zram: convert to blk_alloc_disk/blk_cleanup_disk

Convert the zram 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/20210521055116.1053587-11-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/zram/zram_drv.c

@@ -1890,7 +1890,6 @@ static const struct attribute_group *zram_disk_attr_groups[] = {
 static int zram_add(void)
 {
 	struct zram *zram;
-	struct request_queue *queue;
 	int ret, device_id;
 
 	zram = kzalloc(sizeof(struct zram), GFP_KERNEL);
@@ -1906,27 +1905,20 @@ static int zram_add(void)
 #ifdef CONFIG_ZRAM_WRITEBACK
 	spin_lock_init(&zram->wb_limit_lock);
 #endif
-	queue = blk_alloc_queue(NUMA_NO_NODE);
-	if (!queue) {
-		pr_err("Error allocating disk queue for device %d\n",
-			device_id);
-		ret = -ENOMEM;
-		goto out_free_idr;
-	}
 
 	/* gendisk structure */
-	zram->disk = alloc_disk(1);
+	zram->disk = blk_alloc_disk(NUMA_NO_NODE);
 	if (!zram->disk) {
 		pr_err("Error allocating disk structure for device %d\n",
 			device_id);
 		ret = -ENOMEM;
-		goto out_free_queue;
+		goto out_free_idr;
 	}
 
 	zram->disk->major = zram_major;
 	zram->disk->first_minor = device_id;
+	zram->disk->minors = 1;
 	zram->disk->fops = &zram_devops;
-	zram->disk->queue = queue;
 	zram->disk->private_data = zram;
 	snprintf(zram->disk->disk_name, 16, "zram%d", device_id);
 
@@ -1969,8 +1961,6 @@ static int zram_add(void)
 	pr_info("Added device: %s\n", zram->disk->disk_name);
 	return device_id;
 
-out_free_queue:
-	blk_cleanup_queue(queue);
 out_free_idr:
 	idr_remove(&zram_index_idr, device_id);
 out_free_dev:
@@ -2000,8 +1990,7 @@ static int zram_remove(struct zram *zram)
 	pr_info("Removed device: %s\n", zram->disk->disk_name);
 
 	del_gendisk(zram->disk);
-	blk_cleanup_queue(zram->disk->queue);
-	put_disk(zram->disk);
+	blk_cleanup_disk(zram->disk);
 	kfree(zram);
 	return 0;
 }