nvme-pci: acquire cq_poll_lock in nvme_poll_irqdisable

We need to lock this queue for that condition because the timeout work
executes per-namespace and can poll the poll CQ.

Reported-by: Hannes Reinecke <hare@kernel.org>
Closes: https://lore.kernel.org/all/20240902130728.1999-1-hare@kernel.org/
Fixes: a0fa964 ("NVMe: add blk polling support")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/pci.c

@@ -1202,7 +1202,9 @@ static void nvme_poll_irqdisable(struct nvme_queue *nvmeq)
 	WARN_ON_ONCE(test_bit(NVMEQ_POLLED, &nvmeq->flags));
 
 	disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));
+	spin_lock(&nvmeq->cq_poll_lock);
 	nvme_poll_cq(nvmeq, NULL);
+	spin_unlock(&nvmeq->cq_poll_lock);
 	enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));
 }