On 2021-01-13 12:10, Alexander Duyck wrote:
> On 1/12/21 1:16 PM, Alexander Lobakin wrote:
> > Commit 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") actually
> > not only added a support for fraglisted UDP GRO, but also tweaked
> > some logics the way that non-fraglisted UDP GRO started to work for
> > forwarding too.
> > Tests showed that currently forwarding and NATing of plain UDP GRO
> > packets are performed fully correctly, regardless if the target
> > netdevice has a support for hardware/driver GSO UDP L4 or not.
> > Add the last element and allow to form plain UDP GRO packets if
> > there is no socket -> we are on forwarding path.
> >Your patch is very similar with the RFC what I submitted but has different approach. My concern was NAT forwarding. https://lore.kernel.org/patchwork/patch/1362257/ Nevertheless, I agreed with your idea that allow fraglisted UDP GRO if there is socket. > > Plain UDP GRO forwarding even shows better performance than fraglisted > > UDP GRO in some cases due to not wasting one skbuff_head per every > > segment. > > > > Signed-off-by: Alexander Lobakin <aloba...@pm.me> > > --- > > net/ipv4/udp_offload.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c > > index ff39e94781bf..9d71df3d52ce 100644 > > --- a/net/ipv4/udp_offload.c > > +++ b/net/ipv4/udp_offload.c > > @@ -460,12 +460,13 @@ struct sk_buff *udp_gro_receive(struct list_head > > *head, struct sk_buff *skb, > > if (skb->dev->features & NETIF_F_GRO_FRAGLIST) > > NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1; is_flist can be true even if !sk. > > > > - if ((sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist) { > > + if (!sk || (sk && udp_sk(sk)->gro_enabled) || Actually sk would be NULL by udp_encap_needed_key in udp4_gro_receive or udp6_gro_receive. > > + NAPI_GRO_CB(skb)->is_flist) { > > pp = call_gro_receive(udp_gro_receive_segment, head, skb); udp_gro_receive_segment will check is_flist first and try to do fraglisted UDP GRO. Can you check what I'm missing? > > return pp; > > } > > > > The second check for sk in "(sk && udp_sk(sk)->gro_enabled)" is > redundant and can be dropped. You already verified it is present when > you checked for !sk before the logical OR. > Sorry, Alexander Duyck. I believe Alexander Lobakin will answer this. > > - if (!sk || NAPI_GRO_CB(skb)->encap_mark || > > + if (NAPI_GRO_CB(skb)->encap_mark || > > (skb->ip_summed != CHECKSUM_PARTIAL && > > NAPI_GRO_CB(skb)->csum_cnt == 0 && > > !NAPI_GRO_CB(skb)->csum_valid) || > >
