Re: [PATCH net-next 4/4] net: dsa: don't set skb->offload_fwd_mark when not offloading the bridge

[George McCollister <george.mccollister@gmail.com>]

On Sun, Feb 14, 2021 at 9:54 AM Vladimir Oltean <olteanv@gmail.com> wrote:
[snip]
> diff --git a/net/dsa/tag_xrs700x.c b/net/dsa/tag_xrs700x.c
> index 858cdf9d2913..215ecceea89e 100644
> --- a/net/dsa/tag_xrs700x.c
> +++ b/net/dsa/tag_xrs700x.c
> @@ -45,8 +45,7 @@ static struct sk_buff *xrs700x_rcv(struct sk_buff *skb, struct net_device *dev,
>         if (pskb_trim_rcsum(skb, skb->len - 1))
>                 return NULL;
>
> -       /* Frame is forwarded by hardware, don't forward in software. */
> -       skb->offload_fwd_mark = 1;
> +       dsa_default_offload_fwd_mark(skb);

Does it make sense that the following would have worked prior to this
change? Is this only an issue for bridging between DSA ports when
offloading is supported? lan0 is a port an an xrs700x switch:

ip link set eth0 up
ip link del veth0
ip link add veth0 type veth peer name veth1

for eth in veth0 veth1 lan1; do
    ip link set ${eth} up
done
ip link add br0 type bridge
ip link set veth1 master br0
ip link set lan1 master br0
ip link set br0 up

ip addr add 192.168.2.1/24 dev veth0

# ping host connected to physical LAN that lan0 is on
ping 192.168.2.249 (works!)

I was trying to come up with a way to test this change and expected
this would fail (and your patch) would fix it based on what you're
described.

-George

>
>         return skb;
>  }
> --
> 2.25.1
>