1 files changed, 78 insertions, 0 deletions
diff --git a/fs/erofs/decompress.c b/fs/erofs/decompress.c
new file mode 100644
index 0000000000..2be3b844cf
--- /dev/null
+++ b/fs/erofs/decompress.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "decompress.h"
+
+#if IS_ENABLED(CONFIG_LZ4)
+#include <u-boot/lz4.h>
+static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
+{
+	int ret = 0;
+	char *dest = rq->out;
+	char *src = rq->in;
+	char *buff = NULL;
+	bool support_0padding = false;
+	unsigned int inputmargin = 0;
+
+	if (erofs_sb_has_lz4_0padding()) {
+		support_0padding = true;
+
+		while (!src[inputmargin & ~PAGE_MASK])
+			if (!(++inputmargin & ~PAGE_MASK))
+				break;
+
+		if (inputmargin >= rq->inputsize)
+			return -EIO;
+	}
+
+	if (rq->decodedskip) {
+		buff = malloc(rq->decodedlength);
+		if (!buff)
+			return -ENOMEM;
+		dest = buff;
+	}
+
+	if (rq->partial_decoding || !support_0padding)
+		ret = LZ4_decompress_safe_partial(src + inputmargin, dest,
+						  rq->inputsize - inputmargin,
+						  rq->decodedlength, rq->decodedlength);
+	else
+		ret = LZ4_decompress_safe(src + inputmargin, dest,
+					  rq->inputsize - inputmargin,
+					  rq->decodedlength);
+
+	if (ret != (int)rq->decodedlength) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (rq->decodedskip)
+		memcpy(rq->out, dest + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+
+out:
+	if (buff)
+		free(buff);
+
+	return ret;
+}
+#endif
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq)
+{
+	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
+		if (rq->inputsize != EROFS_BLKSIZ)
+			return -EFSCORRUPTED;
+
+		DBG_BUGON(rq->decodedlength > EROFS_BLKSIZ);
+		DBG_BUGON(rq->decodedlength < rq->decodedskip);
+
+		memcpy(rq->out, rq->in + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+		return 0;
+	}
+
+#if IS_ENABLED(CONFIG_LZ4)
+	if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
+		return z_erofs_decompress_lz4(rq);
+#endif
+	return -EOPNOTSUPP;
+}