Re: [PATCH RFC/RFT net-next v2 1/5] net: dsa: deny bridge VLAN with existing 8021q upper on any port

Simon Horman
2025-12-01T14:48:03Z

On Mon, Dec 01, 2025 at 11:28:13AM +0100, Jonas Gorski wrote:

...

> diff --git a/net/dsa/user.c b/net/dsa/user.c
> index f59d66f0975d..fa1fe0f1493a 100644
> --- a/net/dsa/user.c
> +++ b/net/dsa/user.c
> @@ -653,21 +653,30 @@ static int dsa_user_port_attr_set(struct net_device *dev, const void *ctx,
>
> /* Must be called under rcu_read_lock() */
> static int
> -dsa_user_vlan_check_for_8021q_uppers(struct net_device *user,
> +dsa_user_vlan_check_for_8021q_uppers(struct dsa_port *dp,
> const struct switchdev_obj_port_vlan *vlan)
> {
> - struct net_device *upper_dev;
> - struct list_head *iter;
> + struct dsa_switch *ds = dp->ds;
> + struct dsa_port *other_dp;
>
> - netdev_for_each_upper_dev_rcu(user, upper_dev, iter) {
> - u16 vid;
> + dsa_switch_for_each_user_port(other_dp, ds) {
> + struct net_device *user = other_dp->user;

Hi Jonas,

The AI robot is concerned that user may be NULL here.
And I can't convince myself that cannot be the case.

Could you take a look?

https://netdev-ai.bots.linux.dev/ai-review.html?id=3d47057e-e740-4b66-9d60-9ec2a7ee92a1#patch-0

> + struct net_device *upper_dev;
> + struct list_head *iter;
>
> - if (!is_vlan_dev(upper_dev))
> + if (!dsa_port_bridge_same(dp, other_dp))
> continue;
>
> - vid = vlan_dev_vlan_id(upper_dev);
> - if (vid == vlan->vid)
> - return -EBUSY;
> + netdev_for_each_upper_dev_rcu(user, upper_dev, iter) {
> + u16 vid;
> +
> + if (!is_vlan_dev(upper_dev))
> + continue;
> +
> + vid = vlan_dev_vlan_id(upper_dev);
> + if (vid == vlan->vid)
> + return -EBUSY;
> + }
> }
>
> return 0;

...