diff --git a/include/kfifo.h b/include/kfifo.h
index 6f8be10..3eb03cb 100644
--- a/include/kfifo.h
+++ b/include/kfifo.h
@@ -43,7 +43,7 @@
  * bytes copied.
  */
 unsigned int kfifo_put(struct kfifo *fifo,
-				unsigned char *buffer, unsigned int len);
+				const unsigned char *buffer, unsigned int len);
 
 /**
  * kfifo_get - gets some data from the FIFO
diff --git a/lib/kfifo.c b/lib/kfifo.c
index bf5cee1..27d44e9 100644
--- a/lib/kfifo.c
+++ b/lib/kfifo.c
@@ -96,7 +96,7 @@
  *
  */
 unsigned int kfifo_put(struct kfifo *fifo,
-			 unsigned char *buffer, unsigned int len)
+			 const unsigned char *buffer, unsigned int len)
 {
 	unsigned int l;