diff --git a/fs/char_dev.c b/fs/char_dev.c
index e5b9df9..143f020 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -59,7 +59,7 @@
 } *chrdevs[CHRDEV_MAJOR_HASH_SIZE];
 
 /* index in the above */
-static inline int major_to_index(int major)
+static inline int major_to_index(unsigned major)
 {
 	return major % CHRDEV_MAJOR_HASH_SIZE;
 }