nvme-pci: do not try to add queue maps at runtime

The block layer allocates the set's maps once. We can't add special
purpose queues at runtime if they weren't allocated at initialization
time.

Tested-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: keithbusch

drivers/nvme/host/pci.c

@@ -2902,6 +2902,18 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	dev->nr_write_queues = write_queues;
 	dev->nr_poll_queues = poll_queues;
 
+	if (dev->ctrl.tagset) {
+		/*
+		 * The set's maps are allocated only once at initialization
+		 * time. We can't add special queues later if their mq_map
+		 * wasn't preallocated.
+		 */
+		if (dev->ctrl.tagset->nr_maps < 3)
+			dev->nr_poll_queues = 0;
+		if (dev->ctrl.tagset->nr_maps < 2)
+			dev->nr_write_queues = 0;
+	}
+
 	/*
 	 * The initial number of allocated queue slots may be too large if the
 	 * user reduced the special queue parameters. Cap the value to the