Re: [PATCH v4 net-next 05/11] net: bridge: add helper to replay VLANs installed on port

[Nikolay Aleksandrov]

On 23/03/2021 01:51, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> 
> Currently this simple setup with DSA:
> 
> ip link add br0 type bridge vlan_filtering 1
> ip link add bond0 type bond
> ip link set bond0 master br0
> ip link set swp0 master bond0
> 
> will not work because the bridge has created the PVID in br_add_if ->
> nbp_vlan_init, and it has notified switchdev of the existence of VLAN 1,
> but that was too early, since swp0 was not yet a lower of bond0, so it
> had no reason to act upon that notification.
> 
> We need a helper in the bridge to replay the switchdev VLAN objects that
> were notified since the bridge port creation, because some of them may
> have been missed.
> 
> As opposed to the br_mdb_replay function, the vg->vlan_list write side
> protection is offered by the rtnl_mutex which is sleepable, so we don't
> need to queue up the objects in atomic context, we can replay them right
> away.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> ---
>  include/linux/if_bridge.h | 10 ++++++
>  net/bridge/br_vlan.c      | 73 +++++++++++++++++++++++++++++++++++++++
>  2 files changed, 83 insertions(+)
> 

Same comments about the const qualifiers as the other patches.
The code looks good to me otherwise.

Acked-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>

> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> index b564c4486a45..2cc35038a8ca 100644
> --- a/include/linux/if_bridge.h
> +++ b/include/linux/if_bridge.h
> @@ -111,6 +111,8 @@ int br_vlan_get_pvid_rcu(const struct net_device *dev, u16 *p_pvid);
>  int br_vlan_get_proto(const struct net_device *dev, u16 *p_proto);
>  int br_vlan_get_info(const struct net_device *dev, u16 vid,
>  		     struct bridge_vlan_info *p_vinfo);
> +int br_vlan_replay(struct net_device *br_dev, struct net_device *dev,
> +		   struct notifier_block *nb, struct netlink_ext_ack *extack);
>  #else
>  static inline bool br_vlan_enabled(const struct net_device *dev)
>  {
> @@ -137,6 +139,14 @@ static inline int br_vlan_get_info(const struct net_device *dev, u16 vid,
>  {
>  	return -EINVAL;
>  }
> +
> +static inline int br_vlan_replay(struct net_device *br_dev,
> +				 struct net_device *dev,
> +				 struct notifier_block *nb,
> +				 struct netlink_ext_ack *extack)
> +{
> +	return -EOPNOTSUPP;
> +}
>  #endif
>  
>  #if IS_ENABLED(CONFIG_BRIDGE)
> diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
> index 8829f621b8ec..ca8daccff217 100644
> --- a/net/bridge/br_vlan.c
> +++ b/net/bridge/br_vlan.c
> @@ -1751,6 +1751,79 @@ void br_vlan_notify(const struct net_bridge *br,
>  	kfree_skb(skb);
>  }
>  
> +static int br_vlan_replay_one(struct notifier_block *nb,
> +			      struct net_device *dev,
> +			      struct switchdev_obj_port_vlan *vlan,
> +			      struct netlink_ext_ack *extack)
> +{
> +	struct switchdev_notifier_port_obj_info obj_info = {
> +		.info = {
> +			.dev = dev,
> +			.extack = extack,
> +		},
> +		.obj = &vlan->obj,
> +	};
> +	int err;
> +
> +	err = nb->notifier_call(nb, SWITCHDEV_PORT_OBJ_ADD, &obj_info);
> +	return notifier_to_errno(err);
> +}
> +
> +int br_vlan_replay(struct net_device *br_dev, struct net_device *dev,
> +		   struct notifier_block *nb, struct netlink_ext_ack *extack)
> +{
> +	struct net_bridge_vlan_group *vg;
> +	struct net_bridge_vlan *v;
> +	struct net_bridge_port *p;
> +	struct net_bridge *br;
> +	int err = 0;
> +	u16 pvid;
> +
> +	ASSERT_RTNL();
> +
> +	if (!netif_is_bridge_master(br_dev))
> +		return -EINVAL;
> +
> +	if (!netif_is_bridge_master(dev) && !netif_is_bridge_port(dev))
> +		return -EINVAL;
> +
> +	if (netif_is_bridge_master(dev)) {
> +		br = netdev_priv(dev);
> +		vg = br_vlan_group(br);
> +		p = NULL;
> +	} else {
> +		p = br_port_get_rtnl(dev);
> +		if (WARN_ON(!p))
> +			return -EINVAL;
> +		vg = nbp_vlan_group(p);
> +		br = p->br;
> +	}
> +
> +	if (!vg)
> +		return 0;
> +
> +	pvid = br_get_pvid(vg);
> +
> +	list_for_each_entry(v, &vg->vlan_list, vlist) {
> +		struct switchdev_obj_port_vlan vlan = {
> +			.obj.orig_dev = dev,
> +			.obj.id = SWITCHDEV_OBJ_ID_PORT_VLAN,
> +			.flags = br_vlan_flags(v, pvid),
> +			.vid = v->vid,
> +		};
> +
> +		if (!br_vlan_should_use(v))
> +			continue;
> +
> +		br_vlan_replay_one(nb, dev, &vlan, extack);
> +		if (err)
> +			return err;
> +	}
> +
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(br_vlan_replay);
> +
>  /* check if v_curr can enter a range ending in range_end */
>  bool br_vlan_can_enter_range(const struct net_bridge_vlan *v_curr,
>  			     const struct net_bridge_vlan *range_end)
>