Re: [PATCH 1/4] block: have plug stored requests hold references to the queue

[Jens Axboe <axboe@xxxxxxxxx>]

On 11/4/21 3:01 AM, Christoph Hellwig wrote:
>> @@ -1643,7 +1643,7 @@ void blk_flush_plug(struct blk_plug *plug, bool from_schedule)
>>  		flush_plug_callbacks(plug, from_schedule);
>>  	if (!rq_list_empty(plug->mq_list))
>>  		blk_mq_flush_plug_list(plug, from_schedule);
>> -	if (unlikely(!from_schedule && plug->cached_rq))
>> +	if (unlikely(!rq_list_empty(plug->cached_rq)))
> 
> How is this related to the rest of the patch?

With references to the requests, flushing them even from a schedule
unplug condition is a lot saner in case someone is waiting on the
queue to quiesce.

-- 
Jens Axboe