bridge: notify enslaved devices of headroom changes

On bridge needed_headroom changes, the enslaved devices are
notified via the ndo_set_rx_headroom method

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index b37a1cc..a73df33 100644 (file)
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -223,6 +223,31 @@ static void destroy_nbp_rcu(struct rcu_head *head)
        destroy_nbp(p);
 }
 
+static unsigned get_max_headroom(struct net_bridge *br)
+{
+       unsigned max_headroom = 0;
+       struct net_bridge_port *p;
+
+       list_for_each_entry(p, &br->port_list, list) {
+               unsigned dev_headroom = netdev_get_fwd_headroom(p->dev);
+
+               if (dev_headroom > max_headroom)
+                       max_headroom = dev_headroom;
+       }
+
+       return max_headroom;
+}
+
+static void update_headroom(struct net_bridge *br, int new_hr)
+{
+       struct net_bridge_port *p;
+
+       list_for_each_entry(p, &br->port_list, list)
+               netdev_set_rx_headroom(p->dev, new_hr);
+
+       br->dev->needed_headroom = new_hr;
+}
+
 /* Delete port(interface) from bridge is done in two steps.
  * via RCU. First step, marks device as down. That deletes
  * all the timers and stops new packets from flowing through.
@@ -248,6 +273,9 @@ static void del_nbp(struct net_bridge_port *p)
        br_ifinfo_notify(RTM_DELLINK, p);
 
        list_del_rcu(&p->list);
+       if (netdev_get_fwd_headroom(dev) == br->dev->needed_headroom)
+               update_headroom(br, get_max_headroom(br));
+       netdev_reset_rx_headroom(dev);
 
        nbp_vlan_flush(p);
        br_fdb_delete_by_port(br, p, 0, 1);
@@ -438,6 +466,7 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 {
        struct net_bridge_port *p;
        int err = 0;
+       unsigned br_hr, dev_hr;
        bool changed_addr;
 
        /* Don't allow bridging non-ethernet like devices, or DSA-enabled
@@ -505,8 +534,12 @@ int br_add_if(struct net_bridge *br, struct net_device *dev)
 
        netdev_update_features(br->dev);
 
-       if (br->dev->needed_headroom < dev->needed_headroom)
-               br->dev->needed_headroom = dev->needed_headroom;
+       br_hr = br->dev->needed_headroom;
+       dev_hr = netdev_get_fwd_headroom(dev);
+       if (br_hr < dev_hr)
+               update_headroom(br, dev_hr);
+       else
+               netdev_set_rx_headroom(dev, br_hr);
 
        if (br_fdb_insert(br, p, dev->dev_addr, 0))
                netdev_err(dev, "failed insert local address bridge forwarding table\n");