nvme-pci: set doorbell config before unquiescing

During resets, if queues are unquiesced first, then the host can submit
IOs to the controller using shadow doorbell logic but the controller
won't be aware. This can lead to necessary MMIO doorbells from being
not issued, causing requests to be delayed and timed-out.

Signed-off-by: William Butler <wab@google.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

Author: tachyonwill

drivers/nvme/host/pci.c

@@ -2746,10 +2746,10 @@ static void nvme_reset_work(struct work_struct *work)
 	 * controller around but remove all namespaces.
 	 */
 	if (dev->online_queues > 1) {
+		nvme_dbbuf_set(dev);
 		nvme_unquiesce_io_queues(&dev->ctrl);
 		nvme_wait_freeze(&dev->ctrl);
 		nvme_pci_update_nr_queues(dev);
-		nvme_dbbuf_set(dev);
 		nvme_unfreeze(&dev->ctrl);
 	} else {
 		dev_warn(dev->ctrl.device, "IO queues lost\n");