diff --git a/include/linux/lz4.h b/include/linux/lz4.h
index d21c13f10a6471590f0a783a53eabfbba9571051..4356686b0a3914a2d47271ca87ff74943782be42 100644
--- a/include/linux/lz4.h
+++ b/include/linux/lz4.h
@@ -67,8 +67,8 @@ int lz4hc_compress(const unsigned char *src, size_t src_len,
  *	note :  Destination buffer must be already allocated.
  *		slightly faster than lz4_decompress_unknownoutputsize()
  */
-int lz4_decompress(const char *src, size_t *src_len, char *dest,
-		size_t actual_dest_len);
+int lz4_decompress(const unsigned char *src, size_t *src_len,
+		unsigned char *dest, size_t actual_dest_len);
 
 /*
  * lz4_decompress_unknownoutputsize()
@@ -82,6 +82,6 @@ int lz4_decompress(const char *src, size_t *src_len, char *dest,
  *		  Error if return (< 0)
  *	note :  Destination buffer must be already allocated.
  */
-int lz4_decompress_unknownoutputsize(const char *src, size_t src_len,
-		char *dest, size_t *dest_len);
+int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
+		unsigned char *dest, size_t *dest_len);
 #endif
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index 411be80ddb46942242fb11013844219f8a5bf39c..df6839e3ce0886a481e8565f8b19d5c71c9b299a 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -283,8 +283,8 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 	return (int) (-(((char *) ip) - source));
 }
 
-int lz4_decompress(const char *src, size_t *src_len, char *dest,
-		size_t actual_dest_len)
+int lz4_decompress(const unsigned char *src, size_t *src_len,
+		unsigned char *dest, size_t actual_dest_len)
 {
 	int ret = -1;
 	int input_len = 0;
@@ -302,8 +302,8 @@ int lz4_decompress(const char *src, size_t *src_len, char *dest,
 EXPORT_SYMBOL(lz4_decompress);
 #endif
 
-int lz4_decompress_unknownoutputsize(const char *src, size_t src_len,
-		char *dest, size_t *dest_len)
+int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
+		unsigned char *dest, size_t *dest_len)
 {
 	int ret = -1;
 	int out_len = 0;