nvme: use nvme_disk_is_ns_head helper

Use nvme_disk_is_ns_head helper instead of check fops directly,
and also drop CONFIG_NVME_MULTIPATH check.

Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: guixinliu1995

drivers/nvme/host/pr.c

@@ -97,8 +97,7 @@ static int nvme_sc_to_pr_err(int nvme_sc)
 static int nvme_send_pr_command(struct block_device *bdev,
 		struct nvme_command *c, void *data, unsigned int data_len)
 {
-	if (IS_ENABLED(CONFIG_NVME_MULTIPATH) &&
-	    nvme_disk_is_ns_head(bdev->bd_disk))
+	if (nvme_disk_is_ns_head(bdev->bd_disk))
 		return nvme_send_ns_head_pr_command(bdev, c, data, data_len);
 
 	return nvme_send_ns_pr_command(bdev->bd_disk->private_data, c, data,

drivers/nvme/host/sysfs.c

@@ -236,8 +236,7 @@ static ssize_t nuse_show(struct device *dev, struct device_attribute *attr,
 	struct block_device *bdev = disk->part0;
 	int ret;
 
-	if (IS_ENABLED(CONFIG_NVME_MULTIPATH) &&
-	    bdev->bd_disk->fops == &nvme_ns_head_ops)
+	if (nvme_disk_is_ns_head(bdev->bd_disk))
 		ret = ns_head_update_nuse(head);
 	else
 		ret = ns_update_nuse(bdev->bd_disk->private_data);