1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/block/zram/backend_lz4.c b/drivers/block/zram/backend_lz4.c
new file mode 100644
index 000000000000..847f3334eb38
--- /dev/null
+++ b/drivers/block/zram/backend_lz4.c
@@ -0,0 +1,127 @@
+#include <linux/kernel.h>
+#include <linux/lz4.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+
+#include "backend_lz4.h"
+
+struct lz4_ctx {
+	void *mem;
+
+	LZ4_streamDecode_t *dstrm;
+	LZ4_stream_t *cstrm;
+};
+
+static void lz4_release_params(struct zcomp_params *params)
+{
+}
+
+static int lz4_setup_params(struct zcomp_params *params)
+{
+	if (params->level == ZCOMP_PARAM_NO_LEVEL)
+		params->level = LZ4_ACCELERATION_DEFAULT;
+
+	return 0;
+}
+
+static void lz4_destroy(struct zcomp_ctx *ctx)
+{
+	struct lz4_ctx *zctx = ctx->context;
+
+	if (!zctx)
+		return;
+
+	vfree(zctx->mem);
+	kfree(zctx->dstrm);
+	kfree(zctx->cstrm);
+	kfree(zctx);
+}
+
+static int lz4_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
+{
+	struct lz4_ctx *zctx;
+
+	zctx = kzalloc(sizeof(*zctx), GFP_KERNEL);
+	if (!zctx)
+		return -ENOMEM;
+
+	ctx->context = zctx;
+	if (params->dict_sz == 0) {
+		zctx->mem = vmalloc(LZ4_MEM_COMPRESS);
+		if (!zctx->mem)
+			goto error;
+	} else {
+		zctx->dstrm = kzalloc(sizeof(*zctx->dstrm), GFP_KERNEL);
+		if (!zctx->dstrm)
+			goto error;
+
+		zctx->cstrm = kzalloc(sizeof(*zctx->cstrm), GFP_KERNEL);
+		if (!zctx->cstrm)
+			goto error;
+	}
+
+	return 0;
+
+error:
+	lz4_destroy(ctx);
+	return -ENOMEM;
+}
+
+static int lz4_compress(struct zcomp_params *params, struct zcomp_ctx *ctx,
+			struct zcomp_req *req)
+{
+	struct lz4_ctx *zctx = ctx->context;
+	int ret;
+
+	if (!zctx->cstrm) {
+		ret = LZ4_compress_fast(req->src, req->dst, req->src_len,
+					req->dst_len, params->level,
+					zctx->mem);
+	} else {
+		/* Cstrm needs to be reset */
+		ret = LZ4_loadDict(zctx->cstrm, params->dict, params->dict_sz);
+		if (ret != params->dict_sz)
+			return -EINVAL;
+		ret = LZ4_compress_fast_continue(zctx->cstrm, req->src,
+						 req->dst, req->src_len,
+						 req->dst_len, params->level);
+	}
+	if (!ret)
+		return -EINVAL;
+	req->dst_len = ret;
+	return 0;
+}
+
+static int lz4_decompress(struct zcomp_params *params, struct zcomp_ctx *ctx,
+			  struct zcomp_req *req)
+{
+	struct lz4_ctx *zctx = ctx->context;
+	int ret;
+
+	if (!zctx->dstrm) {
+		ret = LZ4_decompress_safe(req->src, req->dst, req->src_len,
+					  req->dst_len);
+	} else {
+		/* Dstrm needs to be reset */
+		ret = LZ4_setStreamDecode(zctx->dstrm, params->dict,
+					  params->dict_sz);
+		if (!ret)
+			return -EINVAL;
+		ret = LZ4_decompress_safe_continue(zctx->dstrm, req->src,
+						   req->dst, req->src_len,
+						   req->dst_len);
+	}
+	if (ret < 0)
+		return -EINVAL;
+	return 0;
+}
+
+const struct zcomp_ops backend_lz4 = {
+	.compress	= lz4_compress,
+	.decompress	= lz4_decompress,
+	.create_ctx	= lz4_create,
+	.destroy_ctx	= lz4_destroy,
+	.setup_params	= lz4_setup_params,
+	.release_params	= lz4_release_params,
+	.name		= "lz4",
+};