block: move bdev_read_only() into the header

This is called for every write in the fast path, move it inline next
to get_disk_ro() which is called internally.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -1389,12 +1389,6 @@ void set_disk_ro(struct gendisk *disk, bool read_only)
 }
 EXPORT_SYMBOL(set_disk_ro);
 
-int bdev_read_only(struct block_device *bdev)
-{
-	return bdev->bd_read_only || get_disk_ro(bdev->bd_disk);
-}
-EXPORT_SYMBOL(bdev_read_only);
-
 void inc_diskseq(struct gendisk *disk)
 {
 	disk->diskseq = atomic64_inc_return(&diskseq);

include/linux/genhd.h

@@ -221,6 +221,11 @@ static inline int get_disk_ro(struct gendisk *disk)
 		test_bit(GD_READ_ONLY, &disk->state);
 }
 
+static inline int bdev_read_only(struct block_device *bdev)
+{
+	return bdev->bd_read_only || get_disk_ro(bdev->bd_disk);
+}
+
 extern void disk_block_events(struct gendisk *disk);
 extern void disk_unblock_events(struct gendisk *disk);
 extern void disk_flush_events(struct gendisk *disk, unsigned int mask);