kernel_3_2_10.patch

diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index 25cdff3..ace8395 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -88,6 +88,8 @@ source "drivers/staging/sep/Kconfig"
 
 source "drivers/staging/iio/Kconfig"
 
+source "drivers/staging/snappy/Kconfig"
+
 source "drivers/staging/zram/Kconfig"
 
 source "drivers/staging/zcache/Kconfig"
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index a25f3f2..2c0862b 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -57,3 +57,5 @@ obj-$(CONFIG_TOUCHSCREEN_SYNAPTICS_I2C_RMI4)	+= ste_rmi4/
 obj-$(CONFIG_DRM_PSB)		+= gma500/
 obj-$(CONFIG_INTEL_MEI)		+= mei/
 obj-$(CONFIG_MFD_NVEC)		+= nvec/
+obj-$(CONFIG_SNAPPY_COMPRESS)	+= snappy/
+obj-$(CONFIG_SNAPPY_DECOMPRESS)	+= snappy/
diff --git a/drivers/staging/snappy/Kconfig b/drivers/staging/snappy/Kconfig
new file mode 100644
index 0000000..24f6908
--- /dev/null
+++ b/drivers/staging/snappy/Kconfig
@@ -0,0 +1,5 @@
+config SNAPPY_COMPRESS
+	tristate "Google Snappy Compression"
+
+config SNAPPY_DECOMPRESS
+	tristate "Google Snappy Decompression"
diff --git a/drivers/staging/snappy/Makefile b/drivers/staging/snappy/Makefile
new file mode 100644
index 0000000..f5be21d
--- /dev/null
+++ b/drivers/staging/snappy/Makefile
@@ -0,0 +1,7 @@
+ccflags-y := -std=gnu99
+
+snappy_compress-objs := csnappy_compress.o
+snappy_decompress-objs := csnappy_decompress.o
+
+obj-$(CONFIG_SNAPPY_COMPRESS) += csnappy_compress.o
+obj-$(CONFIG_SNAPPY_DECOMPRESS) += csnappy_decompress.o
diff --git a/drivers/staging/snappy/csnappy.h b/drivers/staging/snappy/csnappy.h
new file mode 100644
index 0000000..97a3e17
--- /dev/null
+++ b/drivers/staging/snappy/csnappy.h
@@ -0,0 +1,129 @@
+#ifndef __CSNAPPY_H__
+#define __CSNAPPY_H__
+/*
+File modified for the Linux Kernel by
+Zeev Tarantov <zeev.tarantov@gmail.com>
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define CSNAPPY_VERSION	4
+
+#define CSNAPPY_WORKMEM_BYTES_POWER_OF_TWO 15
+#define CSNAPPY_WORKMEM_BYTES (1 << CSNAPPY_WORKMEM_BYTES_POWER_OF_TWO)
+
+#ifndef __GNUC__
+#define __attribute__(x) /*NOTHING*/
+#endif
+
+/*
+ * Returns the maximal size of the compressed representation of
+ * input data that is "source_len" bytes in length;
+ */
+uint32_t
+csnappy_max_compressed_length(uint32_t source_len) __attribute__((const));
+
+/*
+ * Flat array compression that does not emit the "uncompressed length"
+ * prefix. Compresses "input" array to the "output" array.
+ *
+ * REQUIRES: "input" is at most 32KiB long.
+ * REQUIRES: "output" points to an array of memory that is at least
+ * "csnappy_max_compressed_length(input_length)" in size.
+ * REQUIRES: working_memory has (1 << workmem_bytes_power_of_two) bytes.
+ * REQUIRES: 9 <= workmem_bytes_power_of_two <= 15.
+ *
+ * Returns an "end" pointer into "output" buffer.
+ * "end - output" is the compressed size of "input".
+ */
+char*
+csnappy_compress_fragment(
+	const char *input,
+	const uint32_t input_length,
+	char *output,
+	void *working_memory,
+	const int workmem_bytes_power_of_two);
+
+/*
+ * REQUIRES: "compressed" must point to an area of memory that is at
+ * least "csnappy_max_compressed_length(input_length)" bytes in length.
+ * REQUIRES: working_memory has (1 << workmem_bytes_power_of_two) bytes.
+ * REQUIRES: 9 <= workmem_bytes_power_of_two <= 15.
+ *
+ * Takes the data stored in "input[0..input_length]" and stores
+ * it in the array pointed to by "compressed".
+ *
+ * "*out_compressed_length" is set to the length of the compressed output.
+ */
+void
+csnappy_compress(
+	const char *input,
+	uint32_t input_length,
+	char *compressed,
+	uint32_t *out_compressed_length,
+	void *working_memory,
+	const int workmem_bytes_power_of_two);
+
+/*
+ * Reads header of compressed data to get stored length of uncompressed data.
+ * REQUIRES: start points to compressed data.
+ * REQUIRES: n is length of available compressed data.
+ *
+ * Returns SNAPPY_E_HEADER_BAD on error.
+ * Returns number of bytes read from input on success.
+ * Stores decoded length into *result.
+ */
+int
+csnappy_get_uncompressed_length(
+	const char *start,
+	uint32_t n,
+	uint32_t *result);
+
+/*
+ * Safely decompresses all data from array "src" of length "src_len" containing
+ * entire compressed stream (with header) into array "dst" of size "dst_len".
+ * REQUIRES: dst_len is at least csnappy_get_uncompressed_length(...).
+ *
+ * Iff successful, returns CSNAPPY_E_OK.
+ * If recorded length in header is greater than dst_len, returns
+ *  CSNAPPY_E_OUTPUT_INSUF.
+ * If compressed data is malformed, does not write more than dst_len into dst.
+ */
+int
+csnappy_decompress(
+	const char *src,
+	uint32_t src_len,
+	char *dst,
+	uint32_t dst_len);
+
+/*
+ * Safely decompresses stream src_len bytes long read from src to dst.
+ * Amount of available space at dst must be provided in *dst_len by caller.
+ * If compressed stream needs more space, it will not overflow and return
+ *  CSNAPPY_E_OUTPUT_OVERRUN.
+ * On success, sets *dst_len to actal number of bytes decompressed.
+ * Iff successful, returns CSNAPPY_E_OK.
+ */
+int
+csnappy_decompress_noheader(
+	const char *src,
+	uint32_t src_len,
+	char *dst,
+	uint32_t *dst_len);
+
+/*
+ * Return values (< 0 = Error)
+ */
+#define CSNAPPY_E_OK			0
+#define CSNAPPY_E_HEADER_BAD		(-1)
+#define CSNAPPY_E_OUTPUT_INSUF		(-2)
+#define CSNAPPY_E_OUTPUT_OVERRUN	(-3)
+#define CSNAPPY_E_INPUT_NOT_CONSUMED	(-4)
+#define CSNAPPY_E_DATA_MALFORMED	(-5)
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/drivers/staging/snappy/csnappy_compress.c b/drivers/staging/snappy/csnappy_compress.c
new file mode 100644
index 0000000..b093727
--- /dev/null
+++ b/drivers/staging/snappy/csnappy_compress.c
@@ -0,0 +1,527 @@
+/*
+Copyright 2011, Google Inc.
+All rights reserved.
+
+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.
+  * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+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.
+
+File modified for the Linux Kernel by
+Zeev Tarantov <zeev.tarantov@gmail.com>
+*/
+
+#include "csnappy_internal.h"
+#ifdef __KERNEL__
+#include <linux/kernel.h>
+#include <linux/module.h>
+#endif
+#include "csnappy.h"
+
+
+static inline char*
+encode_varint32(char *sptr, uint32_t v)
+{
+	uint8_t* ptr = (uint8_t *)sptr;
+	static const int B = 128;
+	if (v < (1<<7)) {
+		*(ptr++) = v;
+	} else if (v < (1<<14)) {
+		*(ptr++) = v | B;
+		*(ptr++) = v>>7;
+	} else if (v < (1<<21)) {
+		*(ptr++) = v | B;
+		*(ptr++) = (v>>7) | B;
+		*(ptr++) = v>>14;
+	} else if (v < (1<<28)) {
+		*(ptr++) = v | B;
+		*(ptr++) = (v>>7) | B;
+		*(ptr++) = (v>>14) | B;
+		*(ptr++) = v>>21;
+	} else {
+		*(ptr++) = v | B;
+		*(ptr++) = (v>>7) | B;
+		*(ptr++) = (v>>14) | B;
+		*(ptr++) = (v>>21) | B;
+		*(ptr++) = v>>28;
+	}
+	return (char *)ptr;
+}
+
+
+/*
+ * Any hash function will produce a valid compressed bitstream, but a good
+ * hash function reduces the number of collisions and thus yields better
+ * compression for compressible input, and more speed for incompressible
+ * input. Of course, it doesn't hurt if the hash function is reasonably fast
+ * either, as it gets called a lot.
+ */
+static inline uint32_t HashBytes(uint32_t bytes, int shift)
+{
+	uint32_t kMul = 0x1e35a7bd;
+	return (bytes * kMul) >> shift;
+}
+static inline uint32_t Hash(const char *p, int shift)
+{
+	return HashBytes(UNALIGNED_LOAD32(p), shift);
+}
+
+
+/*
+ * *** DO NOT CHANGE THE VALUE OF kBlockSize ***
+
+ * New Compression code chops up the input into blocks of at most
+ * the following size.  This ensures that back-references in the
+ * output never cross kBlockSize block boundaries.  This can be
+ * helpful in implementing blocked decompression.  However the
+ * decompression code should not rely on this guarantee since older
+ * compression code may not obey it.
+ */
+#define kBlockLog 15
+#define kBlockSize (1 << kBlockLog)
+
+
+/*
+ * Return the largest n such that
+ *
+ *   s1[0,n-1] == s2[0,n-1]
+ *   and n <= (s2_limit - s2).
+ *
+ * Does not read *s2_limit or beyond.
+ * Does not read *(s1 + (s2_limit - s2)) or beyond.
+ * Requires that s2_limit >= s2.
+ *
+ * Separate implementation for x86_64, for speed.  Uses the fact that
+ * x86_64 is little endian.
+ */
+#if defined(__x86_64__)
+static inline int
+FindMatchLength(const char *s1, const char *s2, const char *s2_limit)
+{
+	uint64_t x;
+	int matched, matching_bits;
+	DCHECK_GE(s2_limit, s2);
+	matched = 0;
+	/*
+	 * Find out how long the match is. We loop over the data 64 bits at a
+	 * time until we find a 64-bit block that doesn't match; then we find
+	 * the first non-matching bit and use that to calculate the total
+	 * length of the match.
+	 */
+	while (likely(s2 <= s2_limit - 8)) {
+		if (unlikely(UNALIGNED_LOAD64(s1 + matched) ==
+				UNALIGNED_LOAD64(s2))) {
+			s2 += 8;
+			matched += 8;
+		} else {
+			/*
+			 * On current (mid-2008) Opteron models there is a 3%
+			 * more efficient code sequence to find the first
+			 * non-matching byte. However, what follows is ~10%
+			 * better on Intel Core 2 and newer, and we expect AMD's
+			 * bsf instruction to improve.
+			 */
+			x = UNALIGNED_LOAD64(s1 + matched) ^
+				UNALIGNED_LOAD64(s2);
+			matching_bits = FindLSBSetNonZero64(x);
+			matched += matching_bits >> 3;
+			return matched;
+		}
+	}
+	while (likely(s2 < s2_limit)) {
+		if (likely(s1[matched] == *s2)) {
+			++s2;
+			++matched;
+		} else {
+			return matched;
+		}
+	}
+	return matched;
+}
+#else /* !defined(__x86_64__) */
+static inline int
+FindMatchLength(const char *s1, const char *s2, const char *s2_limit)
+{
+	/* Implementation based on the x86-64 version, above. */
+	int matched = 0;
+	DCHECK_GE(s2_limit, s2);
+
+	while (s2 <= s2_limit - 4 &&
+		UNALIGNED_LOAD32(s2) == UNALIGNED_LOAD32(s1 + matched)) {
+		s2 += 4;
+		matched += 4;
+	}
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+	if (s2 <= s2_limit - 4) {
+		uint32_t x = UNALIGNED_LOAD32(s1 + matched) ^
+				UNALIGNED_LOAD32(s2);
+		int matching_bits = FindLSBSetNonZero(x);
+		matched += matching_bits >> 3;
+	} else {
+		while ((s2 < s2_limit) && (s1[matched] == *s2)) {
+			++s2;
+			++matched;
+		}
+	}
+#else
+	while ((s2 < s2_limit) && (s1[matched] == *s2)) {
+		++s2;
+		++matched;
+	}
+#endif
+	return matched;
+}
+#endif /* !defined(__x86_64__) */
+
+
+static inline char*
+EmitLiteral(char *op, const char *literal, int len, int allow_fast_path)
+{
+	int n = len - 1; /* Zero-length literals are disallowed */
+	if (n < 60) {
+		/* Fits in tag byte */
+		*op++ = LITERAL | (n << 2);
+		/*
+		The vast majority of copies are below 16 bytes, for which a
+		call to memcpy is overkill. This fast path can sometimes
+		copy up to 15 bytes too much, but that is okay in the
+		main loop, since we have a bit to go on for both sides:
+		- The input will always have kInputMarginBytes = 15 extra
+		available bytes, as long as we're in the main loop, and
+		if not, allow_fast_path = false.
+		- The output will always have 32 spare bytes (see
+		snappy_max_compressed_length).
+		*/
+		if (allow_fast_path && len <= 16) {
+			UnalignedCopy64(literal, op);
+			UnalignedCopy64(literal + 8, op + 8);
+			return op + len;
+		}
+	} else {
+		/* Encode in upcoming bytes */
+		char *base = op;
+		int count = 0;
+		op++;
+		while (n > 0) {
+			*op++ = n & 0xff;
+			n >>= 8;
+			count++;
+		}
+		DCHECK_GE(count, 1);
+		DCHECK_LE(count, 4);
+		*base = LITERAL | ((59+count) << 2);
+	}
+	memcpy(op, literal, len);
+	return op + len;
+}
+
+static inline char*
+EmitCopyLessThan64(char *op, int offset, int len)
+{
+	DCHECK_LE(len, 64);
+	DCHECK_GE(len, 4);
+	DCHECK_LT(offset, 65536);
+
+	if ((len < 12) && (offset < 2048)) {
+		int len_minus_4 = len - 4;
+		DCHECK_LT(len_minus_4, 8); /* Must fit in 3 bits */
+		*op++ = COPY_1_BYTE_OFFSET   |
+			((len_minus_4) << 2) |
+			((offset >> 8) << 5);
+		*op++ = offset & 0xff;
+	} else {
+		*op++ = COPY_2_BYTE_OFFSET | ((len-1) << 2);
+		put_unaligned_le16(offset, op);
+		op += 2;
+	}
+	return op;
+}
+
+static inline char*
+EmitCopy(char *op, int offset, int len)
+{
+	/* Emit 64 byte copies but make sure to keep at least four bytes
+	 * reserved */
+	while (len >= 68) {
+		op = EmitCopyLessThan64(op, offset, 64);
+		len -= 64;
+	}
+
+	/* Emit an extra 60 byte copy if have too much data to fit in one
+	 * copy */
+	if (len > 64) {
+		op = EmitCopyLessThan64(op, offset, 60);
+		len -= 60;
+	}
+
+	/* Emit remainder */
+	op = EmitCopyLessThan64(op, offset, len);
+	return op;
+}
+
+
+/*
+For 0 <= offset <= 4, GetUint32AtOffset(GetEightBytesAt(p), offset) will
+equal UNALIGNED_LOAD32(p + offset).  Motivation: On x86-64 hardware we have
+empirically found that overlapping loads such as
+ UNALIGNED_LOAD32(p) ... UNALIGNED_LOAD32(p+1) ... UNALIGNED_LOAD32(p+2)
+are slower than UNALIGNED_LOAD64(p) followed by shifts and casts to uint32.
+
+We have different versions for 64- and 32-bit; ideally we would avoid the
+two functions and just inline the UNALIGNED_LOAD64 call into
+GetUint32AtOffset, but GCC (at least not as of 4.6) is seemingly not clever
+enough to avoid loading the value multiple times then. For 64-bit, the load
+is done when GetEightBytesAt() is called, whereas for 32-bit, the load is
+done at GetUint32AtOffset() time.
+*/
+
+#if defined(__x86_64__) || (__SIZEOF_SIZE_T__ == 8)
+
+typedef uint64_t EightBytesReference;
+
+static inline EightBytesReference GetEightBytesAt(const char* ptr) {
+	return UNALIGNED_LOAD64(ptr);
+}
+
+static inline uint32_t GetUint32AtOffset(uint64_t v, int offset) {
+	DCHECK_GE(offset, 0);
+	DCHECK_LE(offset, 4);
+#ifdef __LITTLE_ENDIAN
+	return v >> (8 * offset);
+#else
+	return v >> (32 - 8 * offset);
+#endif
+}
+
+#else /* !ARCH_K8 */
+
+typedef const char* EightBytesReference;
+
+static inline EightBytesReference GetEightBytesAt(const char* ptr) {
+	return ptr;
+}
+
+static inline uint32_t GetUint32AtOffset(const char* v, int offset) {
+	DCHECK_GE(offset, 0);
+	DCHECK_LE(offset, 4);
+	return UNALIGNED_LOAD32(v + offset);
+}
+
+#endif /* !ARCH_K8 */
+
+
+#define kInputMarginBytes 15
+char*
+csnappy_compress_fragment(
+	const char *input,
+	const uint32_t input_size,
+	char *op,
+	void *working_memory,
+	const int workmem_bytes_power_of_two)
+{
+	const char *ip, *ip_end, *base_ip, *next_emit, *ip_limit, *next_ip,
+			*candidate, *base;
+	uint16_t *table = (uint16_t *)working_memory;
+	EightBytesReference input_bytes;
+	uint32_t hash, next_hash, prev_hash, cur_hash, skip, candidate_bytes;
+	int shift, matched;
+
+	DCHECK_GE(workmem_bytes_power_of_two, 9);
+	DCHECK_LE(workmem_bytes_power_of_two, 15);
+	/* Table of 2^X bytes, need (X-1) bits to address table of uint16_t.
+	 * How many bits of 32bit hash function result are discarded? */
+	shift = 33 - workmem_bytes_power_of_two;
+	/* "ip" is the input pointer, and "op" is the output pointer. */
+	ip = input;
+	DCHECK_LE(input_size, kBlockSize);
+	ip_end = input + input_size;
+	base_ip = ip;
+	/* Bytes in [next_emit, ip) will be emitted as literal bytes. Or
+	   [next_emit, ip_end) after the main loop. */
+	next_emit = ip;
+
+	if (unlikely(input_size < kInputMarginBytes))
+		goto emit_remainder;
+
+	memset(working_memory, 0, 1 << workmem_bytes_power_of_two);
+
+	ip_limit = input + input_size - kInputMarginBytes;
+	next_hash = Hash(++ip, shift);
+
+main_loop:
+	DCHECK_LT(next_emit, ip);
+	/*
+	* The body of this loop calls EmitLiteral once and then EmitCopy one or
+	* more times. (The exception is that when we're close to exhausting
+	* the input we goto emit_remainder.)
+	*
+	* In the first iteration of this loop we're just starting, so
+	* there's nothing to copy, so calling EmitLiteral once is
+	* necessary. And we only start a new iteration when the
+	* current iteration has determined that a call to EmitLiteral will
+	* precede the next call to EmitCopy (if any).
+	*
+	* Step 1: Scan forward in the input looking for a 4-byte-long match.
+	* If we get close to exhausting the input then goto emit_remainder.
+	*
+	* Heuristic match skipping: If 32 bytes are scanned with no matches
+	* found, start looking only at every other byte. If 32 more bytes are
+	* scanned, look at every third byte, etc.. When a match is found,
+	* immediately go back to looking at every byte. This is a small loss
+	* (~5% performance, ~0.1% density) for compressible data due to more
+	* bookkeeping, but for non-compressible data (such as JPEG) it's a huge
+	* win since the compressor quickly "realizes" the data is incompressible
+	* and doesn't bother looking for matches everywhere.
+	*
+	* The "skip" variable keeps track of how many bytes there are since the
+	* last match; dividing it by 32 (ie. right-shifting by five) gives the
+	* number of bytes to move ahead for each iteration.
+	*/
+	skip = 32;
+
+	next_ip = ip;
+	do {
+		ip = next_ip;
+		hash = next_hash;
+		DCHECK_EQ(hash, Hash(ip, shift));
+		next_ip = ip + (skip++ >> 5);
+		if (unlikely(next_ip > ip_limit))
+			goto emit_remainder;
+		next_hash = Hash(next_ip, shift);
+		candidate = base_ip + table[hash];
+		DCHECK_GE(candidate, base_ip);
+		DCHECK_LT(candidate, ip);
+
+		table[hash] = ip - base_ip;
+	} while (likely(UNALIGNED_LOAD32(ip) !=
+			UNALIGNED_LOAD32(candidate)));
+
+	/*
+	* Step 2: A 4-byte match has been found. We'll later see if more
+	* than 4 bytes match. But, prior to the match, input
+	* bytes [next_emit, ip) are unmatched. Emit them as "literal bytes."
+	*/
+	DCHECK_LE(next_emit + 16, ip_end);
+	op = EmitLiteral(op, next_emit, ip - next_emit, 1);
+
+	/*
+	* Step 3: Call EmitCopy, and then see if another EmitCopy could
+	* be our next move. Repeat until we find no match for the
+	* input immediately after what was consumed by the last EmitCopy call.
+	*
+	* If we exit this loop normally then we need to call EmitLiteral next,
+	* though we don't yet know how big the literal will be. We handle that
+	* by proceeding to the next iteration of the main loop. We also can exit
+	* this loop via goto if we get close to exhausting the input.
+	*/
+	candidate_bytes = 0;
+
+	do {
+		/* We have a 4-byte match at ip, and no need to emit any
+		 "literal bytes" prior to ip. */
+		base = ip;
+		matched = 4 + FindMatchLength(candidate + 4, ip + 4, ip_end);
+		ip += matched;
+		DCHECK_EQ(0, memcmp(base, candidate, matched));
+		op = EmitCopy(op, base - candidate, matched);
+		/* We could immediately start working at ip now, but to improve
+		 compression we first update table[Hash(ip - 1, ...)]. */
+		next_emit = ip;
+		if (unlikely(ip >= ip_limit))
+			goto emit_remainder;
+		input_bytes = GetEightBytesAt(ip - 1);
+		prev_hash = HashBytes(GetUint32AtOffset(input_bytes, 0), shift);
+		table[prev_hash] = ip - base_ip - 1;
+		cur_hash = HashBytes(GetUint32AtOffset(input_bytes, 1), shift);
+		candidate = base_ip + table[cur_hash];
+		candidate_bytes = UNALIGNED_LOAD32(candidate);
+		table[cur_hash] = ip - base_ip;
+	} while (GetUint32AtOffset(input_bytes, 1) == candidate_bytes);
+
+	next_hash = HashBytes(GetUint32AtOffset(input_bytes, 2), shift);
+	++ip;
+	goto main_loop;
+
+emit_remainder:
+	/* Emit the remaining bytes as a literal */
+	if (next_emit < ip_end)
+		op = EmitLiteral(op, next_emit, ip_end - next_emit, 0);
+
+	return op;
+}
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_compress_fragment);
+#endif
+
+uint32_t __attribute__((const))
+csnappy_max_compressed_length(uint32_t source_len)
+{
+	return 32 + source_len + source_len/6;
+}
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_max_compressed_length);
+#endif
+
+void
+csnappy_compress(
+	const char *input,
+	uint32_t input_length,
+	char *compressed,
+	uint32_t *compressed_length,
+	void *working_memory,
+	const int workmem_bytes_power_of_two)
+{
+	int workmem_size;
+	int num_to_read;
+	uint32_t written = 0;
+	char *p = encode_varint32(compressed, input_length);
+	written += (p - compressed);
+	compressed = p;
+	while (input_length > 0) {
+		num_to_read = min(input_length, (uint32_t)kBlockSize);
+		workmem_size = workmem_bytes_power_of_two;
+		if (num_to_read < kBlockSize) {
+			for (workmem_size = 9;
+			     workmem_size < workmem_bytes_power_of_two;
+			     ++workmem_size) {
+				if ((1 << (workmem_size-1)) >= num_to_read)
+					break;
+			}
+		}
+		p = csnappy_compress_fragment(
+				input, num_to_read, compressed,
+				working_memory, workmem_size);
+		written += (p - compressed);
+		compressed = p;
+		input_length -= num_to_read;
+		input += num_to_read;
+	}
+	*compressed_length = written;
+}
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_compress);
+
+MODULE_LICENSE("BSD");
+MODULE_DESCRIPTION("Snappy Compressor");
+#endif
diff --git a/drivers/staging/snappy/csnappy_decompress.c b/drivers/staging/snappy/csnappy_decompress.c
new file mode 100644
index 0000000..572ce43
--- /dev/null
+++ b/drivers/staging/snappy/csnappy_decompress.c
@@ -0,0 +1,413 @@
+/*
+Copyright 2011, Google Inc.
+All rights reserved.
+
+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.
+  * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+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.
+
+File modified for the Linux Kernel by
+Zeev Tarantov <zeev.tarantov@gmail.com>
+*/
+
+#include "csnappy_internal.h"
+#ifdef __KERNEL__
+#include <linux/kernel.h>
+#include <linux/module.h>
+#endif
+#include "csnappy.h"
+
+int
+csnappy_get_uncompressed_length(
+	const char *src,
+	uint32_t src_len,
+	uint32_t *result)
+{
+	const char *src_base = src;
+	uint32_t shift = 0;
+	uint8_t c;
+	/* Length is encoded in 1..5 bytes */
+	*result = 0;
+	for (;;) {
+		if (shift >= 32)
+			goto err_out;
+		if (src_len == 0)
+			goto err_out;
+		c = *(const uint8_t *)src++;
+		src_len -= 1;
+		*result |= (uint32_t)(c & 0x7f) << shift;
+		if (c < 128)
+			break;
+		shift += 7;
+	}
+	return src - src_base;
+err_out:
+	return CSNAPPY_E_HEADER_BAD;
+}
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_get_uncompressed_length);
+#endif
+
+#if defined(__arm__) && !(ARCH_ARM_HAVE_UNALIGNED)
+int csnappy_decompress_noheader(
+	const char	*src_,
+	uint32_t	src_remaining,
+	char		*dst,
+	uint32_t	*dst_len)
+{
+	const uint8_t * src = (const uint8_t *)src_;
+	const uint8_t * const src_end = src + src_remaining;
+	char * const dst_base = dst;
+	char * const dst_end = dst + *dst_len;
+	while (src < src_end) {
+		uint32_t opcode = *src++;
+		uint32_t length = (opcode >> 2) + 1;
+		const uint8_t *copy_src;
+		if (likely((opcode & 3) == 0)) {
+			if (unlikely(length > 60)) {
+				uint32_t extra_bytes = length - 60;
+				if (unlikely(src + extra_bytes > src_end))
+					return CSNAPPY_E_DATA_MALFORMED;
+				length = 0;
+				for (int shift = 0, max_shift = extra_bytes*8;
+					shift < max_shift;
+					shift += 8)
+					length |= *src++ << shift;
+				++length;
+			}
+			if (unlikely(src + length > src_end))
+				return CSNAPPY_E_DATA_MALFORMED;
+			copy_src = src;
+			src += length;
+		} else {
+			uint32_t offset;
+			if (likely((opcode & 3) == 1)) {
+				if (unlikely(src + 1 > src_end))
+					return CSNAPPY_E_DATA_MALFORMED;
+				length = ((length - 1) & 7) + 4;
+				offset = ((opcode >> 5) << 8) + *src++;
+			} else if (likely((opcode & 3) == 2)) {
+				if (unlikely(src + 2 > src_end))
+					return CSNAPPY_E_DATA_MALFORMED;
+				offset = src[0] | (src[1] << 8);
+				src += 2;
+			} else {
+				if (unlikely(src + 4 > src_end))
+					return CSNAPPY_E_DATA_MALFORMED;
+				offset = src[0] | (src[1] << 8) |
+					 (src[2] << 16) | (src[3] << 24);
+				src += 4;
+			}
+			if (unlikely(!offset || (offset > dst - dst_base)))
+				return CSNAPPY_E_DATA_MALFORMED;
+			copy_src = (const uint8_t *)dst - offset;
+		}
+		if (unlikely(dst + length > dst_end))
+			return CSNAPPY_E_OUTPUT_OVERRUN;
+		do *dst++ = *copy_src++; while (--length);
+	}
+	*dst_len = dst - dst_base;
+	return CSNAPPY_E_OK;
+}
+#else /* !(arm with no unaligned access) */
+/*
+ * Data stored per entry in lookup table:
+ *      Range   Bits-used       Description
+ *      ------------------------------------
+ *      1..64   0..7            Literal/copy length encoded in opcode byte
+ *      0..7    8..10           Copy offset encoded in opcode byte / 256
+ *      0..4    11..13          Extra bytes after opcode
+ *
+ * We use eight bits for the length even though 7 would have sufficed
+ * because of efficiency reasons:
+ *      (1) Extracting a byte is faster than a bit-field
+ *      (2) It properly aligns copy offset so we do not need a <<8
+ */
+static const uint16_t char_table[256] = {
+	0x0001, 0x0804, 0x1001, 0x2001, 0x0002, 0x0805, 0x1002, 0x2002,
+	0x0003, 0x0806, 0x1003, 0x2003, 0x0004, 0x0807, 0x1004, 0x2004,
+	0x0005, 0x0808, 0x1005, 0x2005, 0x0006, 0x0809, 0x1006, 0x2006,
+	0x0007, 0x080a, 0x1007, 0x2007, 0x0008, 0x080b, 0x1008, 0x2008,
+	0x0009, 0x0904, 0x1009, 0x2009, 0x000a, 0x0905, 0x100a, 0x200a,
+	0x000b, 0x0906, 0x100b, 0x200b, 0x000c, 0x0907, 0x100c, 0x200c,
+	0x000d, 0x0908, 0x100d, 0x200d, 0x000e, 0x0909, 0x100e, 0x200e,
+	0x000f, 0x090a, 0x100f, 0x200f, 0x0010, 0x090b, 0x1010, 0x2010,
+	0x0011, 0x0a04, 0x1011, 0x2011, 0x0012, 0x0a05, 0x1012, 0x2012,
+	0x0013, 0x0a06, 0x1013, 0x2013, 0x0014, 0x0a07, 0x1014, 0x2014,
+	0x0015, 0x0a08, 0x1015, 0x2015, 0x0016, 0x0a09, 0x1016, 0x2016,
+	0x0017, 0x0a0a, 0x1017, 0x2017, 0x0018, 0x0a0b, 0x1018, 0x2018,
+	0x0019, 0x0b04, 0x1019, 0x2019, 0x001a, 0x0b05, 0x101a, 0x201a,
+	0x001b, 0x0b06, 0x101b, 0x201b, 0x001c, 0x0b07, 0x101c, 0x201c,
+	0x001d, 0x0b08, 0x101d, 0x201d, 0x001e, 0x0b09, 0x101e, 0x201e,
+	0x001f, 0x0b0a, 0x101f, 0x201f, 0x0020, 0x0b0b, 0x1020, 0x2020,
+	0x0021, 0x0c04, 0x1021, 0x2021, 0x0022, 0x0c05, 0x1022, 0x2022,
+	0x0023, 0x0c06, 0x1023, 0x2023, 0x0024, 0x0c07, 0x1024, 0x2024,
+	0x0025, 0x0c08, 0x1025, 0x2025, 0x0026, 0x0c09, 0x1026, 0x2026,
+	0x0027, 0x0c0a, 0x1027, 0x2027, 0x0028, 0x0c0b, 0x1028, 0x2028,
+	0x0029, 0x0d04, 0x1029, 0x2029, 0x002a, 0x0d05, 0x102a, 0x202a,
+	0x002b, 0x0d06, 0x102b, 0x202b, 0x002c, 0x0d07, 0x102c, 0x202c,
+	0x002d, 0x0d08, 0x102d, 0x202d, 0x002e, 0x0d09, 0x102e, 0x202e,
+	0x002f, 0x0d0a, 0x102f, 0x202f, 0x0030, 0x0d0b, 0x1030, 0x2030,
+	0x0031, 0x0e04, 0x1031, 0x2031, 0x0032, 0x0e05, 0x1032, 0x2032,
+	0x0033, 0x0e06, 0x1033, 0x2033, 0x0034, 0x0e07, 0x1034, 0x2034,
+	0x0035, 0x0e08, 0x1035, 0x2035, 0x0036, 0x0e09, 0x1036, 0x2036,
+	0x0037, 0x0e0a, 0x1037, 0x2037, 0x0038, 0x0e0b, 0x1038, 0x2038,
+	0x0039, 0x0f04, 0x1039, 0x2039, 0x003a, 0x0f05, 0x103a, 0x203a,
+	0x003b, 0x0f06, 0x103b, 0x203b, 0x003c, 0x0f07, 0x103c, 0x203c,
+	0x0801, 0x0f08, 0x103d, 0x203d, 0x1001, 0x0f09, 0x103e, 0x203e,
+	0x1801, 0x0f0a, 0x103f, 0x203f, 0x2001, 0x0f0b, 0x1040, 0x2040
+};
+
+/*
+ * Copy "len" bytes from "src" to "op", one byte at a time.  Used for
+ * handling COPY operations where the input and output regions may
+ * overlap.  For example, suppose:
+ *    src    == "ab"
+ *    op     == src + 2
+ *    len    == 20
+ * After IncrementalCopy(src, op, len), the result will have
+ * eleven copies of "ab"
+ *    ababababababababababab
+ * Note that this does not match the semantics of either memcpy()
+ * or memmove().
+ */
+static inline void IncrementalCopy(const char *src, char *op, int len)
+{
+	DCHECK_GT(len, 0);
+	do {
+		*op++ = *src++;
+	} while (--len > 0);
+}
+
+/*
+ * Equivalent to IncrementalCopy except that it can write up to ten extra
+ * bytes after the end of the copy, and that it is faster.
+ *
+ * The main part of this loop is a simple copy of eight bytes at a time until
+ * we've copied (at least) the requested amount of bytes.  However, if op and
+ * src are less than eight bytes apart (indicating a repeating pattern of
+ * length < 8), we first need to expand the pattern in order to get the correct
+ * results. For instance, if the buffer looks like this, with the eight-byte
+ * <src> and <op> patterns marked as intervals:
+ *
+ *    abxxxxxxxxxxxx
+ *    [------]           src
+ *      [------]         op
+ *
+ * a single eight-byte copy from <src> to <op> will repeat the pattern once,
+ * after which we can move <op> two bytes without moving <src>:
+ *
+ *    ababxxxxxxxxxx
+ *    [------]           src
+ *        [------]       op
+ *
+ * and repeat the exercise until the two no longer overlap.
+ *
+ * This allows us to do very well in the special case of one single byte
+ * repeated many times, without taking a big hit for more general cases.
+ *
+ * The worst case of extra writing past the end of the match occurs when
+ * op - src == 1 and len == 1; the last copy will read from byte positions
+ * [0..7] and write to [4..11], whereas it was only supposed to write to
+ * position 1. Thus, ten excess bytes.
+ */
+static const int kMaxIncrementCopyOverflow = 10;
+static inline void IncrementalCopyFastPath(const char *src, char *op, int len)
+{
+	while (op - src < 8) {
+		UnalignedCopy64(src, op);
+		len -= op - src;
+		op += op - src;
+	}
+	while (len > 0) {
+		UnalignedCopy64(src, op);
+		src += 8;
+		op += 8;
+		len -= 8;
+	}
+}
+
+
+/* A type that writes to a flat array. */
+struct SnappyArrayWriter {
+	char *base;
+	char *op;
+	char *op_limit;
+};
+
+static inline int
+SAW__AppendFastPath(struct SnappyArrayWriter *this,
+		    const char *ip, uint32_t len)
+{
+	char *op = this->op;
+	const int space_left = this->op_limit - op;
+	if (likely(space_left >= 16)) {
+		UnalignedCopy64(ip, op);
+		UnalignedCopy64(ip + 8, op + 8);
+	} else {
+		if (unlikely(space_left < len))
+			return CSNAPPY_E_OUTPUT_OVERRUN;
+		memcpy(op, ip, len);
+	}
+	this->op = op + len;
+	return CSNAPPY_E_OK;
+}
+
+static inline int
+SAW__Append(struct SnappyArrayWriter *this,
+	    const char *ip, uint32_t len)
+{
+	char *op = this->op;
+	const int space_left = this->op_limit - op;
+	if (unlikely(space_left < len))
+		return CSNAPPY_E_OUTPUT_OVERRUN;
+	memcpy(op, ip, len);
+	this->op = op + len;
+	return CSNAPPY_E_OK;
+}
+
+static inline int
+SAW__AppendFromSelf(struct SnappyArrayWriter *this,
+		    uint32_t offset, uint32_t len)
+{
+	char *op = this->op;
+	const int space_left = this->op_limit - op;
+	/* -1u catches offset==0 */
+	if (op - this->base <= offset - 1u)
+		return CSNAPPY_E_DATA_MALFORMED;
+	/* Fast path, used for the majority (70-80%) of dynamic invocations. */
+	if (len <= 16 && offset >= 8 && space_left >= 16) {
+		UnalignedCopy64(op - offset, op);
+		UnalignedCopy64(op - offset + 8, op + 8);
+	} else if (space_left >= len + kMaxIncrementCopyOverflow) {
+		IncrementalCopyFastPath(op - offset, op, len);
+	} else {
+		if (space_left < len)
+			return CSNAPPY_E_OUTPUT_OVERRUN;
+		IncrementalCopy(op - offset, op, len);
+	}
+	this->op = op + len;
+	return CSNAPPY_E_OK;
+}
+
+int
+csnappy_decompress_noheader(
+	const char	*src,
+	uint32_t	src_remaining,
+	char		*dst,
+	uint32_t	*dst_len)
+{
+	struct SnappyArrayWriter writer;
+	const char *end_minus5 = src + src_remaining - 5;
+	uint32_t length, trailer, opword, extra_bytes;
+	int ret, available;
+	uint8_t opcode;
+	char scratch[5];
+	writer.op = writer.base = dst;
+	writer.op_limit = writer.op + *dst_len;
+	#define LOOP_COND() \
+	if (unlikely(src >= end_minus5)) {		\
+		available = end_minus5 + 5 - src;	\
+		if (unlikely(available <= 0))		\
+			goto out;			\
+		memmove(scratch, src, available);	\
+		src = scratch;				\
+		end_minus5 = scratch + available - 5;	\
+	}
+	
+	LOOP_COND();
+	for (;;) {
+		opcode = *(const uint8_t *)src++;
+		if (opcode & 0x3) {
+			opword = char_table[opcode];
+			extra_bytes = opword >> 11;
+			trailer = get_unaligned_le(src, extra_bytes);
+			length = opword & 0xff;
+			src += extra_bytes;
+			trailer += opword & 0x700;
+			ret = SAW__AppendFromSelf(&writer, trailer, length);
+			if (ret < 0)
+				return ret;
+			LOOP_COND();
+		} else {
+			length = (opcode >> 2) + 1;
+			available = end_minus5 + 5 - src;
+			if (length <= 16 && available >= 16) {
+				if ((ret = SAW__AppendFastPath(&writer, src, length)) < 0)
+					return ret;
+				src += length;
+				LOOP_COND();
+				continue;
+			}
+			if (unlikely(length > 60)) {
+				extra_bytes = length - 60;
+				length = get_unaligned_le(src, extra_bytes) + 1;
+				src += extra_bytes;
+				available = end_minus5 + 5 - src;
+			}
+			if (unlikely(available < length))
+				return CSNAPPY_E_DATA_MALFORMED;
+			ret = SAW__Append(&writer, src, length);
+			if (ret < 0)
+				return ret;
+			src += length;
+			LOOP_COND();
+		}
+	}
+#undef LOOP_COND
+out:
+	*dst_len = writer.op - writer.base;
+	return CSNAPPY_E_OK;
+}
+#endif /* optimized for unaligned arch */
+
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_decompress_noheader);
+#endif
+
+int
+csnappy_decompress(
+	const char *src,
+	uint32_t src_len,
+	char *dst,
+	uint32_t dst_len)
+{
+	int n;
+	uint32_t olen = 0;
+	/* Read uncompressed length from the front of the compressed input */
+	n = csnappy_get_uncompressed_length(src, src_len, &olen);
+	if (unlikely(n < CSNAPPY_E_OK))
+		return n;
+	/* Protect against possible DoS attack */
+	if (unlikely(olen > dst_len))
+		return CSNAPPY_E_OUTPUT_INSUF;
+	return csnappy_decompress_noheader(src + n, src_len - n, dst, &olen);
+}
+#if defined(__KERNEL__) && !defined(STATIC)
+EXPORT_SYMBOL(csnappy_decompress);
+
+MODULE_LICENSE("BSD");
+MODULE_DESCRIPTION("Snappy Decompressor");
+#endif
diff --git a/drivers/staging/snappy/csnappy_internal.h b/drivers/staging/snappy/csnappy_internal.h
new file mode 100644
index 0000000..5fc7ba1
--- /dev/null
+++ b/drivers/staging/snappy/csnappy_internal.h
@@ -0,0 +1,147 @@
+/*
+Copyright 2011 Google Inc. All Rights Reserved.
+
+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.
+    * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+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.
+
+Various stubs for the open-source version of Snappy.
+
+File modified for the Linux Kernel by
+Zeev Tarantov <zeev.tarantov@gmail.com>
+*/
+
+#ifndef CSNAPPY_INTERNAL_H_
+#define CSNAPPY_INTERNAL_H_
+
+#ifndef __KERNEL__
+#include "csnappy_internal_userspace.h"
+#include <string.h>
+#else
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/compiler.h>
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+#if (defined(__LITTLE_ENDIAN) && defined(__BIG_ENDIAN)) || \
+    (!defined(__LITTLE_ENDIAN) && !defined(__BIG_ENDIAN))
+#error either __LITTLE_ENDIAN or __BIG_ENDIAN must be defined
+#endif
+#if defined(__LITTLE_ENDIAN)
+#define __BYTE_ORDER __LITTLE_ENDIAN
+#else
+#define __BYTE_ORDER __BIG_ENDIAN
+#endif
+
+#ifdef DEBUG
+#define DCHECK(cond)	if (!(cond)) \
+			printk(KERN_DEBUG "assert failed @ %s:%i\n", \
+				__FILE__, __LINE__)
+#else
+#define DCHECK(cond)
+#endif
+
+#define UNALIGNED_LOAD16(_p)		get_unaligned((const uint16_t *)(_p))
+#define UNALIGNED_LOAD32(_p)		get_unaligned((const uint32_t *)(_p))
+#define UNALIGNED_LOAD64(_p)		get_unaligned((const uint64_t *)(_p))
+#define UNALIGNED_STORE16(_p, _val)	put_unaligned((_val), (uint16_t *)(_p))
+#define UNALIGNED_STORE32(_p, _val)	put_unaligned((_val), (uint32_t *)(_p))
+#define UNALIGNED_STORE64(_p, _val)	put_unaligned((_val), (uint64_t *)(_p))
+
+#define FindLSBSetNonZero(n)		__builtin_ctz(n)
+#define FindLSBSetNonZero64(n)		__builtin_ctzll(n)
+
+#endif /* __KERNEL__ */
+
+#define ARCH_ARM_HAVE_UNALIGNED \
+    defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) || defined(__ARMV6__) || \
+    defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__)
+
+static inline void UnalignedCopy64(const void *src, void *dst) {
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__) || ARCH_ARM_HAVE_UNALIGNED
+  if ((sizeof(void *) == 8) || (sizeof(long) == 8)) {
+    UNALIGNED_STORE64(dst, UNALIGNED_LOAD64(src));
+  } else {
+   /* This can be more efficient than UNALIGNED_LOAD64 + UNALIGNED_STORE64
+      on some platforms, in particular ARM. */
+    const uint8_t *src_bytep = (const uint8_t *)src;
+    uint8_t *dst_bytep = (uint8_t *)dst;
+
+    UNALIGNED_STORE32(dst_bytep, UNALIGNED_LOAD32(src_bytep));
+    UNALIGNED_STORE32(dst_bytep + 4, UNALIGNED_LOAD32(src_bytep + 4));
+  }
+#else
+  const uint8_t *src_bytep = (const uint8_t *)src;
+  uint8_t *dst_bytep = (uint8_t *)dst;
+  dst_bytep[0] = src_bytep[0];
+  dst_bytep[1] = src_bytep[1];
+  dst_bytep[2] = src_bytep[2];
+  dst_bytep[3] = src_bytep[3];
+  dst_bytep[4] = src_bytep[4];
+  dst_bytep[5] = src_bytep[5];
+  dst_bytep[6] = src_bytep[6];
+  dst_bytep[7] = src_bytep[7];
+#endif
+}
+
+#if defined(__arm__)
+  #if ARCH_ARM_HAVE_UNALIGNED
+     static inline uint32_t get_unaligned_le(const void *p, uint32_t n)
+     {
+       uint32_t wordmask = (1U << (8 * n)) - 1;
+       return get_unaligned_le32(p) & wordmask;
+     }
+  #else
+     extern uint32_t get_unaligned_le_armv5(const void *p, uint32_t n);
+     #define get_unaligned_le get_unaligned_le_armv5
+  #endif
+#else
+  static inline uint32_t get_unaligned_le(const void *p, uint32_t n)
+  {
+    /* Mapping from i in range [0,4] to a mask to extract the bottom 8*i bits */
+    static const uint32_t wordmask[] = {
+      0u, 0xffu, 0xffffu, 0xffffffu, 0xffffffffu
+    };
+    return get_unaligned_le32(p) & wordmask[n];
+  }
+#endif
+
+#define DCHECK_EQ(a, b)	DCHECK(((a) == (b)))
+#define DCHECK_NE(a, b)	DCHECK(((a) != (b)))
+#define DCHECK_GT(a, b)	DCHECK(((a) >  (b)))
+#define DCHECK_GE(a, b)	DCHECK(((a) >= (b)))
+#define DCHECK_LT(a, b)	DCHECK(((a) <  (b)))
+#define DCHECK_LE(a, b)	DCHECK(((a) <= (b)))
+
+enum {
+	LITERAL = 0,
+	COPY_1_BYTE_OFFSET = 1,  /* 3 bit length + 3 bits of offset in opcode */
+	COPY_2_BYTE_OFFSET = 2,
+	COPY_4_BYTE_OFFSET = 3
+};
+
+#endif  /* CSNAPPY_INTERNAL_H_ */
diff --git a/drivers/staging/zram/Kconfig b/drivers/staging/zram/Kconfig
index 3bec4db..1132f4b 100644
--- a/drivers/staging/zram/Kconfig
+++ b/drivers/staging/zram/Kconfig
@@ -6,8 +6,6 @@ config ZRAM
 	tristate "Compressed RAM block device support"
 	depends on BLOCK && SYSFS
 	select XVMALLOC
-	select LZO_COMPRESS
-	select LZO_DECOMPRESS
 	default n
 	help
 	  Creates virtual block devices called /dev/zramX (X = 0, 1, ...).
@@ -28,3 +26,21 @@ config ZRAM_DEBUG
 	help
 	  This option adds additional debugging code to the compressed
 	  RAM block device driver.
+
+choice ZRAM_COMPRESS
+	prompt "compression method"
+	depends on ZRAM
+	default ZRAM_LZO
+	help
+	  Select the compression method used by zram.
+	  LZO is the default. Snappy compresses a bit worse (around ~2%) but
+	  much (~2x) faster, at least on x86-64.
+config ZRAM_LZO
+	bool "LZO compression"
+	select LZO_COMPRESS
+	select LZO_DECOMPRESS
+config ZRAM_SNAPPY
+	bool "Snappy compression"
+	depends on SNAPPY_COMPRESS
+	depends on SNAPPY_DECOMPRESS
+endchoice
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 09de99f..33cf32c 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -29,12 +29,56 @@
 #include <linux/genhd.h>
 #include <linux/highmem.h>
 #include <linux/slab.h>
-#include <linux/lzo.h>
 #include <linux/string.h>
 #include <linux/vmalloc.h>
 
 #include "zram_drv.h"
 
+#if defined(CONFIG_ZRAM_LZO)
+#include <linux/lzo.h>
+#define WMSIZE		LZO1X_MEM_COMPRESS
+#define COMPRESS(s, sl, d, dl, wm)	\
+	lzo1x_1_compress(s, sl, d, dl, wm)
+#define DECOMPRESS(s, sl, d, dl)	\
+	lzo1x_decompress_safe(s, sl, d, dl)
+#elif defined(CONFIG_ZRAM_SNAPPY)
+#include "../snappy/csnappy.h" /* if built in drivers/staging */
+#define WMSIZE_ORDER	((PAGE_SHIFT > 14) ? (15) : (PAGE_SHIFT+1))
+#define WMSIZE		(1 << WMSIZE_ORDER)
+static int
+snappy_compress_(
+	const unsigned char *src,
+	size_t src_len,
+	unsigned char *dst,
+	size_t *dst_len,
+	void *workmem)
+{
+	const unsigned char *end = csnappy_compress_fragment(
+		src, (uint32_t)src_len, dst, workmem, WMSIZE_ORDER);
+	*dst_len = end - dst;
+	return 0;
+}
+static int
+snappy_decompress_(
+	const unsigned char *src,
+	size_t src_len,
+	unsigned char *dst,
+	size_t *dst_len)
+{
+	uint32_t dst_len_ = (uint32_t)*dst_len;
+	int ret = csnappy_decompress_noheader(src, src_len, dst, &dst_len_);
+	*dst_len = (size_t)dst_len_;
+	return ret;
+}
+#define COMPRESS(s, sl, d, dl, wm)	\
+	snappy_compress_(s, sl, d, dl, wm)
+#define DECOMPRESS(s, sl, d, dl)	\
+	snappy_decompress_(s, sl, d, dl)
+#else
+#error either CONFIG_ZRAM_LZO or CONFIG_ZRAM_SNAPPY must be defined
+#endif
+
+
 /* Globals */
 static int zram_major;
 struct zram *zram_devices;
@@ -257,9 +301,9 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 	cmem = kmap_atomic(zram->table[index].page, KM_USER1) +
 		zram->table[index].offset;
 
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    xv_get_object_size(cmem) - sizeof(*zheader),
-				    uncmem, &clen);
+	ret = DECOMPRESS(cmem + sizeof(*zheader),
+			 xv_get_object_size(cmem) - sizeof(*zheader),
+			 uncmem, &clen);
 
 	if (is_partial_io(bvec)) {
 		memcpy(user_mem + bvec->bv_offset, uncmem + offset,
@@ -271,7 +315,7 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 	kunmap_atomic(user_mem, KM_USER0);
 
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret != LZO_E_OK)) {
+	if (unlikely(ret)) {
 		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
 		zram_stat64_inc(zram, &zram->stats.failed_reads);
 		return ret;
@@ -305,13 +349,13 @@ static int zram_read_before_write(struct zram *zram, char *mem, u32 index)
 		return 0;
 	}
 
-	ret = lzo1x_decompress_safe(cmem + sizeof(*zheader),
-				    xv_get_object_size(cmem) - sizeof(*zheader),
-				    mem, &clen);
+	ret = DECOMPRESS(cmem + sizeof(*zheader),
+			 xv_get_object_size(cmem) - sizeof(*zheader),
+			 mem, &clen);
 	kunmap_atomic(cmem, KM_USER0);
 
 	/* Should NEVER happen. Return bio error if it does. */
-	if (unlikely(ret != LZO_E_OK)) {
+	if (unlikely(ret)) {
 		pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
 		zram_stat64_inc(zram, &zram->stats.failed_reads);
 		return ret;
@@ -377,18 +421,12 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 		goto out;
 	}
 
-	ret = lzo1x_1_compress(uncmem, PAGE_SIZE, src, &clen,
-			       zram->compress_workmem);
+	COMPRESS(uncmem, PAGE_SIZE, src, &clen, zram->compress_workmem);
 
 	kunmap_atomic(user_mem, KM_USER0);
 	if (is_partial_io(bvec))
 			kfree(uncmem);
 
-	if (unlikely(ret != LZO_E_OK)) {
-		pr_err("Compression failed! err=%d\n", ret);
-		goto out;
-	}
-
 	/*
 	 * Page is incompressible. Store it as-is (uncompressed)
 	 * since we do not want to return too many disk write
@@ -646,7 +684,7 @@ int zram_init_device(struct zram *zram)
 
 	zram_set_disksize(zram, totalram_pages << PAGE_SHIFT);
 
-	zram->compress_workmem = kzalloc(LZO1X_MEM_COMPRESS, GFP_KERNEL);
+	zram->compress_workmem = kzalloc(WMSIZE, GFP_KERNEL);
 	if (!zram->compress_workmem) {
 		pr_err("Error allocating compressor working memory!\n");
 		ret = -ENOMEM;