[PATCH net-next 2/4] net: dsa: add port fast ageing

[Vivien Didelot]

Today the DSA drivers are in charge of flushing the MAC addresses
associated to a port when its STP state changes from Learning or
Forwarding, to Disabled or Blocking or Listening.

This makes the drivers more complex and hides the generic switch logic.
Introduce a new optional port_fast_age operation to dsa_switch_ops, to
move this logic to the DSA layer and keep drivers simple.

Signed-off-by: Vivien Didelot <vivien.dide...@savoirfairelinux.com>
---
 include/net/dsa.h |  2 ++
 net/dsa/slave.c   | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 7556646..b122196 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -143,6 +143,7 @@ struct dsa_port {
        struct net_device       *netdev;
        struct device_node      *dn;
        unsigned int            ageing_time;
+       u8                      stp_state;
 };
 
 struct dsa_switch {
@@ -339,6 +340,7 @@ struct dsa_switch_ops {
        void    (*port_bridge_leave)(struct dsa_switch *ds, int port);
        void    (*port_stp_state_set)(struct dsa_switch *ds, int port,
                                      u8 state);
+       void    (*port_fast_age)(struct dsa_switch *ds, int port);
 
        /*
         * VLAN support
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index fd78d4c..6b1282c 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -71,8 +71,26 @@ static inline bool dsa_port_is_bridged(struct dsa_slave_priv 
*p)
 
 static void dsa_port_set_stp_state(struct dsa_switch *ds, int port, u8 state)
 {
+       struct dsa_port *dp = &ds->ports[port];
+
        if (ds->ops->port_stp_state_set)
                ds->ops->port_stp_state_set(ds, port, state);
+
+       if (ds->ops->port_fast_age) {
+               /* Fast age FDB entries or flush appropriate forwarding database
+                * for the given port, if we are moving it from Learning or
+                * Forwarding state, to Disabled or Blocking or Listening state.
+                */
+
+               if ((dp->stp_state == BR_STATE_LEARNING ||
+                    dp->stp_state == BR_STATE_FORWARDING) &&
+                   (state == BR_STATE_DISABLED ||
+                    state == BR_STATE_BLOCKING ||
+                    state == BR_STATE_LISTENING))
+                       ds->ops->port_fast_age(ds, port);
+       }
+
+       dp->stp_state = state;
 }
 
 static int dsa_slave_open(struct net_device *dev)
-- 
2.10.0