rbd: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-23-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/rbd.c

@@ -4750,9 +4750,8 @@ static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 static void rbd_free_disk(struct rbd_device *rbd_dev)
 {
-	blk_cleanup_queue(rbd_dev->disk->queue);
+	blk_cleanup_disk(rbd_dev->disk);
 	blk_mq_free_tag_set(&rbd_dev->tag_set);
-	put_disk(rbd_dev->disk);
 	rbd_dev->disk = NULL;
 }
 
@@ -4922,22 +4921,6 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	    rbd_dev->layout.object_size * rbd_dev->layout.stripe_count;
 	int err;
 
-	/* create gendisk info */
-	disk = alloc_disk(single_major ?
-			  (1 << RBD_SINGLE_MAJOR_PART_SHIFT) :
-			  RBD_MINORS_PER_MAJOR);
-	if (!disk)
-		return -ENOMEM;
-
-	snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
-		 rbd_dev->dev_id);
-	disk->major = rbd_dev->major;
-	disk->first_minor = rbd_dev->minor;
-	if (single_major)
-		disk->flags |= GENHD_FL_EXT_DEVT;
-	disk->fops = &rbd_bd_ops;
-	disk->private_data = rbd_dev;
-
 	memset(&rbd_dev->tag_set, 0, sizeof(rbd_dev->tag_set));
 	rbd_dev->tag_set.ops = &rbd_mq_ops;
 	rbd_dev->tag_set.queue_depth = rbd_dev->opts->queue_depth;
@@ -4948,13 +4931,26 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 
 	err = blk_mq_alloc_tag_set(&rbd_dev->tag_set);
 	if (err)
-		goto out_disk;
+		return err;
 
-	q = blk_mq_init_queue(&rbd_dev->tag_set);
-	if (IS_ERR(q)) {
-		err = PTR_ERR(q);
+	disk = blk_mq_alloc_disk(&rbd_dev->tag_set, rbd_dev);
+	if (IS_ERR(disk)) {
+		err = PTR_ERR(disk);
 		goto out_tag_set;
 	}
+	q = disk->queue;
+
+	snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
+		 rbd_dev->dev_id);
+	disk->major = rbd_dev->major;
+	disk->first_minor = rbd_dev->minor;
+	if (single_major) {
+		disk->minors = (1 << RBD_SINGLE_MAJOR_PART_SHIFT);
+		disk->flags |= GENHD_FL_EXT_DEVT;
+	} else {
+		disk->minors = RBD_MINORS_PER_MAJOR;
+	}
+	disk->fops = &rbd_bd_ops;
 
 	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
 	/* QUEUE_FLAG_ADD_RANDOM is off by default for blk-mq */
@@ -4976,21 +4972,11 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
 		blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, q);
 
-	/*
-	 * disk_release() expects a queue ref from add_disk() and will
-	 * put it.  Hold an extra ref until add_disk() is called.
-	 */
-	WARN_ON(!blk_get_queue(q));
-	disk->queue = q;
-	q->queuedata = rbd_dev;
-
 	rbd_dev->disk = disk;
 
 	return 0;
 out_tag_set:
 	blk_mq_free_tag_set(&rbd_dev->tag_set);
-out_disk:
-	put_disk(disk);
 	return err;
 }
 
@@ -7088,8 +7074,6 @@ static ssize_t do_rbd_add(struct bus_type *bus,
 		goto err_out_image_lock;
 
 	device_add_disk(&rbd_dev->dev, rbd_dev->disk, NULL);
-	/* see rbd_init_disk() */
-	blk_put_queue(rbd_dev->disk->queue);
 
 	spin_lock(&rbd_dev_list_lock);
 	list_add_tail(&rbd_dev->node, &rbd_dev_list);