diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 7fcaf3180a5b..1314d9c5f05b 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -135,7 +135,7 @@ struct dev_pagemap {
 	int nr_range;
 	union {
 		struct range range;
-		struct range ranges[0];
+		DECLARE_FLEX_ARRAY(struct range, ranges);
 	};
 };