1 files changed, 72 insertions, 0 deletions
diff --git a/drivers/block/zram/backend_lz4hc.c b/drivers/block/zram/backend_lz4hc.c
new file mode 100644
index 000000000000..536f7a0073c4
--- /dev/null
+++ b/drivers/block/zram/backend_lz4hc.c
@@ -0,0 +1,72 @@
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "backend_lz4hc.h"
+
+struct lz4hc_ctx {
+	void *mem;
+	s32 level;
+};
+
+static void lz4hc_destroy(void *ctx)
+{
+	struct lz4hc_ctx *zctx = ctx;
+
+	vfree(zctx->mem);
+	kfree(zctx);
+}
+
+static void *lz4hc_create(void)
+{
+	struct lz4hc_ctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	/* @FIXME: using a hardcoded LZ4HC_DEFAULT_CLEVEL for now */
+	ctx->level = LZ4HC_DEFAULT_CLEVEL;
+	ctx->mem = vmalloc(LZ4HC_MEM_COMPRESS);
+	if (!ctx->mem)
+		goto error;
+
+	return ctx;
+error:
+	lz4hc_destroy(ctx);
+	return NULL;
+}
+
+static int lz4hc_compress(void *ctx, const unsigned char *src, size_t src_len,
+			  unsigned char *dst, size_t *dst_len)
+{
+	struct lz4hc_ctx *zctx = ctx;
+	int ret;
+
+	ret = LZ4_compress_HC(src, dst, src_len, *dst_len,
+			      zctx->level, zctx->mem);
+	if (!ret)
+		return -EINVAL;
+	*dst_len = ret;
+	return 0;
+}
+
+static int lz4hc_decompress(void *ctx, const unsigned char *src,
+			    size_t src_len, unsigned char *dst, size_t dst_len)
+{
+	int ret;
+
+	ret = LZ4_decompress_safe(src, dst, src_len, dst_len);
+	if (ret < 0)
+		return -EINVAL;
+	return 0;
+}
+
+const struct zcomp_ops backend_lz4hc = {
+	.compress	= lz4hc_compress,
+	.decompress	= lz4hc_decompress,
+	.create_ctx	= lz4hc_create,
+	.destroy_ctx	= lz4hc_destroy,
+	.name		= "lz4hc",
+};