nvdimm-pmem: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nvdimm-pmem 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/20210521055116.1053587-18-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvdimm/pmem.c

@@ -338,7 +338,7 @@ static void pmem_pagemap_cleanup(struct dev_pagemap *pgmap)
 	struct request_queue *q =
 		container_of(pgmap->ref, struct request_queue, q_usage_counter);
 
-	blk_cleanup_queue(q);
+	blk_cleanup_disk(queue_to_disk(q));
 }
 
 static void pmem_release_queue(void *pgmap)
@@ -361,7 +361,6 @@ static void pmem_release_disk(void *__pmem)
 	kill_dax(pmem->dax_dev);
 	put_dax(pmem->dax_dev);
 	del_gendisk(pmem->disk);
-	put_disk(pmem->disk);
 }
 
 static const struct dev_pagemap_ops fsdax_pagemap_ops = {
@@ -422,10 +421,12 @@ static int pmem_attach_disk(struct device *dev,
 		return -EBUSY;
 	}
 
-	q = blk_alloc_queue(dev_to_node(dev));
-	if (!q)
+	disk = blk_alloc_disk(nid);
+	if (!disk)
 		return -ENOMEM;
+	q = disk->queue;
 
+	pmem->disk = disk;
 	pmem->pfn_flags = PFN_DEV;
 	pmem->pgmap.ref = &q->q_usage_counter;
 	if (is_nd_pfn(dev)) {
@@ -470,11 +471,6 @@ static int pmem_attach_disk(struct device *dev,
 	if (pmem->pfn_flags & PFN_MAP)
 		blk_queue_flag_set(QUEUE_FLAG_DAX, q);
 
-	disk = alloc_disk_node(0, nid);
-	if (!disk)
-		return -ENOMEM;
-	pmem->disk = disk;
-
 	disk->fops		= &pmem_fops;
 	disk->queue		= q;
 	disk->private_data	= pmem;
@@ -490,7 +486,6 @@ static int pmem_attach_disk(struct device *dev,
 		flags = DAXDEV_F_SYNC;
 	dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags);
 	if (IS_ERR(dax_dev)) {
-		put_disk(disk);
 		return PTR_ERR(dax_dev);
 	}
 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));