net: bridge: mst: Add helper to query a port's MST state

This is useful for switchdev drivers who are offloading MST states
into hardware. As an example, a driver may wish to flush the FDB for a
port when it transitions from forwarding to blocking - which means
that the previous state must be discoverable.

Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index 4efd554..d62ef42 100644 (file)
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -121,6 +121,7 @@ int br_vlan_get_info_rcu(const struct net_device *dev, u16 vid,
                         struct bridge_vlan_info *p_vinfo);
 bool br_mst_enabled(const struct net_device *dev);
 int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids);
+int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state);
 #else
 static inline bool br_vlan_enabled(const struct net_device *dev)
 {
@@ -164,6 +165,11 @@ static inline int br_mst_get_info(const struct net_device *dev, u16 msti,
 {
        return -EINVAL;
 }
+static inline int br_mst_get_state(const struct net_device *dev, u16 msti,
+                                  u8 *state)
+{
+       return -EINVAL;
+}
 #endif
 
 #if IS_ENABLED(CONFIG_BRIDGE)

diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c
index 830a574..ee680ad 100644 (file)
--- a/net/bridge/br_mst.c
+++ b/net/bridge/br_mst.c
@@ -48,6 +48,31 @@ int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids)
 }
 EXPORT_SYMBOL_GPL(br_mst_get_info);
 
+int br_mst_get_state(const struct net_device *dev, u16 msti, u8 *state)
+{
+       const struct net_bridge_port *p = NULL;
+       const struct net_bridge_vlan_group *vg;
+       const struct net_bridge_vlan *v;
+
+       ASSERT_RTNL();
+
+       p = br_port_get_check_rtnl(dev);
+       if (!p || !br_opt_get(p->br, BROPT_MST_ENABLED))
+               return -EINVAL;
+
+       vg = nbp_vlan_group(p);
+
+       list_for_each_entry(v, &vg->vlan_list, vlist) {
+               if (v->brvlan->msti == msti) {
+                       *state = v->state;
+                       return 0;
+               }
+       }
+
+       return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(br_mst_get_state);
+
 static void br_mst_vlan_set_state(struct net_bridge_port *p, struct net_bridge_vlan *v,
                                  u8 state)
 {