[PATCH 4/4] nvme/pci: Spin threaded interrupt completions

[Keith Busch <kbusch@kernel.org>]

For deeply queued workloads, the nvme controller may be posting
new completions while the threaded interrupt handles previous
completions. Since the interrupts are masked, we can spin for these
completions for as long as new completions are being posted.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/pci.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 571b33b69c5f..9ec0933eb120 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1042,9 +1042,15 @@ static irqreturn_t nvme_irq(int irq, void *data)
 	return ret;
 }
 
+static void nvme_irq_spin(int irq, void *data)
+{
+	while (nvme_irq(irq, data) != IRQ_NONE)
+		cond_resched();
+}
+
 static irqreturn_t nvme_irq_thread(int irq, void *data)
 {
-	nvme_irq(irq, data);
+	nvme_irq_spin(irq, data);
 	__pci_msix_desc_mask_irq(irq_get_msi_desc(irq), 0);
 	return IRQ_HANDLED;
 }
@@ -1065,7 +1071,7 @@ static irqreturn_t nvme_irq_thread_msi(int irq, void *data)
 	struct nvme_queue *nvmeq = data;
 	struct nvme_dev *dev = nvmeq->dev;
 
-	nvme_irq(irq, data);
+	nvme_irq_spin(irq, data);
 	writel(1 << nvmeq->cq_vector, dev->bar + NVME_REG_INTMC);
 	return IRQ_HANDLED;
 }
-- 
2.21.0


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