bdev: move ->bd_write_holder into ->__bd_flags

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

block/bdev.c

@@ -624,7 +624,7 @@ static void bd_end_claim(struct block_device *bdev, void *holder)
 		bdev->bd_holder = NULL;
 		bdev->bd_holder_ops = NULL;
 		mutex_unlock(&bdev->bd_holder_lock);
-		if (bdev->bd_write_holder)
+		if (bdev_test_flag(bdev, BD_WRITE_HOLDER))
 			unblock = true;
 	}
 	if (!whole->bd_holders)
@@ -640,7 +640,7 @@ static void bd_end_claim(struct block_device *bdev, void *holder)
 	 */
 	if (unblock) {
 		disk_unblock_events(bdev->bd_disk);
-		bdev->bd_write_holder = false;
+		bdev_clear_flag(bdev, BD_WRITE_HOLDER);
 	}
 }
 
@@ -892,9 +892,10 @@ int bdev_open(struct block_device *bdev, blk_mode_t mode, void *holder,
 		 * writeable reference is too fragile given the way @mode is
 		 * used in blkdev_get/put().
 		 */
-		if ((mode & BLK_OPEN_WRITE) && !bdev->bd_write_holder &&
+		if ((mode & BLK_OPEN_WRITE) &&
+		    !bdev_test_flag(bdev, BD_WRITE_HOLDER) &&
 		    (disk->event_flags & DISK_EVENT_FLAG_BLOCK_ON_EXCL_WRITE)) {
-			bdev->bd_write_holder = true;
+			bdev_set_flag(bdev, BD_WRITE_HOLDER);
 			unblock_events = false;
 		}
 	}

include/linux/blk_types.h

@@ -48,7 +48,7 @@ struct block_device {
 	atomic_t		__bd_flags;	// partition number + flags
 #define BD_PARTNO		255	// lower 8 bits; assign-once
 #define BD_READ_ONLY		(1u<<8) // read-only policy
-	bool			bd_write_holder;
+#define BD_WRITE_HOLDER		(1u<<9)
 	bool			bd_has_submit_bio;
 	dev_t			bd_dev;
 	struct inode		*bd_inode;	/* will die */