From: Johannes Berg <johannes@sipsolutions.net>
Date: Tue, 19 Nov 2013 15:19:30 +0100

The generic netlink multicast group registration doesn't have to
be dynamic, and can thus be simplified just like I did with the
ops. This removes some complexity in registration code.

Additionally, two users of generic netlink already use multicast
groups in a wrong way, add workarounds for those two to keep the
userspace API working, but at the same time make them not clash
with other users of multicast groups as might happen now.

While making it all a bit easier, also prevent such abuse by adding
checks to the APIs so each family can only use the groups it owns.

This looks great, and makes the unfortunate multicast ID handling in
DM and elsewhere explicit, controlled, and validated.

Series applied, thanks.