Re: [PATCH v5 net-next 07/15] net: bridge: mst: Add helper to map an MSTI to a VID set

[Vladimir Oltean <olteanv@gmail.com>]

On Wed, Mar 16, 2022 at 04:08:49PM +0100, Tobias Waldekranz wrote:
> br_mst_get_info answers the question: "On this bridge, which VIDs are
> mapped to the given MSTI?"
> 
> This is useful in switchdev drivers, which might have to fan-out
> operations, relating to an MSTI, per VLAN.
> 
> An example: When a port's MST state changes from forwarding to
> blocking, a driver may choose to flush the dynamic FDB entries on that
> port to get faster reconvergence of the network, but this should only
> be done in the VLANs that are managed by the MSTI in question.
> 
> Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
> ---

Reviewed-by: Vladimir Oltean <olteanv@gmail.com>

>  include/linux/if_bridge.h |  7 +++++++
>  net/bridge/br_mst.c       | 26 ++++++++++++++++++++++++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
> index 3aae023a9353..1cf0cc46d90d 100644
> --- a/include/linux/if_bridge.h
> +++ b/include/linux/if_bridge.h
> @@ -119,6 +119,7 @@ int br_vlan_get_info(const struct net_device *dev, u16 vid,
>  		     struct bridge_vlan_info *p_vinfo);
>  int br_vlan_get_info_rcu(const struct net_device *dev, u16 vid,
>  			 struct bridge_vlan_info *p_vinfo);
> +int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids);
>  #else
>  static inline bool br_vlan_enabled(const struct net_device *dev)
>  {
> @@ -151,6 +152,12 @@ static inline int br_vlan_get_info_rcu(const struct net_device *dev, u16 vid,
>  {
>  	return -EINVAL;
>  }
> +
> +static inline int br_mst_get_info(const struct net_device *dev, u16 msti,
> +				  unsigned long *vids)
> +{
> +	return -EINVAL;
> +}
>  #endif
>  
>  #if IS_ENABLED(CONFIG_BRIDGE)
> diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
> index 00935a19afcc..00b36e629224 100644
> --- a/net/bridge/br_mst.c
> +++ b/net/bridge/br_mst.c
> @@ -13,6 +13,32 @@
>  
>  DEFINE_STATIC_KEY_FALSE(br_mst_used);
>  
> +int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids)
> +{
> +	const struct net_bridge_vlan_group *vg;
> +	const struct net_bridge_vlan *v;
> +	const struct net_bridge *br;
> +
> +	ASSERT_RTNL();
> +
> +	if (!netif_is_bridge_master(dev))
> +		return -EINVAL;
> +
> +	br = netdev_priv(dev);
> +	if (!br_opt_get(br, BROPT_MST_ENABLED))
> +		return -EINVAL;
> +
> +	vg = br_vlan_group(br);
> +
> +	list_for_each_entry(v, &vg->vlan_list, vlist) {
> +		if (v->msti == msti)
> +			__set_bit(v->vid, vids);
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(br_mst_get_info);
> +
>  static void br_mst_vlan_set_state(struct net_bridge_port *p, struct net_bridge_vlan *v,
>  				  u8 state)
>  {
> -- 
> 2.25.1
>