[PATCH] eventfd: add a BUILD_BUG_ON() to ensure consistency between EFD_SEMAPHORE and the uapi

[wenyang . linux]

From: Wen Yang <wenyang.linux@xxxxxxxxxxx>

introduce a BUILD_BUG_ON to check that the EFD_SEMAPHORE is equal to its
definition in the uapi file, just like EFD_CLOEXEC and EFD_NONBLOCK.

Signed-off-by: Wen Yang <wenyang.linux@xxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 fs/eventfd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/eventfd.c b/fs/eventfd.c
index 93848573c877..c1f5d71e7197 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -502,6 +502,7 @@ static int do_eventfd(unsigned int count, int flags)
 	/* Check the EFD_* constants for consistency.  */
 	BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
 	BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
+	BUILD_BUG_ON(EFD_SEMAPHORE != (1 << 0));
 
 	if (flags & ~EFD_FLAGS_SET)
 		return -EINVAL;
-- 
2.25.1