nvme-pci: remove the barriers in nvme_irq()
The barriers were added to the nvme_irq() in commit
3a7afd8ee42a
("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
f6c4d97b0d82 ("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>