On Mon, 2007-07-02 at 16:48 +0200, Johannes Berg wrote:

If I find time I might
actually fix the unregistration bug too, but I have a feeling digging in
the socket code might take more time than I have right now.

Hmm. I started digging into the af_netlink.c code and realised that the
whole thing I've been doing cannot possibly work completely since the
genl socket is created with GENL_MAX_ID as the "groups" parameter to
netlink_kernel_create() and that limits the groups, and the af_netlink
code really wants to know the number of groups up-front.

So some deeper surgery is required to lift the limit of 1023 multicast
group now. Not that I like the current genetlink code, we allocate 256
bytes for the in-kernel socket just for the listeners bitmap, and just
as many for each socket's groups bitmaps while it's unlikely a regular
system right now will ever reach that limit.

I'll be posting some patches as replies.

johannes