Subject: Re: [PATCH net-next v2 06/12] netfilter: merge udpv[4,6]_net_init into udp_net_init

From: Pablo Neira Ayuso <[email-masked]>
Date: Tue, 19 Jun 2012 13:39:58 +0200

On Tue, Jun 19, 2012 at 04:08:31PM +0800, Gao feng wrote:
> 于 2012年06月16日 19:22, Pablo Neira Ayuso 写道:
> > On Sat, Jun 16, 2012 at 11:41:17AM +0800, Gao feng wrote:
> >> merge udpv4_net_init and udpv6_net_init into udp_net_init to
> >> reduce the redundancy codes.
> >>
> >> and use nf_proto_net.users to identify if it's the first time
> >> we use the nf_proto_net. when it's the first time,we will
> >> initialized it.
> >>
> >> Signed-off-by: Gao feng <[email-masked]>
> >> ---
> >>  net/netfilter/nf_conntrack_proto_udp.c |   56 ++++++++++---------------------
> >>  1 files changed, 18 insertions(+), 38 deletions(-)
> >>
> >> diff --git a/net/netfilter/nf_conntrack_proto_udp.c b/net/netfilter/nf_conntrack_proto_udp.c
> >> index 2b978e6..61bca4f 100644
> >> --- a/net/netfilter/nf_conntrack_proto_udp.c
> >> +++ b/net/netfilter/nf_conntrack_proto_udp.c
> >> @@ -270,52 +270,32 @@ static int udp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn)
> >>  	return 0;
> >>  }
> >>
> >> -static void udp_init_net_data(struct nf_udp_net *un)
> >> +static int udp_init_net(struct net *net, u_int16_t proto)
> >>  {
> >> -	int i;
> >> -#ifdef CONFIG_SYSCTL
> >> -	if (!un->pn.ctl_table) {
> >> -#else
> >> -	if (!un->pn.users++) {
> >> -#endif
> >> +	int ret;
> >> +	struct nf_udp_net *un = udp_pernet(net);
> >> +	struct nf_proto_net *pn = &un->pn;
> >> +
> >> +	if (!pn->users) {
> >> +		int i;
> >>  		for (i = 0; i < UDP_CT_MAX; i++)
> >>  			un->timeouts[i] = udp_timeouts[i];
> >>  	}
> >> -}
> >> -
> >> -static int udpv4_init_net(struct net *net, u_int16_t proto)
> >> -{
> >> -	int ret;
> >> -	struct nf_udp_net *un = udp_pernet(net);
> >> -	struct nf_proto_net *pn = (struct nf_proto_net *)un;
> >>
> >> -	udp_init_net_data(un);
> >> +	if (proto == AF_INET) {
> > 
> > I think we can remove that u_int16_t proto that I proposed to make
> > something like:
> > 
> > static int udp_kmemdup_compat_sysctl_table(struct nf_proto_net *pn)
> > {
> > #ifdef CONFIG_SYSCTL
> > #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
> >         struct nf_udp_net *un = (struct nf_udp_net *)pn;
> > +
> > +       if (pn->ctl_compat_table)
> > +               return 0;
> > +
> >         pn->ctl_compat_table = kmemdup(udp_compat_sysctl_table,
> >                                        sizeof(udp_compat_sysctl_table),
> >                                        GFP_KERNEL);
> >         if (!pn->ctl_compat_table)
> >                 return -ENOMEM;
> > 
> > That should be enough to ensure that the compat is registered once. No
> > matter if it's done by the IPv4 or IPv6 invocation of udp_init_net.
> > 
> > Thus, it will look consistent with udp_kmemdup_sysctl_table.
> 
> 
> yes, but this will be very terrible to unregister compat sysctl
> and free compat sysctl table.
> 
> thinking about, we may insmod nf_conntrack_ipv6 only, as your idea,
> we will allocate compat_sysctl_table.so we have to free it when
> rmmod nf_conntrack_ipv6.

You're right.

> in order to implement it, we have to change the logic of
> nf_ct_l4proto_unregister_sysctl and nf_ct_unregister_sysctl. because we
> only free the sysctl table when we unregister the proto.

OK, let's stick to what we have then.