net: dsa: rollback bridging on error

When an error is returned during the bridging of a port in a
NETDEV_CHANGEUPPER event, net/core/dev.c rolls back the operation.

Be consistent and unassign dp->bridge_dev when this happens.

In the meantime, add comments to document this behavior.

Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 332eb23..d726307 100644 (file)
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -562,12 +562,21 @@ static int dsa_slave_bridge_port_join(struct net_device *dev,
        struct dsa_switch *ds = p->dp->ds;
        int ret = -EOPNOTSUPP;
 
+       /* Here the port is already bridged. Reflect the current configuration
+        * so that drivers can program their chips accordingly.
+        */
        p->dp->bridge_dev = br;
 
        if (ds->ops->port_bridge_join)
                ret = ds->ops->port_bridge_join(ds, p->dp->index, br);
 
-       return ret == -EOPNOTSUPP ? 0 : ret;
+       /* The bridging is rolled back on error */
+       if (ret && ret != -EOPNOTSUPP) {
+               p->dp->bridge_dev = NULL;
+               return ret;
+       }
+
+       return 0;
 }
 
 static void dsa_slave_bridge_port_leave(struct net_device *dev,
@@ -576,6 +585,9 @@ static void dsa_slave_bridge_port_leave(struct net_device *dev,
        struct dsa_slave_priv *p = netdev_priv(dev);
        struct dsa_switch *ds = p->dp->ds;
 
+       /* Here the port is already unbridged. Reflect the current configuration
+        * so that drivers can program their chips accordingly.
+        */
        p->dp->bridge_dev = NULL;
 
        if (ds->ops->port_bridge_leave)