1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
new file mode 100644
index 000000000000..0f7f252c12f4
--- /dev/null
+++ b/drivers/block/zram/backend_deflate.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/zlib.h>
+
+#include "backend_deflate.h"
+
+/* Use the same value as crypto API */
+#define DEFLATE_DEF_WINBITS		11
+#define DEFLATE_DEF_MEMLEVEL		MAX_MEM_LEVEL
+
+struct deflate_ctx {
+	struct z_stream_s cctx;
+	struct z_stream_s dctx;
+};
+
+static void deflate_release_params(struct zcomp_params *params)
+{
+}
+
+static int deflate_setup_params(struct zcomp_params *params)
+{
+	if (params->level == ZCOMP_PARAM_NO_LEVEL)
+		params->level = Z_DEFAULT_COMPRESSION;
+
+	return 0;
+}
+
+static void deflate_destroy(struct zcomp_ctx *ctx)
+{
+	struct deflate_ctx *zctx = ctx->context;
+
+	if (!zctx)
+		return;
+
+	if (zctx->cctx.workspace) {
+		zlib_deflateEnd(&zctx->cctx);
+		vfree(zctx->cctx.workspace);
+	}
+	if (zctx->dctx.workspace) {
+		zlib_inflateEnd(&zctx->dctx);
+		vfree(zctx->dctx.workspace);
+	}
+	kfree(zctx);
+}
+
+static int deflate_create(struct zcomp_params *params, struct zcomp_ctx *ctx)
+{
+	struct deflate_ctx *zctx;
+	size_t sz;
+	int ret;
+
+	zctx = kzalloc(sizeof(*zctx), GFP_KERNEL);
+	if (!zctx)
+		return -ENOMEM;
+
+	ctx->context = zctx;
+	sz = zlib_deflate_workspacesize(-DEFLATE_DEF_WINBITS, MAX_MEM_LEVEL);
+	zctx->cctx.workspace = vzalloc(sz);
+	if (!zctx->cctx.workspace)
+		goto error;
+
+	ret = zlib_deflateInit2(&zctx->cctx, params->level, Z_DEFLATED,
+				-DEFLATE_DEF_WINBITS, DEFLATE_DEF_MEMLEVEL,
+				Z_DEFAULT_STRATEGY);
+	if (ret != Z_OK)
+		goto error;
+
+	sz = zlib_inflate_workspacesize();
+	zctx->dctx.workspace = vzalloc(sz);
+	if (!zctx->dctx.workspace)
+		goto error;
+
+	ret = zlib_inflateInit2(&zctx->dctx, -DEFLATE_DEF_WINBITS);
+	if (ret != Z_OK)
+		goto error;
+
+	return 0;
+
+error:
+	deflate_destroy(ctx);
+	return -EINVAL;
+}
+
+static int deflate_compress(struct zcomp_params *params, struct zcomp_ctx *ctx,
+			    struct zcomp_req *req)
+{
+	struct deflate_ctx *zctx = ctx->context;
+	struct z_stream_s *deflate;
+	int ret;
+
+	deflate = &zctx->cctx;
+	ret = zlib_deflateReset(deflate);
+	if (ret != Z_OK)
+		return -EINVAL;
+
+	deflate->next_in = (u8 *)req->src;
+	deflate->avail_in = req->src_len;
+	deflate->next_out = (u8 *)req->dst;
+	deflate->avail_out = req->dst_len;
+
+	ret = zlib_deflate(deflate, Z_FINISH);
+	if (ret != Z_STREAM_END)
+		return -EINVAL;
+
+	req->dst_len = deflate->total_out;
+	return 0;
+}
+
+static int deflate_decompress(struct zcomp_params *params,
+			      struct zcomp_ctx *ctx,
+			      struct zcomp_req *req)
+{
+	struct deflate_ctx *zctx = ctx->context;
+	struct z_stream_s *inflate;
+	int ret;
+
+	inflate = &zctx->dctx;
+
+	ret = zlib_inflateReset(inflate);
+	if (ret != Z_OK)
+		return -EINVAL;
+
+	inflate->next_in = (u8 *)req->src;
+	inflate->avail_in = req->src_len;
+	inflate->next_out = (u8 *)req->dst;
+	inflate->avail_out = req->dst_len;
+
+	ret = zlib_inflate(inflate, Z_SYNC_FLUSH);
+	if (ret != Z_STREAM_END)
+		return -EINVAL;
+
+	return 0;
+}
+
+const struct zcomp_ops backend_deflate = {
+	.compress	= deflate_compress,
+	.decompress	= deflate_decompress,
+	.create_ctx	= deflate_create,
+	.destroy_ctx	= deflate_destroy,
+	.setup_params	= deflate_setup_params,
+	.release_params	= deflate_release_params,
+	.name		= "deflate",
+};