On Sat, Mar 9, 2019 at 9:26 AM Christian Brauner [off-list ref] wrote:

Aside from that I want to point out that it is non-trivial to do this in
user space.

Oh, absolutely agreed. It's easy to do it in the kernel, and doing it
anywhere else ends up having horrible races that the kernel has to
deal with and has long solved anyway.

I've only seen this (2/5) patch, so I won't comment on the other ones,
but this still makes sense to me.

Al, comments?

                  Linus