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

[Sagi Grimberg]

>> +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.