--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -422,7 +422,7 @@ static inline int fault_in_pages_writeab
 
 static inline int fault_in_pages_readable(const char __user *uaddr, int size)
 {
-	volatile char c;
+	volatile char c __maybe_unused;
 	int ret;
 
 	if (unlikely(size == 0))