On Thu, Feb 09, 2017 at 12:04:26PM -0700, Jason Gunthorpe wrote:
Jarkko Sakkinen <jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> wrote on 02/10/2017
03:48:37 AM:

> > This series should focus on allowing a user space RM to co-exist with
> > the in-kernel services - lets try and tackle the idea of a
> > policy-restricted or unpriv-safe cdev when someone comes up with a
> > comprehensive proposal..

First, does "coexist" mean in series (two layers of RM) or in parallel
(both
have simultaneous access).

Or does "in-kernel services" not include an RM?

Assuming in series, it will complicate the lower RM.  The main issue,
as always, is session context.  If you permit the upper RM to save context,
the lower RM has to track the mapping, because the lower layer can
alter the saved session context (regapping).