[PATCH rfc 1/6] nvme-pci: Split __nvme_process_cq to poll and handle

[jthumshirn@suse.de (Johannes Thumshirn)]

On Wed, Oct 05, 2016@07:52:02PM +0300, Sagi Grimberg wrote:
> 
> > > +static int __nvme_process_cq(struct nvme_queue *nvmeq, int *tag)
> > > +{
> > > +	struct nvme_completion cqe;
> > > +	int consumed = 0;
> > > 
> > > -	}
> > > +	while (nvme_read_cqe(nvmeq, &cqe)) {
> > > +		nvme_handle_cqe(nvmeq, &cqe);
> > > 
> > > -	/* If the controller ignores the cq head doorbell and continuously
> > > -	 * writes to the queue, it is theoretically possible to wrap around
> > > -	 * the queue twice and mistakenly return IRQ_NONE.  Linux only
> > > -	 * requires that 0.1% of your interrupts are handled, so this isn't
> > > -	 * a big problem.
> > > -	 */
> > > -	if (head == nvmeq->cq_head && phase == nvmeq->cq_phase)
> > > -		return;
> > > +		if (tag && *tag == cqe.command_id) {
> > > +			*tag = -1;
> > > +			break;
> > > +		}
> > > +	}
> > > 
> > > -	if (likely(nvmeq->cq_vector >= 0))
> > > -		writel(head, nvmeq->q_db + nvmeq->dev->db_stride);
> > > -	nvmeq->cq_head = head;
> > > -	nvmeq->cq_phase = phase;
> > > +	if (consumed)
> > > +		nvme_ring_cq_doorbell(nvmeq);
> > > 
> > > -	nvmeq->cqe_seen = 1;
> > > +	return consumed;
> > >  }
> > 
> > Won't 'consumed' always be 0 here and we thus never call
> > nvme_ring_cq_doorbell()? Am I overlooking something here, or is this
> > just for preparation of later patches?
> 
> that incrementation was lost in a squash. I'll restore it in v2.

OK, sounds good.

Please add my 
Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>
to said v2.

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