Re: [PATCH 4/7] blk-mq: when polling for IO, look for any completion

[Christoph Hellwig <hch@infradead.org>]

> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 52b1c97cd7c6..3ca00d712158 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -3266,9 +3266,7 @@ static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
>  	 *  0:	use half of prev avg
>  	 * >0:	use this specific value
>  	 */
> -	if (q->poll_nsec == -1)
> -		return false;
> -	else if (q->poll_nsec > 0)
> +	if (q->poll_nsec > 0)
>  		nsecs = q->poll_nsec;
>  	else
>  		nsecs = blk_mq_poll_nsecs(q, hctx, rq);

The above comment now doesn't match the code here as the -1 case
is handled elsewhere.

> +static int __blk_mq_poll(struct blk_mq_hw_ctx *hctx)
>  {
>  	struct request_queue *q = hctx->queue;
>  	long state;

Can you merge __blk_mq_poll into blk_mq_poll now that blk_mq_poll
is pretty trivial?

>  static void nvme_rdma_recv_done(struct ib_cq *cq, struct ib_wc *wc)
>  {
> -	__nvme_rdma_recv_done(cq, wc, -1);
> +	__nvme_rdma_recv_done(cq, wc);
>  }

__nvme_rdma_recv_done and nvme_rdma_recv_done can be merged now.

>  static int nvme_rdma_conn_established(struct nvme_rdma_queue *queue)
> @@ -1758,10 +1752,12 @@ static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx, unsigned int tag)
>  		struct ib_cqe *cqe = wc.wr_cqe;
>  
>  		if (cqe) {
> -			if (cqe->done == nvme_rdma_recv_done)
> -				found |= __nvme_rdma_recv_done(cq, &wc, tag);
> -			else
> +			if (cqe->done == nvme_rdma_recv_done) {
> +				__nvme_rdma_recv_done(cq, &wc);
> +				found++;
> +			} else {
>  				cqe->done(cq, &wc);
> +			}

And we should probably look into separate poll queues for RDMA as well
while we're at it.