Re: [PATCH V11 07/12] blk-mq: stop to handle IO and drain IO before hctx becomes inactive

[Bart Van Assche <bvanassche@xxxxxxx>]

On 2020-05-13 04:59, Christoph Hellwig wrote:
>> +	if (unlikely(direct_issue && rq->mq_ctx->cpu != raw_smp_processor_id()))
>> +		smp_mb();
>> +	else
>> +		barrier();
> 
> Independ of the fact that I still think this is horrible and hacky,
> I also still don't see what the barrier() is trying to help with.

I'm also less than enthusiast about this code.

Bart.