since we should only care about ownership at probe, hotplug, and otherIt has to be locked against concurrent probe, and there isn't
places well outside critical fast-paths, I'm not sure we really need to keep
track of that anyway - it can always be recalculated by walking the
group->devices list,
currently any locking scheme that can support this. The owner_cnt is
effectively a new lock for this purpose. It is the same issue we
talked about with that VFIO patch you showed me.
So, using the group->device_list would require adding something else
somewhere - which I think should happen when someone has
justification for another use of whatever that something else is.