On Sat, 2017-12-02 at 08:36 +0800, Ming Lei wrote:
> On Fri, Dec 01, 2017 at 07:52:14PM +0000, Bart Van Assche wrote:
> > On Fri, 2017-12-01 at 10:58 +0800, Ming Lei wrote:
> > > On Thu, Nov 30, 2017 at 04:08:45PM -0800, Bart Van Assche wrote:
> > > > blk_mq_dispatch_rq_list() is called. Make sure that
> > > > BLK_MQ_S_SCHED_RESTART is set before any blk_mq_dispatch_rq_list()
> > > > call occurs.
> > > >
> > > > Fixes: commit b347689ffbca ("blk-mq-sched: improve dispatching from sw
> > > > queue")
> > >
> > > We always mark RESTART state bit just before dispatching from
> > > ->dispatch_list,
> > > this way has been there before b347689ffbca, which doesn't change this
> > > RESTART mechanism, so please explain a bit why it is a fix on commit
> > > b347689ffbca.
> >
> > I'm not completely sure which patch introduced the lockup fixed by this
> > patch
> > but I will have another look whether this was really introduced by commit
> > b347689ffbca.
>
> Please make sure 'Fixes' tag correct.
Further tests have shown that the lockup I referred to does not occur before
commit
b347689ffbca but that it occurs with b347689ffbca. I think that shows clearly
that
commit b347689ffbca introduced this lockup.
Bart.
