[PATCH 3/4] nvme/pci: Mask MSIx interrupts for threaded handling

[Keith Busch <kbusch@kernel.org>]

The nvme irq thread, when enabled, may run for a while as new completions
are submitted. These completions may also send MSI messages, which could
be detected as spurious and disables the nvme irq.

Use the fast MSIx mask to disable the controller from sending MSIx
interrupts while the nvme bottom half thread is running.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/pci.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index c5b837cba730..571b33b69c5f 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -13,11 +13,13 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/irq.h>
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/once.h>
 #include <linux/pci.h>
+#include <linux/msi.h>
 #include <linux/suspend.h>
 #include <linux/t10-pi.h>
 #include <linux/types.h>
@@ -1040,11 +1042,21 @@ static irqreturn_t nvme_irq(int irq, void *data)
 	return ret;
 }
 
+static irqreturn_t nvme_irq_thread(int irq, void *data)
+{
+	nvme_irq(irq, data);
+	__pci_msix_desc_mask_irq(irq_get_msi_desc(irq), 0);
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t nvme_irq_check(int irq, void *data)
 {
 	struct nvme_queue *nvmeq = data;
-	if (nvme_cqe_pending(nvmeq))
+
+	if (nvme_cqe_pending(nvmeq)) {
+		__pci_msix_desc_mask_irq(irq_get_msi_desc(irq), 1);
 		return IRQ_WAKE_THREAD;
+	}
 	return IRQ_NONE;
 }
 
@@ -1530,7 +1542,8 @@ static int queue_request_irq(struct nvme_queue *nvmeq)
 				nvme_irq_check_msi, nvme_irq_thread_msi,
 				nvmeq, "nvme%dq%d", nr, nvmeq->qid);
 		return pci_request_irq(pdev, nvmeq->cq_vector, nvme_irq_check,
-				nvme_irq, nvmeq, "nvme%dq%d", nr, nvmeq->qid);
+				nvme_irq_thread, nvmeq, "nvme%dq%d", nr,
+				nvmeq->qid);
 	} else {
 		return pci_request_irq(pdev, nvmeq->cq_vector, nvme_irq,
 				NULL, nvmeq, "nvme%dq%d", nr, nvmeq->qid);
-- 
2.21.0


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