diff --git a/drivers/md/bcache/bcache_ondisk.h b/drivers/md/bcache/bcache_ondisk.h
index f96034e0ba4f20..6620a7f8fffc4d 100644
--- a/drivers/md/bcache/bcache_ondisk.h
+++ b/drivers/md/bcache/bcache_ondisk.h
@@ -360,8 +360,8 @@ struct jset {
 	__u64			prio_bucket[MAX_CACHES_PER_SET];
 
 	union {
-		struct bkey	start[0];
-		__u64		d[0];
+		DECLARE_FLEX_ARRAY(struct bkey, start);
+		DECLARE_FLEX_ARRAY(__u64, d);
 	};
 };
 
@@ -425,8 +425,8 @@ struct bset {
 	__u32			keys;
 
 	union {
-		struct bkey	start[0];
-		__u64		d[0];
+		DECLARE_FLEX_ARRAY(struct bkey, start);
+		DECLARE_FLEX_ARRAY(__u64, d);
 	};
 };
 
diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index 9f4d4bcbf251d2..601700fedc91c5 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -131,7 +131,7 @@ struct fid {
  			u32 parent_block;
  			u32 parent_generation;
  		} udf;
-		__u32 raw[0];
+		DECLARE_FLEX_ARRAY(__u32, raw);
 	};
 };
 
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 7fcaf3180a5b62..1314d9c5f05b0e 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);
 	};
 };