5 files changed, 82 insertions, 0 deletions

diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig
index 3450be850399..6489c0fd0ea6 100644
--- a/drivers/block/zram/Kconfig
+++ b/drivers/block/zram/Kconfig
@@ -15,6 +15,16 @@ config ZRAM
 
           See zram.txt for more information.
 
+config ZRAM_LZ4_COMPRESS
+        bool "Enable LZ4 algorithm support"
+        depends on ZRAM
+        select LZ4_COMPRESS
+        select LZ4_DECOMPRESS
+        default n
+        help
+          This option enables LZ4 compression algorithm support. Compression
+          algorithm can be changed using `comp_algorithm' device attribute.
+
 config ZRAM_DEBUG
         bool "Compressed RAM block device debug support"
         depends on ZRAM
diff --git a/drivers/block/zram/Makefile b/drivers/block/zram/Makefile
index 757c6a5cadff..be0763ff57a2 100644
--- a/drivers/block/zram/Makefile
+++ b/drivers/block/zram/Makefile
@@ -1,3 +1,5 @@
 zram-y  :=      zcomp_lzo.o zcomp.o zram_drv.o
 
+zram-$(CONFIG_ZRAM_LZ4_COMPRESS) += zcomp_lz4.o
+
 obj-$(CONFIG_ZRAM)      +=      zram.o
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index aad533a8bc55..d5919031ca8b 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -15,6 +15,9 @@
 
 #include "zcomp.h"
 #include "zcomp_lzo.h"
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+#include "zcomp_lz4.h"
+#endif
 
 /*
  * single zcomp_strm backend
@@ -41,6 +44,9 @@ struct zcomp_strm_multi {
 
 static struct zcomp_backend *backends[] = {
         &zcomp_lzo,
+#ifdef CONFIG_ZRAM_LZ4_COMPRESS
+        &zcomp_lz4,
+#endif
         NULL
 };
 
diff --git a/drivers/block/zram/zcomp_lz4.c b/drivers/block/zram/zcomp_lz4.c
new file mode 100644
index 000000000000..f2afb7e988c3
--- /dev/null
+++ b/drivers/block/zram/zcomp_lz4.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/lz4.h>
+
+#include "zcomp_lz4.h"
+
+static void *zcomp_lz4_create(void)
+{
+        return kzalloc(LZ4_MEM_COMPRESS, GFP_KERNEL);
+}
+
+static void zcomp_lz4_destroy(void *private)
+{
+        kfree(private);
+}
+
+static int zcomp_lz4_compress(const unsigned char *src, unsigned char *dst,
+                size_t *dst_len, void *private)
+{
+        /* return  : Success if return 0 */
+        return lz4_compress(src, PAGE_SIZE, dst, dst_len, private);
+}
+
+static int zcomp_lz4_decompress(const unsigned char *src, size_t src_len,
+                unsigned char *dst)
+{
+        size_t dst_len = PAGE_SIZE;
+        /* return  : Success if return 0 */
+        return lz4_decompress_unknownoutputsize(src, src_len, dst, &dst_len);
+}
+
+struct zcomp_backend zcomp_lz4 = {
+        .compress = zcomp_lz4_compress,
+        .decompress = zcomp_lz4_decompress,
+        .create = zcomp_lz4_create,
+        .destroy = zcomp_lz4_destroy,
+        .name = "lz4",
+};
diff --git a/drivers/block/zram/zcomp_lz4.h b/drivers/block/zram/zcomp_lz4.h
new file mode 100644
index 000000000000..60613fb29dd8
--- /dev/null
+++ b/drivers/block/zram/zcomp_lz4.h
@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _ZCOMP_LZ4_H_
+#define _ZCOMP_LZ4_H_
+
+#include "zcomp.h"
+
+extern struct zcomp_backend zcomp_lz4;
+
+#endif /* _ZCOMP_LZ4_H_ */