nvme-multipath: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nvme-multipath driver to use the blk_alloc_disk and
blk_cleanup_disk helpers to simplify gendisk and request_queue
allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-19-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvdimm/pmem.c

@@ -472,7 +472,6 @@ static int pmem_attach_disk(struct device *dev,
 		blk_queue_flag_set(QUEUE_FLAG_DAX, q);
 
 	disk->fops		= &pmem_fops;
-	disk->queue		= q;
 	disk->private_data	= pmem;
 	nvdimm_namespace_disk_name(ndns, disk->disk_name);
 	set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset)

drivers/nvme/host/multipath.c

@@ -427,7 +427,6 @@ static void nvme_requeue_work(struct work_struct *work)
 
 int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 {
-	struct request_queue *q;
 	bool vwc = false;
 
 	mutex_init(&head->lock);
@@ -443,33 +442,24 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 	if (!(ctrl->subsys->cmic & NVME_CTRL_CMIC_MULTI_CTRL) || !multipath)
 		return 0;
 
-	q = blk_alloc_queue(ctrl->numa_node);
-	if (!q)
-		goto out;
-	blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
-	/* set to a default value for 512 until disk is validated */
-	blk_queue_logical_block_size(q, 512);
-	blk_set_stacking_limits(&q->limits);
-
-	/* we need to propagate up the VMC settings */
-	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
-		vwc = true;
-	blk_queue_write_cache(q, vwc, vwc);
-
-	head->disk = alloc_disk(0);
+	head->disk = blk_alloc_disk(ctrl->numa_node);
 	if (!head->disk)
-		goto out_cleanup_queue;
+		return -ENOMEM;
 	head->disk->fops = &nvme_ns_head_ops;
 	head->disk->private_data = head;
-	head->disk->queue = q;
 	sprintf(head->disk->disk_name, "nvme%dn%d",
 			ctrl->subsys->instance, head->instance);
-	return 0;
 
-out_cleanup_queue:
-	blk_cleanup_queue(q);
-out:
-	return -ENOMEM;
+	blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue);
+	/* set to a default value of 512 until the disk is validated */
+	blk_queue_logical_block_size(head->disk->queue, 512);
+	blk_set_stacking_limits(&head->disk->queue->limits);
+
+	/* we need to propagate up the VMC settings */
+	if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
+		vwc = true;
+	blk_queue_write_cache(head->disk->queue, vwc, vwc);
+	return 0;
 }
 
 static void nvme_mpath_set_live(struct nvme_ns *ns)
@@ -768,16 +758,7 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head)
 	/* make sure all pending bios are cleaned up */
 	kblockd_schedule_work(&head->requeue_work);
 	flush_work(&head->requeue_work);
-	blk_cleanup_queue(head->disk->queue);
-	if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
-		/*
-		 * if device_add_disk wasn't called, prevent
-		 * disk release to put a bogus reference on the
-		 * request queue
-		 */
-		head->disk->queue = NULL;
-	}
-	put_disk(head->disk);
+	blk_cleanup_disk(head->disk);
 }
 
 void nvme_mpath_init_ctrl(struct nvme_ctrl *ctrl)