Re: [RFC PATCH 3/7] blk-mq: stop to handle IO before hctx's all CPUs become offline

[Minwoo Im <minwoo.im.dev@gmail.com>]

On 19-07-12 10:47:22, Ming Lei wrote:
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index e5ef40c603ca..028c5d78e409 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2205,6 +2205,64 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
>  	return -ENOMEM;
>  }
>  
> +static bool blk_mq_count_inflight_rq(struct request *rq, void *data,
> +				     bool reserved)
> +{
> +	unsigned *count = data;
> +
> +	if ((blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT))
> +		(*count)++;
> +
> +	return true;
> +}
> +
> +unsigned blk_mq_tags_inflight_rqs(struct blk_mq_tags *tags)
> +{
> +	unsigned count = 0;
> +
> +	blk_mq_all_tag_busy_iter(tags, blk_mq_count_inflight_rq, &count);
> +
> +	return count;
> +}

Ming,

Maybe it can be static?

> +
> +static void blk_mq_drain_inflight_rqs(struct blk_mq_hw_ctx *hctx)
> +{
> +	while (1) {
> +		if (!blk_mq_tags_inflight_rqs(hctx->tags))
> +			break;
> +		msleep(5);
> +	}
> +}