nvme-pci: disable controller on admin queue IRQ setup failure

nvme_pci_configure_admin_queue() enables the controller and then requests
the admin queue interrupt. If queue_request_irq() fails it returns without
disabling the controller, and no caller compensates: nvme_pci_enable() only
frees the IRQ vectors and calls pci_disable_device(), after which
nvme_dev_disable() treats the controller as dead and skips nvme_disable_ctrl().
The controller is left enabled (CC.EN set) on this error path.

Disable it in the failure path, while the PCI device is still enabled so the
CC.EN clear handshake completes.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: b60503ba43 ("NVMe: New driver")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/pci.c

@@ -2414,6 +2414,7 @@ static int nvme_pci_configure_admin_queue(struct nvme_dev *dev)
 	result = queue_request_irq(nvmeq);
 	if (result) {
 		dev->online_queues--;
+		nvme_disable_ctrl(&dev->ctrl, false);
 		return result;
 	}