On Wed, Jun 01, 2022 at 03:09:26PM +0800, Ming Lei wrote:
> > Yes, we probably need a blk_mq_quiesce_queue call like in the incremental
> > patch below. Do you have any good reproducer, though?
>
> blktests block/027 should cover this.
That did not trigger the problem for me.
> > if (q->elevator) {
> > + blk_mq_quiesce_queue(q);
> > +
> > mutex_lock(&q->sysfs_lock);
> > elevator_exit(q);
> > mutex_unlock(&q->sysfs_lock);
> > +
> > + blk_mq_unquiesce_queue(q);
> > }
> >
>
> I am afraid the above way may slow down disk shutdown a lot, see
> the following commit, that is also the reason why I moved it into disk
> release handler, when any sync io submission are done.
SCSI devices that are just probed and never had a disk attached will
not have q->elevator set and not hit this quiesce at all.
