block: cleanup del_gendisk a bit

Merge three hidden gendisk checks into one.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -895,6 +895,9 @@ void del_gendisk(struct gendisk *disk)
 
 	might_sleep();
 
+	if (WARN_ON_ONCE(!disk->queue))
+		return;
+
 	blk_integrity_del(disk);
 	disk_del_events(disk);
 
@@ -917,20 +920,18 @@ void del_gendisk(struct gendisk *disk)
 	disk->flags &= ~GENHD_FL_UP;
 	up_write(&disk->lookup_sem);
 
-	if (!(disk->flags & GENHD_FL_HIDDEN))
+	if (!(disk->flags & GENHD_FL_HIDDEN)) {
 		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
-	if (disk->queue) {
+
 		/*
 		 * Unregister bdi before releasing device numbers (as they can
 		 * get reused and we'd get clashes in sysfs).
 		 */
-		if (!(disk->flags & GENHD_FL_HIDDEN))
 		bdi_unregister(disk->queue->backing_dev_info);
-		blk_unregister_queue(disk);
-	} else {
-		WARN_ON(1);
 	}
 
+	blk_unregister_queue(disk);
+	
 	if (!(disk->flags & GENHD_FL_HIDDEN))
 		blk_unregister_region(disk_devt(disk), disk->minors);
 	/*