Re: [PATCH 1/2] nvme: pci: simplify timeout handling

Ming Lei
2018-05-10T21:53:22Z

On Thu, May 10, 2018 at 03:44:41PM -0600, Keith Busch wrote:
> On Fri, May 11, 2018 at 05:24:46AM +0800, Ming Lei wrote:
> > Could you share me the link?
>
> The diff was in this reply here:
>
> http://lists.infradead.org/pipermail/linux-nvme/2018-April/017019.html
>
> > Firstly, the previous nvme_sync_queues() won't work reliably, so this
> > patch introduces blk_unquiesce_timeout() and blk_quiesce_timeout() for
> > this purpose.
> >
> > Secondly, I remembered that you only call nvme_sync_queues() at the
> > entry of nvme_reset_work(), but timeout(either admin or normal IO)
> > can happen again during resetting, that is another race addressed by
> > this patchset, but can't cover by your proposal.
>
> I sync the queues at the beginning because it ensures there is not
> a single in flight request for the entire controller (all namespaces
> plus admin queue) before transitioning to the connecting state.
>
> If a command times out during connecting state, we go to the dead state.

Actually, it is hang forever in blk_mq_freeze_queue_wait() from
nvme_reset_dev(), not a dead state of controller.

Thanks,
Ming