On Wed 08-03-17 09:00:09, Goldwyn Rodrigues wrote:
>
>
> On 03/08/2017 01:03 AM, Sagi Grimberg wrote:
> >
> >> - if (likely(blk_queue_enter(q, false) == 0)) {
> >> + if (likely(blk_queue_enter(q, bio_flagged(bio, BIO_NOWAIT))
> >> == 0)) {
> >> ret = q->make_request_fn(q, bio);
> >
> > I think that for ->make_request to not block we'd need to set
> > BLK_MQ_REQ_NOWAIT in blk_mq_alloc_data to avoid blocking on a tag
> > allocation.
> >
> > Something like the untested addition below:
>
> I did that in the first series, but there are too many reasons to block
> in blk-mq [1]. I dropped blk-mq work in v2.
>
> [1] https://patchwork.kernel.org/patch/9571051/
Well, that's not really good. If we cannot support this for both blk-mq and
legacy block layer the feature will not be usable. So please work on blk-mq
support as well.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
