Commit e9c78c23 authored by Chaitanya Kulkarni's avatar Chaitanya Kulkarni Committed by Christoph Hellwig
Browse files

nvme-pci: remove the barriers in nvme_irq() 



The barriers were added to the nvme_irq() in commit 3a7afd8e
("nvme-pci: remove the CQ lock for interrupt driven queues") to prevent
compiler from doing memory optimization for the variabes that were
protected previously by spinlock in nvme_irq() at completion queue
processing and with queue head check condition.

The variable nvmeq->last_cq_head from those checks was removed in the
commit f6c4d97b ("nvme/pci: Remove last_cq_head") that was not
allwing poll queues from mistakenly triggering the spurious interrupt
detection.

Remove the barriers which were protecting the updates to the variables.

Reported-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 80755855

drivers/nvme/host/pci.c

+0 −6
Original line number Diff line number Diff line
@@ -1062,14 +1062,8 @@ static irqreturn_t nvme_irq(int irq, void *data) 
	struct nvme_queue *nvmeq = data;

	irqreturn_t ret = IRQ_NONE;



	/*

	 * The rmb/wmb pair ensures we see all updates from a previous run of

	 * the irq handler, even if that was on another CPU.

	 */

	rmb();

	if (nvme_process_cq(nvmeq))

		ret = IRQ_HANDLED;

	wmb();



	return ret;

}