[PATCH RFC] btrfs: fix static_assert for older gcc

[Anand Jain <anand.jain@oracle.com>]

Make is failing on gcc 8.5 with definition miss match error. It looks
like the definition of static_assert has changed

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/accessors.h | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/accessors.h b/fs/btrfs/accessors.h
index ceadfc5d6c66..c480205afac2 100644
--- a/fs/btrfs/accessors.h
+++ b/fs/btrfs/accessors.h
@@ -58,29 +58,31 @@ DECLARE_BTRFS_SETGET_BITS(16)
 DECLARE_BTRFS_SETGET_BITS(32)
 DECLARE_BTRFS_SETGET_BITS(64)
 
+#define _static_assert(x)	static_assert(x, "")
+
 #define BTRFS_SETGET_FUNCS(name, type, member, bits)			\
 static inline u##bits btrfs_##name(const struct extent_buffer *eb,	\
 				   const type *s)			\
 {									\
-	static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
+	_static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
 	return btrfs_get_##bits(eb, s, offsetof(type, member));		\
 }									\
 static inline void btrfs_set_##name(const struct extent_buffer *eb, type *s, \
 				    u##bits val)			\
 {									\
-	static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
+	_static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
 	btrfs_set_##bits(eb, s, offsetof(type, member), val);		\
 }									\
 static inline u##bits btrfs_token_##name(struct btrfs_map_token *token,	\
 					 const type *s)			\
 {									\
-	static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
+	_static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
 	return btrfs_get_token_##bits(token, s, offsetof(type, member));\
 }									\
 static inline void btrfs_set_token_##name(struct btrfs_map_token *token,\
 					  type *s, u##bits val)		\
 {									\
-	static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
+	_static_assert(sizeof(u##bits) == sizeof(((type *)0))->member);	\
 	btrfs_set_token_##bits(token, s, offsetof(type, member), val);	\
 }
 
@@ -111,7 +113,7 @@ static inline void btrfs_set_##name(type *s, u##bits val)		\
 static inline u64 btrfs_device_total_bytes(const struct extent_buffer *eb,
 					   struct btrfs_dev_item *s)
 {
-	static_assert(sizeof(u64) ==
+	_static_assert(sizeof(u64) ==
 		      sizeof(((struct btrfs_dev_item *)0))->total_bytes);
 	return btrfs_get_64(eb, s, offsetof(struct btrfs_dev_item,
 					    total_bytes));
@@ -120,7 +122,7 @@ static inline void btrfs_set_device_total_bytes(const struct extent_buffer *eb,
 						struct btrfs_dev_item *s,
 						u64 val)
 {
-	static_assert(sizeof(u64) ==
+	_static_assert(sizeof(u64) ==
 		      sizeof(((struct btrfs_dev_item *)0))->total_bytes);
 	WARN_ON(!IS_ALIGNED(val, eb->fs_info->sectorsize));
 	btrfs_set_64(eb, s, offsetof(struct btrfs_dev_item, total_bytes), val);
-- 
2.38.1