# Re: \[RFC PATCH v2 net-next 15/16\] net: dsa: return -EOPNOTSUPP when driver does not implement .port\_lag\_join

- From: Florian Fainelli \<f.fainelli@gmail.com\>
- Date: 2021-03-22 15:52:47 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/03/6310852
- Thread: https://ratatoskr.run/netdev/2021/03/6306967/t.md

```text


On 3/18/2021 4:18 PM, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
> 
> The DSA core has a layered structure, and even though we end up
> returning 0 (success) to user space when setting a bonding/team upper
> that can't be offloaded, some parts of the framework actually need to
> know that we couldn't offload that.
> 
> For example, if dsa_switch_lag_join returns 0 as it currently does,
> dsa_port_lag_join has no way to tell a successful offload from a
> software fallback, and it will call dsa_port_bridge_join afterwards.
> Then we'll think we're offloading the bridge master of the LAG, when in
> fact we're not even offloading the LAG. In turn, this will make us set
> skb->offload_fwd_mark = true, which is incorrect and the bridge doesn't
> like it.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian
```