> On 09/27/2016 09:31 AM, Steve Wise wrote:
> >> @@ -2079,11 +2075,15 @@ EXPORT_SYMBOL_GPL(nvme_kill_queues);
> >> void nvme_stop_queues(struct nvme_ctrl *ctrl)
> >> {
> >> struct nvme_ns *ns;
> >> + struct request_queue *q;
> >>
> >> mutex_lock(&ctrl->namespaces_mutex);
> >> list_for_each_entry(ns, &ctrl->namespaces, list) {
> >> - blk_mq_cancel_requeue_work(ns->queue);
> >> - blk_mq_stop_hw_queues(ns->queue);
> >> + q = ns->queue;
> >> + blk_quiesce_queue(q);
> >> + blk_mq_cancel_requeue_work(q);
> >> + blk_mq_stop_hw_queues(q);
> >> + blk_resume_queue(q);
> >> }
> >> mutex_unlock(&ctrl->namespaces_mutex);
> >
> > Hey Bart, should nvme_stop_queues() really be resuming the blk queue?
>
> Hello Steve,
>
> Would you perhaps prefer that blk_resume_queue(q) is called from
> nvme_start_queues()? I think that would make the NVMe code harder to
> review.
I'm still learning the blk code (and nvme code :)), but I would think
blk_resume_queue() would cause requests to start being submit on the NVME
queues, which I believe shouldn't happen when they are stopped. I'm currently
debugging a problem where requests are submitted to the nvme-rdma driver while
it has supposedly stopped all the nvme and blk mqs. I tried your series at
Christoph's request to see if it resolved my problem, but it didn't.
> The above code won't cause any unexpected side effects if an
> NVMe namespace is removed after nvme_stop_queues() has been called and
> before nvme_start_queues() is called. Moving the blk_resume_queue(q)
> call into nvme_start_queues() will only work as expected if no
> namespaces are added nor removed between the nvme_stop_queues() and
> nvme_start_queues() calls. I'm not familiar enough with the NVMe code to
> know whether or not this change is safe ...
>
I'll have to look and see if new namespaces can be added/deleted while a nvme
controller is in the RECONNECTING state. In the meantime, I'm going to move
the blk_resume_queue() to nvme_start_queues() and see if it helps my problem.
Christoph: Thoughts?
Steve.
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