On 11/29/18 8:45 AM, Christoph Hellwig wrote:
> On Wed, Nov 28, 2018 at 06:35:33AM -0700, Jens Axboe wrote:
>> blk-mq passes information to the hardware about any given request being
>> the last that we will issue in this sequence. The point is that hardware
>> can defer costly doorbell type writes to the last request. But if we run
>> into errors issuing a sequence of requests, we may never send the request
>> with bd->last == true set. For that case, we need a hook that tells the
>> hardware that nothing else is coming right now.
>>
>> For failures returned by the drivers ->queue_rq() hook, the driver is
>> responsible for flushing pending requests, if it uses bd->last to
>> optimize that part. This works like before, no changes there.
>>
>> Reviewed-by: Omar Sandoval
>> Reviewed-by: Ming Lei
>> Reviewed-by: Christoph Hellwig
>
> I don't think I actually reviewed it before in this form.
>
> But now that I took a look it does indeed look fine to me:
>
> Reviewed-by: Christoph Hellwig
Only change is moving those two hunks from the later patch into this
one, so it isn't an empty declaration.
--
Jens Axboe
