On Fri, 2021-07-02 at 17:23 +0200, Matthias Treydte wrote:
> Quoting Paolo Abeni <pabeni@xxxxxxxxxx>:
>
> > ---
> > diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
> > index 54e06b88af69..458c888337a5 100644
> > --- a/net/ipv4/udp_offload.c
> > +++ b/net/ipv4/udp_offload.c
> > @@ -526,6 +526,8 @@ struct sk_buff *udp_gro_receive(struct list_head
> > *head, struct sk_buff *skb,
> > if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
> > (sk && udp_sk(sk)->gro_enabled) ||
> > NAPI_GRO_CB(skb)->is_flist)
> > pp =
> > call_gro_receive(udp_gro_receive_segment, head, skb);
> > + else
> > + goto out;
> > return pp;
> > }
>
> Impressive! This patch, applied to 5.13, fixes the problem. What I
> like even more is that it again confirms my suspicion that an "if"
> without an "else" is always a code smell. :-)
Thank you for the quick feedback! I'll submit formally soon, after more
tests. I'll probably change the code to be something hopefully more
readable, as follow:
---
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 7a670757f37a..b3aabc886763 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -551,8 +551,10 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
if ((!sk && (skb->dev->features & NETIF_F_GRO_UDP_FWD)) ||
(sk && udp_sk(sk)->gro_enabled) || NAPI_GRO_CB(skb)->is_flist)
- pp = call_gro_receive(udp_gro_receive_segment, head, skb);
- return pp;
+ return call_gro_receive(udp_gro_receive_segment, head, skb);
+
+ /* no GRO, be sure flush the current packet */
+ goto out;
}
---
> With this and the reproducer in my previous mail, is there still value
> in doing the "perf" stuff?
Not needed, thank you!
Would be great instead if you could have a spin to the proposed variant
above - not stritly needed, I'm really asking for a few extra miles
here ;)
Cheers,
Paolo
