Re: [patch]blk-mq: blk_mq_tag_to_rq should handle flush request

Christoph Hellwig
2014-06-04T11:11:35Z

On Fri, May 30, 2014 at 08:09:51AM -0600, Jens Axboe wrote:
> I have applied this one, but it irks me a little bit since we have
> to touch q->flush_rq->stuff from a potential hot path. I haven't
> thought much about this yet, but it would be a lot better if we
> could fold in the flush tag somehow.

This one also breaks scsi-mq by changing the first parameter of
blk_mq_tag_to_rq. With host-wide tags we won't have a hardware context
easily available when looking for a request by tag.