Re: [PATCH] vlan: enable GRO if real_dev supports it

Ben Hutchings
2010-09-15T17:24:41Z

On Wed, 2010-09-15 at 10:14 -0700, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Wed, 15 Sep 2010 19:08:40 +0200
>
> > Le mercredi 15 septembre 2010 à 09:37 -0700, Brandon Philips a écrit :
> >> Currently vlan devices don't have GRO by default as none of the Ethernet
> >> drivers add NETIF_F_GRO to their vlan_features.
> >>
> >> As GRO is a software feature just propogate GRO from the real_dev in the
> >> vlan core. There is no need to have the drivers each add NETIF_F_GRO to
> >> their vlan_features.
> >>
> >> Signed-off-by: Brandon Philips <bphilips@suse.de>
> >> ---
> >> net/8021q/vlan_dev.c | 1 +
> >> 1 files changed, 1 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
> >> index 3bccdd1..6fbc445 100644
> >> --- a/net/8021q/vlan_dev.c
> >> +++ b/net/8021q/vlan_dev.c
> >> @@ -735,6 +735,7 @@ static int vlan_dev_init(struct net_device *dev)
> >> (1<<__LINK_STATE_DORMANT))) |
> >> (1<<__LINK_STATE_PRESENT);
> >>
> >> + dev->features |= real_dev->features & NETIF_F_GRO;
> >> dev->features |= real_dev->features & real_dev->vlan_features;
> >> dev->gso_max_size = real_dev->gso_max_size;
> >>
> >
> > Hmm, this is only part of a generic solution.
> >
> > If I enable gro with "ethtool -K eth0 gro on", should we propagate GRO
> > on vlan eth0.555 ?
>
> I think a better way to implement this is to set NETIF_F_GRO in
> netdev->vlan_features at register_netdev() time if it is set in
> netdev->features
>
> That is the implementation I was implying earlier in this thread.

We can even add it unconditionally there, since we only ever use
dev->features & dev->vlan_features.

Ben.

--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.