On 2/18/21 11:37 PM, Chaitanya Kulkarni wrote:

The barriers were added to the nvme_irq() in the
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
preventing  poll queues from mistakenly triggering the spurious
interrupt detection.

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

Would seem prudent to just ask the original submitter to send a v2
of his patch, as that's where it came from.

-- 
Jens Axboe


_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme