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

[Jon Derrick]

Looks good assuming you will restore the increment in v2!

Acked-by Jon Derrick: <jonathan.derrick at intel.com>

On Wed, Oct 05, 2016 at 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.
> 
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