netdev - Re: [RFC PATCH v2 01/10] udp: implement complete book-keeping for encap

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Date:   Thu, 25 Oct 2018 15:00:09 +0200
From:   Paolo Abeni <pabeni@...hat.com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>
Cc:     Network Development <netdev@...r.kernel.org>,
        Willem de Bruijn <willemb@...gle.com>,
        steffen.klassert@...unet.com
Subject: Re: [RFC PATCH v2 01/10] udp: implement complete book-keeping for
 encap_needed

Hi,

I'm sorry for lagging behind, this one felt outside my radar.

On Mon, 2018-10-22 at 12:06 -0400, Willem de Bruijn wrote:
> @@ -2431,7 +2435,9 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
> >                         /* FALLTHROUGH */
> >                 case UDP_ENCAP_L2TPINUDP:
> >                         up->encap_type = val;
> > -                       udp_encap_enable();
> > +                       if (!up->encap_enabled)
> > +                               udp_encap_enable();
> > +                       up->encap_enabled = 1;
> 
> nit: no need for the branch: udp_encap_enable already has a branch and
> is static inline.

Uhm... I think it's needed, so that we call udp_encap_enable() at most
once per socket. If up->encap_enabled we also call static_key_disable
at socket destruction time (once per socket, again) and hopefully we
don't "leak" static_key_enable invocation.

> Perhaps it makes sense to convert that to take the udp_sock and handle
> the state change within, to avoid having to open code at multiple
> locations.

Possibly calling directly udp_tunnel_encap_enable()? that additionally
cope with ipv6, which is not needed here, but should not hurt.

Cheers,

Paolo