nvme-pci: cap queue creation to used queues

If the user reduces the special queue count at runtime and resets the
controller, we need to reduce the number of queues and interrupts
requested accordingly rather than start with the pre-allocated queue
count.

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

@@ -2902,7 +2902,13 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	dev->nr_write_queues = write_queues;
 	dev->nr_poll_queues = poll_queues;
 
-	nr_io_queues = dev->nr_allocated_queues - 1;
+	/*
+	 * The initial number of allocated queue slots may be too large if the
+	 * user reduced the special queue parameters. Cap the value to the
+	 * number we need for this round.
+	 */
+	nr_io_queues = min(nvme_max_io_queues(dev),
+			   dev->nr_allocated_queues - 1);
 	result = nvme_set_queue_count(&dev->ctrl, &nr_io_queues);
 	if (result < 0)
 		return result;