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nvme-pci: remove the barriers in nvme_irq()

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The barriers were added to the nvme_irq() in commit 3a7afd8ee4
("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 f6c4d97b0d ("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: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Chaitanya Kulkarni 2021-02-23 12:47:40 -08:00 committed by Christoph Hellwig
parent 80755855f8
commit e9c78c2335
1 changed files with 0 additions and 6 deletions
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6
drivers/nvme/host/pci.c
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@ -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;
}