From: Keith Busch <kbusch@kernel.org>

Date: Wed, 4 Mar 2020 09:17:01 -0800

Subject: [PATCH] nvme-pci: Simplify nvme_poll_irqdisable

Git-commit: fa059b856a593a7bddd4d3779ae8ab1380e05d91

Patch-mainline: v5.7-rc1

References: git-fixes

The timeout handler can use the existing nvme_poll() if it needs to

check a polled queue, allowing nvme_poll_irqdisable() to handle only

irq driven queues for the remaining callers.

Signed-off-by: Keith Busch <kbusch@kernel.org>

Acked-by: Hannes Reinecke <hare@suse.com>

---

 drivers/nvme/host/pci.c | 30 +++++++++++-------------------

 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c

index 02f22c63adcf..f45e26e6af7e 100644

--- a/drivers/nvme/host/pci.c

+++ b/drivers/nvme/host/pci.c

@@ -1020,30 +1020,18 @@ static irqreturn_t nvme_irq_check(int irq, void *data)

 }

 /*

- * Poll for completions any queue, including those not dedicated to polling.

+ * Poll for completions for any interrupt driven queue

  * Can be called from any context.

  */

-static int nvme_poll_irqdisable(struct nvme_queue *nvmeq)

+static void nvme_poll_irqdisable(struct nvme_queue *nvmeq)

 {

 	struct pci_dev *pdev = to_pci_dev(nvmeq->dev->dev);

-	int found;

-	/*

-	 * For a poll queue we need to protect against the polling thread

-	 * using the CQ lock.  For normal interrupt driven threads we have

-	 * to disable the interrupt to avoid racing with it.

-	 */

-	if (test_bit(NVMEQ_POLLED, &nvmeq->flags)) {

-		spin_lock(&nvmeq->cq_poll_lock);

-		found = nvme_process_cq(nvmeq);

-		spin_unlock(&nvmeq->cq_poll_lock);

-	} else {

-		disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));

-		found = nvme_process_cq(nvmeq);

-		enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));

-	}

+	WARN_ON_ONCE(test_bit(NVMEQ_POLLED, &nvmeq->flags));

-	return found;

+	disable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));

+	nvme_process_cq(nvmeq);

+	enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector));

 }

 static int nvme_poll(struct blk_mq_hw_ctx *hctx)

@@ -1232,7 +1220,11 @@ static enum blk_eh_timer_return nvme_timeout(struct request *req, bool reserved)

 	/*

 	 * Did we miss an interrupt?

 	 */

-	nvme_poll_irqdisable(nvmeq);

+	if (test_bit(NVMEQ_POLLED, &nvmeq->flags))

+		nvme_poll(req->mq_hctx);

+	else

+		nvme_poll_irqdisable(nvmeq);

+

 	if (blk_mq_request_completed(req)) {

 		dev_warn(dev->ctrl.device,

 			 "I/O %d QID %d timeout, completion polled\n",

-- 

2.29.2