[PATCH 1/3] nvme-pci: ensure we're polling a polled queue

[Keith Busch]

From: Keith Busch <kbusch at kernel.org>

A user can change the polled queue count at run time. There's a brief
window during a reset where a hipri task may try to poll that queue
before the block layer has updated the queue maps, which would race with
the now irq driven queue, which can cause double completions.

Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 drivers/nvme/host/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 80df992d1ae82..5a3e27305176f 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1496,7 +1496,8 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
 	struct nvme_queue *nvmeq = hctx->driver_data;
 	bool found;
 
-	if (!nvme_cqe_pending(nvmeq))
+	if (!test_bit(NVMEQ_POLLED, &nvmeq->flags) ||
+	    !nvme_cqe_pending(nvmeq))
 		return 0;
 
 	spin_lock(&nvmeq->cq_poll_lock);
-- 
2.47.3