE(ip);
+	}
+
+_last_literals:
+	/* Encode Last Literals */
+	lastrun = (int)(iend - anchor);
+	if (((char *)op - dest) + lastrun + 1
+		+ ((lastrun + 255 - RUN_MASK) / 255) > (u32)maxoutputsize)
+		return 0;
+
+	if (lastrun >= (int)RUN_MASK) {
+		*op++ = (RUN_MASK << ML_BITS);
+		lastrun -= RUN_MASK;
+		for (; lastrun > 254 ; lastrun -= 255)
+			*op++ = 255;
+		*op++ = (u8)lastrun;
+	} else
+		*op++ = (lastrun << ML_BITS);
+	memcpy(op, anchor, iend - anchor);
+	op += iend - anchor;
+
+	/* End */
+	return (int)(((char *)op) - dest);
+}
+
+static inline int lz4_compress64kctx(void *ctx,
+		const char *source,
+		char *dest,
+		int isize,
+		int maxoutputsize)
+{
+	u16 *hashtable = (u16 *)ctx;
+	const u8 *ip = (u8 *) source;
+	const u8 *anchor = ip;
+	const u8 *const base = ip;
+	const u8 *const iend = ip + isize;
+	const u8 *const mflimit = iend - MFLIMIT;
+	#define MATCHLIMIT (iend - LASTLITERALS)
+
+	u8 *op = (u8 *) dest;
+	u8 *const oend = op + maxoutputsize;
+	int len, length;
+	const int skipstrength = SKIPSTRENGTH;
+	u32 forwardh;
+	int lastrun;
+
+	/* Init */
+	if (isize < MINLENGTH)
+		goto _last_literals;
+
+	memset((void *)hashtable, 0, LZ4_MEM_COMPRESS);
+
+	/* First Byte */
+	ip++;
+	forwardh = LZ4_HASH64K_VALUE(ip);
+
+	/* Main Loop */
+	for (;;) {
+		int findmatchattempts = (1U << skipstrength) + 3;
+		const u8 *forwardip = ip;
+		const u8 *ref;
+		u8 *token;
+
+		/* Find a match */
+		do {
+			u32 h = forwardh;
+			int step = findmatchattempts++ >> skipstrength;
+			ip = forwardip;
+			forwardip = ip + step;
+
+			if (forwardip > mflimit)
+				goto _last_literals;
+
+			forwardh = LZ4_HASH64K_VALUE(forwardip);
+			ref = base + hashtable[h];
+			hashtable[h] = (u16)(ip - base);
+		} while (A32(ref) != A32(ip));
+
+		/* Catch up */
+		while ((ip > anchor) && (ref > (u8 *)source)
+			&& (ip[-1] == ref[-1])) {
+			ip--;
+			ref--;
+		}
+
+		/* Encode Literal length */
+		length = (int)(ip - anchor);
+		token = op++;
+		/* Check output limit */
+		if (unlikely(op + length + (2 + 1 + LASTLITERALS)
+			+ (length >> 8) > oend))
+			return 0;
+		if (length >= (int)RUN_MASK) {
+			*token = (RUN_MASK << ML_BITS);
+			len = length - RUN_MASK;
+			for (; len > 254 ; len -= 255)
+				*op++ = 255;
+			*op++ = (u8)len;
+		} else
+			*token = (length << ML_BITS);
+
+		/* Copy Literals */
+		LZ4_BLINDCOPY(anchor, op, length);
+
+_next_match:
+		/* Encode Offset */
+		LZ4_WRITE_LITTLEENDIAN_16(op, (u16)(ip - ref));
+
+		/* Start Counting */
+		ip += MINMATCH;
+		/* MinMatch verified */
+		ref += MINMATCH;
+		anchor = ip;
+
+		while (ip < MATCHLIMIT - (STEPSIZE - 1)) {
+			#if LZ4_ARCH64
+			u64 diff = A64(ref) ^ A64(ip);
+			#else
+			u32 diff = A32(ref) ^ A32(ip);
+			#endif
+
+			if (!diff) {
+				ip += STEPSIZE;
+				ref += STEPSIZE;
+				continue;
+			}
+			ip += LZ4_NBCOMMONBYTES(diff);
+			goto _endcount;
+		}
+		#if LZ4_ARCH64
+		if ((ip < (MATCHLIMIT - 3)) && (A32(ref) == A32(ip))) {
+			ip += 4;
+			ref += 4;
+		}
+		#endif
+		if ((ip < (MATCHLIMIT - 1)) && (A16(ref) == A16(ip))) {
+			ip += 2;
+			ref += 2;
+		}
+		if ((ip < MATCHLIMIT) && (*ref == *ip))
+			ip++;
+_endcount:
+
+		/* Encode MatchLength */
+		len = (int)(ip - anchor);
+		/* Check output limit */
+		if (unlikely(op + (1 + LASTLITERALS) + (len >> 8) > oend))
+			return 0;
+		if (len >= (int)ML_MASK) {
+			*token += ML_MASK;
+			len -= ML_MASK;
+			for (; len > 509 ; len -= 510) {
+				*op++ = 255;
+				*op++ = 255;
+			}
+			if (len > 254) {
+				len -= 255;
+				*op++ = 255;
+			}
+			*op++ = (u8)len;
+		} else
+			*token += len;
+
+		/* Test end of chunk */
+		if (ip > mflimit) {
+			anchor = ip;
+			break;
+		}
+
+		/* Fill table */
+		hashtable[LZ4_HASH64K_VALUE(ip-2)] = (u16)(ip - 2 - base);
+
+		/* Test next position */
+		ref = base + hashtable[LZ4_HASH64K_VALUE(ip)];
+		hashtable[LZ4_HASH64K_VALUE(ip)] = (u16)(ip - base);
+		if (A32(ref) == A32(ip)) {
+			token = op++;
+			*token = 0;
+			goto _next_match;
+		}
+
+		/* Prepare next loop */
+		anchor = ip++;
+		forwardh = LZ4_HASH64K_VALUE(ip);
+	}
+
+_last_literals:
+	/* Encode Last Literals */
+	lastrun = (int)(iend - anchor);
+	if (op + lastrun + 1 + (lastrun - RUN_MASK + 255) / 255 > oend)
+		return 0;
+	if (lastrun >= (int)RUN_MASK) {
+		*op++ = (RUN_MASK << ML_BITS);
+		lastrun -= RUN_MASK;
+		for (; lastrun > 254 ; lastrun -= 255)
+			*op++ = 255;
+		*op++ = (u8)lastrun;
+	} else
+		*op++ = (lastrun << ML_BITS);
+	memcpy(op, anchor, iend - anchor);
+	op += iend - anchor;
+	/* End */
+	return (int)(((char *)op) - dest);
+}
+
+int lz4_compress(const unsigned char *src, size_t src_len,
+			unsigned char *dst, size_t *dst_len, void *wrkmem)
+{
+	int ret = -1;
+	int out_len = 0;
+
+	if (src_len < LZ4_64KLIMIT)
+		out_len = lz4_compress64kctx(wrkmem, src, dst, src_len,
+				lz4_compressbound(src_len));
+	else
+		out_len = lz4_compressctx(wrkmem, src, dst, src_len,
+				lz4_compressbound(src_len));
+
+	if (out_len < 0)
+		goto exit;
+
+	*dst_len = out_len;
+
+	return 0;
+exit:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(lz4_compress);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZ4 compressor");
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
new file mode 100644
index 000000000000..d3414eae73a1
--- /dev/null
+++ b/lib/lz4/lz4_decompress.c
@@ -0,0 +1,326 @@
+/*
+ * LZ4 Decompressor for Linux kernel
+ *
+ * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
+ *
+ * Based on LZ4 implementation by Yann Collet.
+ *
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011-2012, Yann Collet.
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ *  You can contact the author at :
+ *  - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ *  - LZ4 source repository : http://code.google.com/p/lz4/
+ */
+
+#ifndef STATIC
+#include <linux/module.h>
+#include <linux/kernel.h>
+#endif
+#include <linux/lz4.h>
+
+#include <asm/unaligned.h>
+
+#include "lz4defs.h"
+
+static int lz4_uncompress(const char *source, char *dest, int osize)
+{
+	const BYTE *ip = (const BYTE *) source;
+	const BYTE *ref;
+	BYTE *op = (BYTE *) dest;
+	BYTE * const oend = op + osize;
+	BYTE *cpy;
+	unsigned token;
+	size_t length;
+	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+#if LZ4_ARCH64
+	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
+#endif
+
+	while (1) {
+
+		/* get runlength */
+		token = *ip++;
+		length = (token >> ML_BITS);
+		if (length == RUN_MASK) {
+			size_t len;
+
+			len = *ip++;
+			for (; len == 255; length += 255)
+				len = *ip++;
+			length += len;
+		}
+
+		/* copy literals */
+		cpy = op + length;
+		if (unlikely(cpy > oend - COPYLENGTH)) {
+			/*
+			 * Error: not enough place for another match
+			 * (min 4) + 5 literals
+			 */
+			if (cpy != oend)
+				goto _output_error;
+
+			memcpy(op, ip, length);
+			ip += length;
+			break; /* EOF */
+		}
+		LZ4_WILDCOPY(ip, op, cpy);
+		ip -= (op - cpy);
+		op = cpy;
+
+		/* get offset */
+		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
+		ip += 2;
+
+		/* Error: offset create reference outside destination buffer */
+		if (unlikely(ref < (BYTE *const) dest))
+			goto _output_error;
+
+		/* get matchlength */
+		length = token & ML_MASK;
+		if (length == ML_MASK) {
+			for (; *ip == 255; length += 255)
+				ip++;
+			length += *ip++;
+		}
+
+		/* copy repeated sequence */
+		if (unlikely((op - ref) < STEPSIZE)) {
+#if LZ4_ARCH64
+			size_t dec64 = dec64table[op - ref];
+#else
+			const int dec64 = 0;
+#endif
+			op[0] = ref[0];
+			op[1] = ref[1];
+			op[2] = ref[2];
+			op[3] = ref[3];
+			op += 4;
+			ref += 4;
+			ref -= dec32table[op-ref];
+			PUT4(ref, op);
+			op += STEPSIZE - 4;
+			ref -= dec64;
+		} else {
+			LZ4_COPYSTEP(ref, op);
+		}
+		cpy = op + length - (STEPSIZE - 4);
+		if (cpy > (oend - COPYLENGTH)) {
+
+			/* Error: request to write beyond destination buffer */
+			if (cpy > oend)
+				goto _output_error;
+			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
+			while (op < cpy)
+				*op++ = *ref++;
+			op = cpy;
+			/*
+			 * Check EOF (should never happen, since last 5 bytes
+			 * are supposed to be literals)
+			 */
+			if (op == oend)
+				goto _output_error;
+			continue;
+		}
+		LZ4_SECURECOPY(ref, op, cpy);
+		op = cpy; /* correction */
+	}
+	/* end of decoding */
+	return (int) (((char *)ip) - source);
+
+	/* write overflow error detected */
+_output_error:
+	return (int) (-(((char *)ip) - source));
+}
+
+static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
+				int isize, size_t maxoutputsize)
+{
+	const BYTE *ip = (const BYTE *) source;
+	const BYTE *const iend = ip + isize;
+	const BYTE *ref;
+
+
+	BYTE *op = (BYTE *) dest;
+	BYTE * const oend = op + maxoutputsize;
+	BYTE *cpy;
+
+	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+#if LZ4_ARCH64
+	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
+#endif
+
+	/* Main Loop */
+	while (ip < iend) {
+
+		unsigned token;
+		size_t length;
+
+		/* get runlength */
+		token = *ip++;
+		length = (token >> ML_BITS);
+		if (length == RUN_MASK) {
+			int s = 255;
+			while ((ip < iend) && (s == 255)) {
+				s = *ip++;
+				length += s;
+			}
+		}
+		/* copy literals */
+		cpy = op + length;
+		if ((cpy > oend - COPYLENGTH) ||
+			(ip + length > iend - COPYLENGTH)) {
+
+			if (cpy > oend)
+				goto _output_error;/* writes beyond buffer */
+
+			if (ip + length != iend)
+				goto _output_error;/*
+						    * Error: LZ4 format requires
+						    * to consume all input
+						    * at this stage
+						    */
+			memcpy(op, ip, length);
+			op += length;
+			break;/* Necessarily EOF, due to parsing restrictions */
+		}
+		LZ4_WILDCOPY(ip, op, cpy);
+		ip -= (op - cpy);
+		op = cpy;
+
+		/* get offset */
+		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
+		ip += 2;
+		if (ref < (BYTE * const) dest)
+			goto _output_error;
+			/*
+			 * Error : offset creates reference
+			 * outside of destination buffer
+			 */
+
+		/* get matchlength */
+		length = (token & ML_MASK);
+		if (length == ML_MASK) {
+			while (ip < iend) {
+				int s = *ip++;
+				length += s;
+				if (s == 255)
+					continue;
+				break;
+			}
+		}
+
+		/* copy repeated sequence */
+		if (unlikely((op - ref) < STEPSIZE)) {
+#if LZ4_ARCH64
+			size_t dec64 = dec64table[op - ref];
+#else
+			const int dec64 = 0;
+#endif
+				op[0] = ref[0];
+				op[1] = ref[1];
+				op[2] = ref[2];
+				op[3] = ref[3];
+				op += 4;
+				ref += 4;
+				ref -= dec32table[op - ref];
+				PUT4(ref, op);
+				op += STEPSIZE - 4;
+				ref -= dec64;
+		} else {
+			LZ4_COPYSTEP(ref, op);
+		}
+		cpy = op + length - (STEPSIZE-4);
+		if (cpy > oend - COPYLENGTH) {
+			if (cpy > oend)
+				goto _output_error; /* write outside of buf */
+
+			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
+			while (op < cpy)
+				*op++ = *ref++;
+			op = cpy;
+			/*
+			 * Check EOF (should never happen, since last 5 bytes
+			 * are supposed to be literals)
+			 */
+			if (op == oend)
+				goto _output_error;
+			continue;
+		}
+		LZ4_SECURECOPY(ref, op, cpy);
+		op = cpy; /* correction */
+	}
+	/* end of decoding */
+	return (int) (((char *) op) - dest);
+
+	/* write overflow error detected */
+_output_error:
+	return (int) (-(((char *) ip) - source));
+}
+
+int lz4_decompress(const char *src, size_t *src_len, char *dest,
+		size_t actual_dest_len)
+{
+	int ret = -1;
+	int input_len = 0;
+
+	input_len = lz4_uncompress(src, dest, actual_dest_len);
+	if (input_len < 0)
+		goto exit_0;
+	*src_len = input_len;
+
+	return 0;
+exit_0:
+	return ret;
+}
+#ifndef STATIC
+EXPORT_SYMBOL_GPL(lz4_decompress);
+#endif
+
+int lz4_decompress_unknownoutputsize(const char *src, size_t src_len,
+		char *dest, size_t *dest_len)
+{
+	int ret = -1;
+	int out_len = 0;
+
+	out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
+					*dest_len);
+	if (out_len < 0)
+		goto exit_0;
+	*dest_len = out_len;
+
+	return 0;
+exit_0:
+	return ret;
+}
+#ifndef STATIC
+EXPORT_SYMBOL_GPL(lz4_decompress_unknownoutputsize);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZ4 Decompressor");
+#endif
diff --git a/lib/lz4/lz4defs.h b/lib/lz4/lz4defs.h
new file mode 100644
index 000000000000..abcecdc2d0f2
--- /dev/null
+++ b/lib/lz4/lz4defs.h
@@ -0,0 +1,156 @@
+/*
+ * lz4defs.h -- architecture specific defines
+ *
+ * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ * Detects 64 bits mode
+ */
+#if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) \
+	|| defined(__ppc64__) || defined(__LP64__))
+#define LZ4_ARCH64 1
+#else
+#define LZ4_ARCH64 0
+#endif
+
+/*
+ * Architecture-specific macros
+ */
+#define BYTE	u8
+typedef struct _U16_S { u16 v; } U16_S;
+typedef struct _U32_S { u32 v; } U32_S;
+typedef struct _U64_S { u64 v; } U64_S;
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)		\
+	|| defined(CONFIG_ARM) && __LINUX_ARM_ARCH__ >= 6	\
+	&& defined(ARM_EFFICIENT_UNALIGNED_ACCESS)
+
+#define A16(x) (((U16_S *)(x))->v)
+#define A32(x) (((U32_S *)(x))->v)
+#define A64(x) (((U64_S *)(x))->v)
+
+#define PUT4(s, d) (A32(d) = A32(s))
+#define PUT8(s, d) (A64(d) = A64(s))
+#define LZ4_WRITE_LITTLEENDIAN_16(p, v)	\
+	do {	\
+		A16(p) = v; \
+		p += 2; \
+	} while (0)
+#else /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */
+
+#define A64(x) get_unaligned((u64 *)&(((U16_S *)(x))->v))
+#define A32(x) get_unaligned((u32 *)&(((U16_S *)(x))->v))
+#define A16(x) get_unaligned((u16 *)&(((U16_S *)(x))->v))
+
+#define PUT4(s, d) \
+	put_unaligned(get_unaligned((const u32 *) s), (u32 *) d)
+#define PUT8(s, d) \
+	put_unaligned(get_unaligned((const u64 *) s), (u64 *) d)
+
+#define LZ4_WRITE_LITTLEENDIAN_16(p, v)	\
+	do {	\
+		put_unaligned(v, (u16 *)(p)); \
+		p += 2; \
+	} while (0)
+#endif
+
+#define COPYLENGTH 8
+#define ML_BITS  4
+#define ML_MASK  ((1U << ML_BITS) - 1)
+#define RUN_BITS (8 - ML_BITS)
+#define RUN_MASK ((1U << RUN_BITS) - 1)
+#define MEMORY_USAGE	14
+#define MINMATCH	4
+#define SKIPSTRENGTH	6
+#define LASTLITERALS	5
+#define MFLIMIT		(COPYLENGTH + MINMATCH)
+#define MINLENGTH	(MFLIMIT + 1)
+#define MAXD_LOG	16
+#define MAXD		(1 << MAXD_LOG)
+#define MAXD_MASK	(u32)(MAXD - 1)
+#define MAX_DISTANCE	(MAXD - 1)
+#define HASH_LOG	(MAXD_LOG - 1)
+#define HASHTABLESIZE	(1 << HASH_LOG)
+#define MAX_NB_ATTEMPTS	256
+#define OPTIMAL_ML	(int)((ML_MASK-1)+MINMATCH)
+#define LZ4_64KLIMIT	((1<<16) + (MFLIMIT - 1))
+#define HASHLOG64K	((MEMORY_USAGE - 2) + 1)
+#define HASH64KTABLESIZE	(1U << HASHLOG64K)
+#define LZ4_HASH_VALUE(p)	(((A32(p)) * 2654435761U) >> \
+				((MINMATCH * 8) - (MEMORY_USAGE-2)))
+#define LZ4_HASH64K_VALUE(p)	(((A32(p)) * 2654435761U) >> \
+				((MINMATCH * 8) - HASHLOG64K))
+#define HASH_VALUE(p)		(((A32(p)) * 2654435761U) >> \
+				((MINMATCH * 8) - HASH_LOG))
+
+#if LZ4_ARCH64/* 64-bit */
+#define STEPSIZE 8
+
+#define LZ4_COPYSTEP(s, d)	\
+	do {			\
+		PUT8(s, d);	\
+		d += 8;		\
+		s += 8;		\
+	} while (0)
+
+#define LZ4_COPYPACKET(s, d)	LZ4_COPYSTEP(s, d)
+
+#define LZ4_SECURECOPY(s, d, e)			\
+	do {					\
+		if (d < e) {			\
+			LZ4_WILDCOPY(s, d, e);	\
+		}				\
+	} while (0)
+#define HTYPE u32
+
+#ifdef __BIG_ENDIAN
+#define LZ4_NBCOMMONBYTES(val) (__builtin_clzll(val) >> 3)
+#else
+#define LZ4_NBCOMMONBYTES(val) (__builtin_ctzll(val) >> 3)
+#endif
+
+#else	/* 32-bit */
+#define STEPSIZE 4
+
+#define LZ4_COPYSTEP(s, d)	\
+	do {			\
+		PUT4(s, d);	\
+		d += 4;		\
+		s += 4;		\
+	} while (0)
+
+#define LZ4_COPYPACKET(s, d)		\
+	do {				\
+		LZ4_COPYSTEP(s, d);	\
+		LZ4_COPYSTEP(s, d);	\
+	} while (0)
+
+#define LZ4_SECURECOPY	LZ4_WILDCOPY
+#define HTYPE const u8*
+
+#ifdef __BIG_ENDIAN
+#define LZ4_NBCOMMONBYTES(val) (__builtin_clz(val) >> 3)
+#else
+#define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3)
+#endif
+
+#endif
+
+#define LZ4_READ_LITTLEENDIAN_16(d, s, p) \
+	(d = s - get_unaligned_le16(p))
+
+#define LZ4_WILDCOPY(s, d, e)		\
+	do {				\
+		LZ4_COPYPACKET(s, d);	\
+	} while (d < e)
+
+#define LZ4_BLINDCOPY(s, d, l)	\
+	do {	\
+		u8 *e = (d) + l;	\
+		LZ4_WILDCOPY(s, d, e);	\
+		d = e;	\
+	} while (0)
diff --git a/lib/lz4/lz4hc_compress.c b/lib/lz4/lz4hc_compress.c
new file mode 100644
index 000000000000..eb1a74f5e368
--- /dev/null
+++ b/lib/lz4/lz4hc_compress.c
@@ -0,0 +1,539 @@
+/*
+ * LZ4 HC - High Compression Mode of LZ4
+ * Copyright (C) 2011-2012, Yann Collet.
+ * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You can contact the author at :
+ * - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
+ * - LZ4 source repository : http://code.google.com/p/lz4/
+ *
+ *  Changed for kernel use by:
+ *  Chanho Min <chanho.min@lge.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <asm/unaligned.h>
+#include "lz4defs.h"
+
+struct lz4hc_data {
+	const u8 *base;
+	HTYPE hashtable[HASHTABLESIZE];
+	u16 chaintable[MAXD];
+	const u8 *nexttoupdate;
+} __attribute__((__packed__));
+
+static inline int lz4hc_init(struct lz4hc_data *hc4, const u8 *base)
+{
+	memset((void *)hc4->hashtable, 0, sizeof(hc4->hashtable));
+	memset(hc4->chaintable, 0xFF, sizeof(hc4->chaintable));
+
+#if LZ4_ARCH64
+	hc4->nexttoupdate = base + 1;
+#else
+	hc4->nexttoupdate = base;
+#endif
+	hc4->base = base;
+	return 1;
+}
+
+/* Update chains up to ip (excluded) */
+static inline void lz4hc_insert(struct lz4hc_data *hc4, const u8 *ip)
+{
+	u16 *chaintable = hc4->chaintable;
+	HTYPE *hashtable  = hc4->hashtable;
+#if LZ4_ARCH64
+	const BYTE * const base = hc4->base;
+#else
+	const int base = 0;
+#endif
+
+	while (hc4->nexttoupdate < ip) {
+		const u8 *p = hc4->nexttoupdate;
+		size_t delta = p - (hashtable[HASH_VALUE(p)] + base);
+		if (delta > MAX_DISTANCE)
+			delta = MAX_DISTANCE;
+		chaintable[(size_t)(p) & MAXD_MASK] = (u16)delta;
+		hashtable[HASH_VALUE(p)] = (p) - base;
+		hc4->nexttoupdate++;
+	}
+}
+
+static inline size_t lz4hc_commonlength(const u8 *p1, const u8 *p2,
+		const u8 *const matchlimit)
+{
+	const u8 *p1t = p1;
+
+	while (p1t < matchlimit - (STEPSIZE - 1)) {
+#if LZ4_ARCH64
+		u64 diff = A64(p2) ^ A64(p1t);
+#else
+		u32 diff = A32(p2) ^ A32(p1t);
+#endif
+		if (!diff) {
+			p1t += STEPSIZE;
+			p2 += STEPSIZE;
+			continue;
+		}
+		p1t += LZ4_NBCOMMONBYTES(diff);
+		return p1t - p1;
+	}
+#if LZ4_ARCH64
+	if ((p1t < (matchlimit-3)) && (A32(p2) == A32(p1t))) {
+		p1t += 4;
+		p2 += 4;
+	}
+#endif
+
+	if ((p1t < (matchlimit - 1)) && (A16(p2) == A16(p1t))) {
+		p1t += 2;
+		p2 += 2;
+	}
+	if ((p1t < matchlimit) && (*p2 == *p1t))
+		p1t++;
+	return p1t - p1;
+}
+
+static inline int lz4hc_insertandfindbestmatch(struct lz4hc_data *hc4,
+		const u8 *ip, const u8 *const matchlimit, const u8 **matchpos)
+{
+	u16 *const chaintable = hc4->chaintable;
+	HTYPE *const hashtable = hc4->hashtable;
+	const u8 *ref;
+#if LZ4_ARCH64
+	const BYTE * const base = hc4->base;
+#else
+	const int base = 0;
+#endif
+	int nbattempts = MAX_NB_ATTEMPTS;
+	size_t repl = 0, ml = 0;
+	u16 delta;
+
+	/* HC4 match finder */
+	lz4hc_insert(hc4, ip);
+	ref = hashtable[HASH_VALUE(ip)] + base;
+
+	/* potential repetition */
+	if (ref >= ip-4) {
+		/* confirmed */
+		if (A32(ref) == A32(ip)) {
+			delta = (u16)(ip-ref);
+			repl = ml  = lz4hc_commonlength(ip + MINMATCH,
+					ref + MINMATCH, matchlimit) + MINMATCH;
+			*matchpos = ref;
+		}
+		ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK];
+	}
+
+	while ((ref >= ip - MAX_DISTANCE) && nbattempts) {
+		nbattempts--;
+		if (*(ref + ml) == *(ip + ml)) {
+			if (A32(ref) == A32(ip)) {
+				size_t mlt =
+					lz4hc_commonlength(ip + MINMATCH,
+					ref + MINMATCH, matchlimit) + MINMATCH;
+				if (mlt > ml) {
+					ml = mlt;
+					*matchpos = ref;
+				}
+			}
+		}
+		ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK];
+	}
+
+	/* Complete table */
+	if (repl) {
+		const BYTE *ptr = ip;
+		const BYTE *end;
+		end = ip + repl - (MINMATCH-1);
+		/* Pre-Load */
+		while (ptr < end - delta) {
+			chaintable[(size_t)(ptr) & MAXD_MASK] = delta;
+			ptr++;
+		}
+		do {
+			chaintable[(size_t)(ptr) & MAXD_MASK] = delta;
+			/* Head of chain */
+			hashtable[HASH_VALUE(ptr)] = (ptr) - base;
+			ptr++;
+		} while (ptr < end);
+		hc4->nexttoupdate = end;
+	}
+
+	return (int)ml;
+}
+
+static inline int lz4hc_insertandgetwidermatch(struct lz4hc_data *hc4,
+	const u8 *ip, const u8 *startlimit, const u8 *matchlimit, int longest,
+	const u8 **matchpos, const u8 **startpos)
+{
+	u16 *const chaintable = hc4->chaintable;
+	HTYPE *const hashtable = hc4->hashtable;
+#if LZ4_ARCH64
+	const BYTE * const base = hc4->base;
+#else
+	const int base = 0;
+#endif
+	const u8 *ref;
+	int nbattempts = MAX_NB_ATTEMPTS;
+	int delta = (int)(ip - startlimit);
+
+	/* First Match */
+	lz4hc_insert(hc4, ip);
+	ref = hashtable[HASH_VALUE(ip)] + base;
+
+	while ((ref >= ip - MAX_DISTANCE) && (ref >= hc4->base)
+		&& (nbattempts)) {
+		nbattempts--;
+		if (*(startlimit + longest) == *(ref - delta + longest)) {
+			if (A32(ref) == A32(ip)) {
+				const u8 *reft = ref + MINMATCH;
+				const u8 *ipt = ip + MINMATCH;
+				const u8 *startt = ip;
+
+				while (ipt < matchlimit-(STEPSIZE - 1)) {
+					#if LZ4_ARCH64
+					u64 diff = A64(reft) ^ A64(ipt);
+					#else
+					u32 diff = A32(reft) ^ A32(ipt);
+					#endif
+
+					if (!diff) {
+						ipt += STEPSIZE;
+						reft += STEPSIZE;
+						continue;
+					}
+					ipt += LZ4_NBCOMMONBYTES(diff);
+					goto _endcount;
+				}
+				#if LZ4_ARCH64
+				if ((ipt < (matchlimit - 3))
+					&& (A32(reft) == A32(ipt))) {
+					ipt += 4;
+					reft += 4;
+				}
+				ipt += 2;
+				#endif
+				if ((ipt < (matchlimit - 1))
+					&& (A16(reft) == A16(ipt))) {
+					reft += 2;
+				}
+				if ((ipt < matchlimit) && (*reft == *ipt))
+					ipt++;
+_endcount:
+				reft = ref;
+
+				while ((startt > startlimit)
+					&& (reft > hc4->base)
+					&& (startt[-1] == reft[-1])) {
+					startt--;
+					reft--;
+				}
+
+				if ((ipt - startt) > longest) {
+					longest = (int)(ipt - startt);
+					*matchpos = reft;
+					*startpos = startt;
+				}
+			}
+		}
+		ref -= (size_t)chaintable[(size_t)(ref) & MAXD_MASK];
+	}
+	return longest;
+}
+
+static inline int lz4_encodesequence(const u8 **ip, u8 **op, const u8 **anchor,
+		int ml, const u8 *ref)
+{
+	int length, len;
+	u8 *token;
+
+	/* Encode Literal length */
+	length = (int)(*ip - *anchor);
+	token = (*op)++;
+	if (length >= (int)RUN_MASK) {
+		*token = (RUN_MASK << ML_BITS);
+		len = length - RUN_MASK;
+		for (; len > 254 ; len -= 255)
+			*(*op)++ = 255;
+		*(*op)++ = (u8)len;
+	} else
+		*token = (length << ML_BITS);
+
+	/* Copy Literals */
+	LZ4_BLINDCOPY(*anchor, *op, length);
+
+	/* Encode Offset */
+	LZ4_WRITE_LITTLEENDIAN_16(*op, (u16)(*ip - ref));
+
+	/* Encode MatchLength */
+	len = (int)(ml - MINMATCH);
+	if (len >= (int)ML_MASK) {
+		*token += ML_MASK;
+		len -= ML_MASK;
+		for (; len > 509 ; len -= 510) {
+			*(*op)++ = 255;
+			*(*op)++ = 255;
+		}
+		if (len > 254) {
+			len -= 255;
+			*(*op)++ = 255;
+		}
+		*(*op)++ = (u8)len;
+	} else
+		*token += len;
+
+	/* Prepare next loop */
+	*ip += ml;
+	*anchor = *ip;
+
+	return 0;
+}
+
+static int lz4_compresshcctx(struct lz4hc_data *ctx,
+		const char *source,
+		char *dest,
+		int isize)
+{
+	const u8 *ip = (const u8 *)source;
+	const u8 *anchor = ip;
+	const u8 *const iend = ip + isize;
+	const u8 *const mflimit = iend - MFLIMIT;
+	const u8 *const matchlimit = (iend - LASTLITERALS);
+
+	u8 *op = (u8 *)dest;
+
+	int ml, ml2, ml3, ml0;
+	const u8 *ref = NULL;
+	const u8 *start2 = NULL;
+	const u8 *ref2 = NULL;
+	const u8 *start3 = NULL;
+	const u8 *ref3 = NULL;
+	const u8 *start0;
+	const u8 *ref0;
+	int lastrun;
+
+	ip++;
+
+	/* Main Loop */
+	while (ip < mflimit) {
+		ml = lz4hc_insertandfindbestmatch(ctx, ip, matchlimit, (&ref));
+		if (!ml) {
+			ip++;
+			continue;
+		}
+
+		/* saved, in case we would skip too much */
+		start0 = ip;
+		ref0 = ref;
+		ml0 = ml;
+_search2:
+		if (ip+ml < mflimit)
+			ml2 = lz4hc_insertandgetwidermatch(ctx, ip + ml - 2,
+				ip + 1, matchlimit, ml, &ref2, &start2);
+		else
+			ml2 = ml;
+		/* No better match */
+		if (ml2 == ml) {
+			lz4_encodesequence(&ip, &op, &anchor, ml, ref);
+			continue;
+		}
+
+		if (start0 < ip) {
+			/* empirical */
+			if (start2 < ip + ml0) {
+				ip = start0;
+				ref = ref0;
+				ml = ml0;
+			}
+		}
+		/*
+		 * Here, start0==ip
+		 * First Match too small : removed
+		 */
+		if ((start2 - ip) < 3) {
+			ml = ml2;
+			ip = start2;
+			ref = ref2;
+			goto _search2;
+		}
+
+_search3:
+		/*
+		 * Currently we have :
+		 * ml2 > ml1, and
+		 * ip1+3 <= ip2 (usually < ip1+ml1)
+		 */
+		if ((start2 - ip) < OPTIMAL_ML) {
+			int correction;
+			int new_ml = ml;
+			if (new_ml > OPTIMAL_ML)
+				new_ml = OPTIMAL_ML;
+			if (ip + new_ml > start2 + ml2 - MINMATCH)
+				new_ml = (int)(start2 - ip) + ml2 - MINMATCH;
+			correction = new_ml - (int)(start2 - ip);
+			if (correction > 0) {
+				start2 += correction;
+				ref2 += correction;
+				ml2 -= correction;
+			}
+		}
+		/*
+		 * Now, we have start2 = ip+new_ml,
+		 * with new_ml=min(ml, OPTIMAL_ML=18)
+		 */
+		if (start2 + ml2 < mflimit)
+			ml3 = lz4hc_insertandgetwidermatch(ctx,
+				start2 + ml2 - 3, start2, matchlimit,
+				ml2, &ref3, &start3);
+		else
+			ml3 = ml2;
+
+		/* No better match : 2 sequences to encode */
+		if (ml3 == ml2) {
+			/* ip & ref are known; Now for ml */
+			if (start2 < ip+ml)
+				ml = (int)(start2 - ip);
+
+			/* Now, encode 2 sequences */
+			lz4_encodesequence(&ip, &op, &anchor, ml, ref);
+			ip = start2;
+			lz4_encodesequence(&ip, &op, &anchor, ml2, ref2);
+			continue;
+		}
+
+		/* Not enough space for match 2 : remove it */
+		if (start3 < ip + ml + 3) {
+			/*
+			 * can write Seq1 immediately ==> Seq2 is removed,
+			 * so Seq3 becomes Seq1
+			 */
+			if (start3 >= (ip + ml)) {
+				if (start2 < ip + ml) {
+					int correction =
+						(int)(ip + ml - start2);
+					start2 += correction;
+					ref2 += correction;
+					ml2 -= correction;
+					if (ml2 < MINMATCH) {
+						start2 = start3;
+						ref2 = ref3;
+						ml2 = ml3;
+					}
+				}
+
+				lz4_encodesequence(&ip, &op, &anchor, ml, ref);
+				ip  = start3;
+				ref = ref3;
+				ml  = ml3;
+
+				start0 = start2;
+				ref0 = ref2;
+				ml0 = ml2;
+				goto _search2;
+			}
+
+			start2 = start3;
+			ref2 = ref3;
+			ml2 = ml3;
+			goto _search3;
+		}
+
+		/*
+		 * OK, now we have 3 ascending matches; let's write at least
+		 * the first one ip & ref are known; Now for ml
+		 */
+		if (start2 < ip + ml) {
+			if ((start2 - ip) < (int)ML_MASK) {
+				int correction;
+				if (ml > OPTIMAL_ML)
+					ml = OPTIMAL_ML;
+				if (ip + ml > start2 + ml2 - MINMATCH)
+					ml = (int)(start2 - ip) + ml2
+						- MINMATCH;
+				correction = ml - (int)(start2 - ip);
+				if (correction > 0) {
+					start2 += correction;
+					ref2 += correction;
+					ml2 -= correction;
+				}
+			} else
+				ml = (int)(start2 - ip);
+		}
+		lz4_encodesequence(&ip, &op, &anchor, ml, ref);
+
+		ip = start2;
+		ref = ref2;
+		ml = ml2;
+
+		start2 = start3;
+		ref2 = ref3;
+		ml2 = ml3;
+
+		goto _search3;
+	}
+
+	/* Encode Last Literals */
+	lastrun = (int)(iend - anchor);
+	if (lastrun >= (int)RUN_MASK) {
+		*op++ = (RUN_MASK << ML_BITS);
+		lastrun -= RUN_MASK;
+		for (; lastrun > 254 ; lastrun -= 255)
+			*op++ = 255;
+		*op++ = (u8) lastrun;
+	} else
+		*op++ = (lastrun << ML_BITS);
+	memcpy(op, anchor, iend - anchor);
+	op += iend - anchor;
+	/* End */
+	return (int) (((char *)op) - dest);
+}
+
+int lz4hc_compress(const unsigned char *src, size_t src_len,
+			unsigned char *dst, size_t *dst_len, void *wrkmem)
+{
+	int ret = -1;
+	int out_len = 0;
+
+	struct lz4hc_data *hc4 = (struct lz4hc_data *)wrkmem;
+	lz4hc_init(hc4, (const u8 *)src);
+	out_len = lz4_compresshcctx((struct lz4hc_data *)hc4, (const u8 *)src,
+		(char *)dst, (int)src_len);
+
+	if (out_len < 0)
+		goto exit;
+
+	*dst_len = out_len;
+	return 0;
+
+exit:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(lz4hc_compress);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZ4HC compressor");