Re: [PATCH v2 3/3] nvme: fire discovery log page change events to userspace

[Christoph Hellwig]

On Thu, Aug 29, 2019 at 11:21:02AM -0700, Sagi Grimberg wrote:
>> Yes we do, userspace should use it to order events.  Does udev not
>> handle that properly today?
>
> The problem is not ordering of events, its really about the fact that
> the chardev can be removed and reallocated for a different controller
> (could be a completely different discovery controller) by the time
> that userspace handles the event.

The same is generally true for lot of kernel devices.  We could reduce
the chance by using the idr cyclic allocator.