From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cong Wang <amwang@redhat.com>
Subject: Re: [Patch net-next] ipv6: separate out procfs code from mcast.c
Date: Wed, 24 Apr 2013 11:29:41 +0800
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Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org,
	yoshfuji@linux-ipv6.org
To: =?ISO-8859-1?Q?Bj=F8rn?= Mork <bjorn@mork.no>
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On Tue, 2013-04-23 at 14:33 +0200, Bj=C3=B8rn Mork wrote:
> Cong Wang <amwang@redhat.com> writes:
>=20
> > On Tue, 2013-04-23 at 03:36 -0400, David Miller wrote:
> >> From: Cong Wang <amwang@redhat.com>
> >> Date: Tue, 23 Apr 2013 15:30:20 +0800
> >>=20
> >> > This is hard to do, as in the email I replied to Stephen. So I
> >> > prefer to just add a Kconfig dependency, at least for now.
> >>=20
> >> A Kconfig hack is exactly what I've told you is an unacceptable
> >> solution.
> >
> > Please enlighten me for a third solution. :)
>=20
> This is an completely untested idea....
>=20
> I note that vxlan_init_net requires a successful sock_create_kern().
> That implies a request_module("net-pf-...") followed by try_module_ge=
t.
>=20
> So if the sock_create_kern(PF_INET6, ..) succeeds then you *know* you
> have IPv6. If it fails with -EAFNOSUPPORT, then you could fall back t=
o
> sock_create_kern(PF_INET, ..) and set a flag indicating that runtime
> IPv6 support is disabled.  Then use this flag to allow/deny configuri=
ng
> any IPv6 destinations.

Excellent point! You are certainly right. I will give it a try.

>=20
> You may also have to protect the IPv6 modular symbols you use with
> symbol_request() or similar to prevent vxlan from depending on IPv6. =
 I
> dunno...
>=20

This sounds a bit crazy.