bonding: implement bond_poll_controller()

This patches implements the poll_controller support for all
bonding driver. If the slaves have poll_controller net_op defined,
this implementation calls them. This is mode agnostic implementation
and iterates through all slaves (based on mode) and calls respective
handler.
Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -928,6 +928,39 @@ static inline void slave_disable_netpoll(struct slave *slave)
 
 static void bond_poll_controller(struct net_device *bond_dev)
 {
+	struct bonding *bond = netdev_priv(bond_dev);
+	struct slave *slave = NULL;
+	struct list_head *iter;
+	struct ad_info ad_info;
+	struct netpoll_info *ni;
+	const struct net_device_ops *ops;
+
+	if (BOND_MODE(bond) == BOND_MODE_8023AD)
+		if (bond_3ad_get_active_agg_info(bond, &ad_info))
+			return;
+
+	rcu_read_lock_bh();
+	bond_for_each_slave_rcu(bond, slave, iter) {
+		ops = slave->dev->netdev_ops;
+		if (!bond_slave_is_up(slave) || !ops->ndo_poll_controller)
+			continue;
+
+		if (BOND_MODE(bond) == BOND_MODE_8023AD) {
+			struct aggregator *agg =
+			    SLAVE_AD_INFO(slave)->port.aggregator;
+
+			if (agg &&
+			    agg->aggregator_identifier != ad_info.aggregator_id)
+				continue;
+		}
+
+		ni = rcu_dereference_bh(slave->dev->npinfo);
+		if (down_trylock(&ni->dev_lock))
+			continue;
+		ops->ndo_poll_controller(slave->dev);
+		up(&ni->dev_lock);
+	}
+	rcu_read_unlock_bh();
 }
 
 static void bond_netpoll_cleanup(struct net_device *bond_dev)