Re: [PATCH 3/3] blk-mq: centralise related handling into blk_mq_get_driver_tag

[Christoph Hellwig <hch@infradead.org>]

> index 21108a550fbf..3b0c5cfe922a 100644
> --- a/block/blk-flush.c
> +++ b/block/blk-flush.c
> @@ -236,12 +236,10 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
>  		error = fq->rq_status;
>  
>  	hctx = flush_rq->mq_hctx;
> +	if (!q->elevator)
>  		flush_rq->tag = -1;
> +	else
>  		flush_rq->internal_tag = -1;

These should switch to BLK_MQ_NO_TAG which you're at it.

> -	if (!(data->flags & BLK_MQ_REQ_INTERNAL))
> -		blk_mq_tag_busy(data->hctx);

BLK_MQ_REQ_INTERNAL is gone now, so this won't apply.

>  static bool blk_mq_get_driver_tag(struct request *rq)
>  {
> +	struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
> +	bool shared = blk_mq_tag_busy(rq->mq_hctx);
> +
> +	if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq))
> +		return false;
> +
> +	if (shared) {
> +		rq->rq_flags |= RQF_MQ_INFLIGHT;
> +		atomic_inc(&hctx->nr_active);
> +	}
> +	hctx->tags->rqs[rq->tag] = rq;
> +	return true;
>  }

The function seems a bit misnamed now, although I don't have a good
suggestion for a better name.