lib: add lz4 compressor module

This patchset is for supporting LZ4 compression and the crypto API using
it.

As shown below, the size of data is a little bit bigger but compressing
speed is faster under the enabled unaligned memory access.  We can use
lz4 de/compression through crypto API as well.  Also, It will be useful
for another potential user of lz4 compression.

lz4 Compression Benchmark:
Compiler: ARM gcc 4.6.4
ARMv7, 1 GHz based board
   Kernel: linux 3.4
   Uncompressed data Size: 101 MB
         Compressed Size  compression Speed
   LZO   72.1MB		  32.1MB/s, 33.0MB/s(UA)
   LZ4   75.1MB		  30.4MB/s, 35.9MB/s(UA)
   LZ4HC 59.8MB		   2.4MB/s,  2.5MB/s(UA)
- UA: Unaligned memory Access support
- Latest patch set for LZO applied

This patch:

Add support for LZ4 compression in the Linux Kernel.  LZ4 Compression APIs
for kernel are based on LZ4 implementation by Yann Collet and were changed
for kernel coding style.

LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
LZ4 source repository : http://code.google.com/p/lz4/
svn revision : r90

Two APIs are added:

lz4_compress() support basic lz4 compression whereas lz4hc_compress()
support high compression or CPU performance get lower but compression
ratio get higher.  Also, we require the pre-allocated working memory with
the defined size and destination buffer must be allocated with the size of
lz4_compressbound.

[akpm@linux-foundation.org: make lz4_compresshcctx() static]
Signed-off-by: Chanho Min <chanho.min@lge.com>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>
Cc: Bob Pearson <rpearson@systemfabricworks.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Herbert Xu <herbert@gondor.hengli.com.au>
Cc: Yann Collet <yann.collet.73@gmail.com>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/include/linux/lz4.h b/include/linux/lz4.h
index 7f6c75a093f8..d21c13f10a64 100644
--- a/include/linux/lz4.h
+++ b/include/linux/lz4.h
@@ -9,6 +9,8 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#define LZ4_MEM_COMPRESS	(4096 * sizeof(unsigned char *))
+#define LZ4HC_MEM_COMPRESS	(65538 * sizeof(unsigned char *))
 
 /*
  * lz4_compressbound()
@@ -21,6 +23,40 @@ static inline size_t lz4_compressbound(size_t isize)
 }
 
 /*
+ * lz4_compress()
+ *	src     : source address of the original data
+ *	src_len : size of the original data
+ *	dst	: output buffer address of the compressed data
+ *		This requires 'dst' of size LZ4_COMPRESSBOUND.
+ *	dst_len : is the output size, which is returned after compress done
+ *	workmem : address of the working memory.
+ *		This requires 'workmem' of size LZ4_MEM_COMPRESS.
+ *	return  : Success if return 0
+ *		  Error if return (< 0)
+ *	note :  Destination buffer and workmem must be already allocated with
+ *		the defined size.
+ */
+int lz4_compress(const unsigned char *src, size_t src_len,
+		unsigned char *dst, size_t *dst_len, void *wrkmem);
+
+ /*
+  * lz4hc_compress()
+  *	 src	 : source address of the original data
+  *	 src_len : size of the original data
+  *	 dst	 : output buffer address of the compressed data
+  *		This requires 'dst' of size LZ4_COMPRESSBOUND.
+  *	 dst_len : is the output size, which is returned after compress done
+  *	 workmem : address of the working memory.
+  *		This requires 'workmem' of size LZ4HC_MEM_COMPRESS.
+  *	 return  : Success if return 0
+  *		   Error if return (< 0)
+  *	 note :  Destination buffer and workmem must be already allocated with
+  *		 the defined size.
+  */
+int lz4hc_compress(const unsigned char *src, size_t src_len,
+		unsigned char *dst, size_t *dst_len, void *wrkmem);
+
+/*
  * lz4_decompress()
  *	src     : source address of the compressed data
  *	src_len : is the input size, whcih is returned after decompress done