nvme/pcie hot plug results in /dev name change

[Keith Busch]

On Mon, Feb 13, 2023 at 04:01:03PM +0200, Sagi Grimberg wrote:
> > Also not sure if this is going to work out, but it looks like a good start to
> > me.
> > 
> > Instead of user pinning the virtual device so that it never goes away though, I
> > considered a user tunable "device missing delay" parameter to debounce link
> > events. New IOs would be deferred to the requeue_list while the timer is
> > active, and then EIO'ed if the timer expires without a successful LIVE
> > controller attachment. The use cases I'm considering are short bounces from
> > transient link resets, so I'd expect timers to be from a few seconds to maybe a
> > minute.
> 
> Isn't this equivalent to dm-mpath queue_if_no_path or no_path_timeout ?

Similiar, but generic to non-multipath devices.
 
> We can keep the mpath device around, but if not, what is the desired
> behavior from the upper layers?

I don't think we're looking for any behavioral changes in the upper layers.