diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index f856df4..3c371f7 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -710,7 +710,7 @@ cifs_get_file_info(struct file *filp)
 /* Simple function to return a 64 bit hash of string.  Rarely called */
 static __u64 simple_hashstr(const char *str)
 {
-	const __u64 hash_mult =  1125899906842597L; /* a big enough prime */
+	const __u64 hash_mult =  1125899906842597ULL; /* a big enough prime */
 	__u64 hash = 0;
 
 	while (*str)