Re: [PATCH RFC 4/5] nvme: add sysfs attribute to change IO timeout per nvme controller

[Mohamed Khalfella <mkhalfella@purestorage.com>]

On Fri 2026-02-20 13:47:08 +0100, Maurizio Lombardi wrote:
> On Thu Feb 19, 2026 at 6:22 PM CET, Maurizio Lombardi wrote:
> > On Wed Feb 18, 2026 at 6:54 PM CET, Mohamed Khalfella wrote:
> >
> > So changing the timeout field in the tagset should be doable, the
> > only problem is avoid racing against nvme_alloc_ns().
> >
> > I will try to come up with something.
> 
> I decided to keep the current design, calling blk_queue_rq_timeout()
> with the namespaces_lock mutex locked is the easiest solution
> 
> I am sending a V2 in a few moments.
> 

How about restricting changing io timeout to LIVE controllers only. This
will make the problem easier to solve. Maybe something like the below?

	enum nvme_ctrl_state state;
	unsigned long flags;

        spin_lock_irqsave(&ctrl->lock, flags);
	state = nvme_ctrl_state(ctrl);
	if (state != NVME_CTRL_LIVE) {
		spin_unlock_irqrestore(&ctrl->lock, flags);
		return -EBUSY
	}

	if (ctrl->queue_count > 1)
		WRITE_ONCE(ctrl->tagset->timeout, timeout);
	spin_unlock_irqrestore(&ctrl->lock, flags);

	/* Take the namespaces_lock to avoid racing against nvme_alloc_ns() */
	mutex_lock(&ctrl->namespaces_lock);

	ctrl->io_timeout = msecs_to_jiffies(timeout);
	list_for_each_entry(ns, &ctrl->namespaces, list)
		blk_queue_rq_timeout(ns->queue, ctrl->io_timeout);

	mutex_unlock(&ctrl->namespaces_lock);


> Maurizio
>