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 <osandov@xxxxxx> > Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx> > Reviewed-by: Christoph Hellwig <hch@xxxxxx> 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 <hch@xxxxxx>
