block: make function 'kill_bdev' static

kill_bdev does not have any external user, so make it static.
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/block_dev.c

@@ -75,7 +75,7 @@ static void bdev_write_inode(struct block_device *bdev)
 }
 
 /* Kill _all_ buffers and pagecache , dirty or not.. */
-void kill_bdev(struct block_device *bdev)
+static void kill_bdev(struct block_device *bdev)
 {
 	struct address_space *mapping = bdev->bd_inode->i_mapping;
 
@@ -85,7 +85,6 @@ void kill_bdev(struct block_device *bdev)
 	invalidate_bh_lrus();
 	truncate_inode_pages(mapping, 0);
 }
-EXPORT_SYMBOL(kill_bdev);
 
 /* Invalidate clean unused buffers and pagecache. */
 void invalidate_bdev(struct block_device *bdev)

include/linux/fs.h

@@ -2592,7 +2592,6 @@ extern void bdput(struct block_device *);
 extern void invalidate_bdev(struct block_device *);
 extern void iterate_bdevs(void (*)(struct block_device *, void *), void *);
 extern int sync_blockdev(struct block_device *bdev);
-extern void kill_bdev(struct block_device *);
 extern struct super_block *freeze_bdev(struct block_device *);
 extern void emergency_thaw_all(void);
 extern void emergency_thaw_bdev(struct super_block *sb);
@@ -2608,7 +2607,6 @@ static inline bool sb_is_blkdev_sb(struct super_block *sb)
 #else
 static inline void bd_forget(struct inode *inode) {}
 static inline int sync_blockdev(struct block_device *bdev) { return 0; }
-static inline void kill_bdev(struct block_device *bdev) {}
 static inline void invalidate_bdev(struct block_device *bdev) {}
 
 static inline struct super_block *freeze_bdev(struct block_device *sb)