bonding: use netdev_upper list in bond_vlan_used

Convert bond_vlan_used() to traverse the upper device list to see if we
have any vlans above us. It's protected by rcu, and in case we are holding
rtnl_lock we should call vlan_uses_dev() instead - it's faster.

CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 4bf52d5f637e..230197d7abc7 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -267,9 +267,22 @@ struct bonding {
 #endif /* CONFIG_DEBUG_FS */
 };
 
+/* if we hold rtnl_lock() - call vlan_uses_dev() */
 static inline bool bond_vlan_used(struct bonding *bond)
 {
-        return !list_empty(&bond->vlan_list);
+        struct net_device *upper;
+        struct list_head *iter;
+
+        rcu_read_lock();
+        netdev_for_each_upper_dev_rcu(bond->dev, upper, iter) {
+                if (upper->priv_flags & IFF_802_1Q_VLAN) {
+                        rcu_read_unlock();
+                        return true;
+                }
+        }
+        rcu_read_unlock();
+
+        return false;
 }
 
 #define bond_slave_get_rcu(dev) \