diff --git a/include/uapi/linux/cn_proc.h b/include/uapi/linux/cn_proc.h
index f2afb7cc4926..18e3745b86cd 100644
--- a/include/uapi/linux/cn_proc.h
+++ b/include/uapi/linux/cn_proc.h
@@ -69,8 +69,7 @@ struct proc_input {
 
 static inline enum proc_cn_event valid_event(enum proc_cn_event ev_type)
 {
-	ev_type &= PROC_EVENT_ALL;
-	return ev_type;
+	return (enum proc_cn_event)(ev_type & PROC_EVENT_ALL);
 }
 
 /*