virtio-blk: use blk_mq_alloc_disk

Use the blk_mq_alloc_disk API 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/20210602065345.355274-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/virtio_blk.c

@@ -749,13 +749,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_free_vblk;
 
-	/* FIXME: How many partitions?  How long is a piece of string? */
-	vblk->disk = alloc_disk(1 << PART_BITS);
-	if (!vblk->disk) {
-		err = -ENOMEM;
-		goto out_free_vq;
-	}
-
 	/* Default queue sizing is to fill the ring. */
 	if (likely(!virtblk_queue_depth)) {
 		queue_depth = vblk->vqs[0].vq->num_free;
@@ -779,21 +772,20 @@ static int virtblk_probe(struct virtio_device *vdev)
 
 	err = blk_mq_alloc_tag_set(&vblk->tag_set);
 	if (err)
-		goto out_put_disk;
+		goto out_free_vq;
 
-	q = blk_mq_init_queue(&vblk->tag_set);
-	if (IS_ERR(q)) {
-		err = -ENOMEM;
+	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
+	if (IS_ERR(vblk->disk)) {
+		err = PTR_ERR(vblk->disk);
 		goto out_free_tags;
 	}
-	vblk->disk->queue = q;
-
-	q->queuedata = vblk;
+	q = vblk->disk->queue;
 
 	virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
 
 	vblk->disk->major = major;
 	vblk->disk->first_minor = index_to_minor(index);
+	vblk->disk->minors = 1 << PART_BITS;
 	vblk->disk->private_data = vblk;
 	vblk->disk->fops = &virtblk_fops;
 	vblk->disk->flags |= GENHD_FL_EXT_DEVT;
@@ -892,8 +884,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 
 out_free_tags:
 	blk_mq_free_tag_set(&vblk->tag_set);
-out_put_disk:
-	put_disk(vblk->disk);
 out_free_vq:
 	vdev->config->del_vqs(vdev);
 	kfree(vblk->vqs);
@@ -913,8 +903,7 @@ static void virtblk_remove(struct virtio_device *vdev)
 	flush_work(&vblk->config_work);
 
 	del_gendisk(vblk->disk);
-	blk_cleanup_queue(vblk->disk->queue);
-
+	blk_cleanup_disk(vblk->disk);
 	blk_mq_free_tag_set(&vblk->tag_set);
 
 	mutex_lock(&vblk->vdev_mutex);
@@ -925,7 +914,6 @@ static void virtblk_remove(struct virtio_device *vdev)
 	/* Virtqueues are stopped, nothing can use vblk->vdev anymore. */
 	vblk->vdev = NULL;
 
-	put_disk(vblk->disk);
 	vdev->config->del_vqs(vdev);
 	kfree(vblk->vqs);