bonding: Implement ndo_get_xmit_slave

Add implementation of ndo_get_xmit_slave. Find the slave by using the
helper function according to the bond mode. If the caller set all_slaves
to true, then it assumes that all slaves are available to transmit.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/bonding/bond_main.c

@@ -4347,6 +4347,48 @@ static u16 bond_select_queue(struct net_device *dev, struct sk_buff *skb,
 	return txq;
 }
 
+static struct net_device *bond_xmit_get_slave(struct net_device *master_dev,
+					      struct sk_buff *skb,
+					      bool all_slaves)
+{
+	struct bonding *bond = netdev_priv(master_dev);
+	struct bond_up_slave *slaves;
+	struct slave *slave = NULL;
+
+	switch (BOND_MODE(bond)) {
+	case BOND_MODE_ROUNDROBIN:
+		slave = bond_xmit_roundrobin_slave_get(bond, skb);
+		break;
+	case BOND_MODE_ACTIVEBACKUP:
+		slave = bond_xmit_activebackup_slave_get(bond, skb);
+		break;
+	case BOND_MODE_8023AD:
+	case BOND_MODE_XOR:
+		if (all_slaves)
+			slaves = rcu_dereference(bond->all_slaves);
+		else
+			slaves = rcu_dereference(bond->usable_slaves);
+		slave = bond_xmit_3ad_xor_slave_get(bond, skb, slaves);
+		break;
+	case BOND_MODE_BROADCAST:
+		break;
+	case BOND_MODE_ALB:
+		slave = bond_xmit_alb_slave_get(bond, skb);
+		break;
+	case BOND_MODE_TLB:
+		slave = bond_xmit_tlb_slave_get(bond, skb);
+		break;
+	default:
+		/* Should never happen, mode already checked */
+		WARN_ONCE(true, "Unknown bonding mode");
+		break;
+	}
+
+	if (slave)
+		return slave->dev;
+	return NULL;
+}
+
 static netdev_tx_t __bond_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct bonding *bond = netdev_priv(dev);
@@ -4468,6 +4510,7 @@ static const struct net_device_ops bond_netdev_ops = {
 	.ndo_del_slave		= bond_release,
 	.ndo_fix_features	= bond_fix_features,
 	.ndo_features_check	= passthru_features_check,
+	.ndo_get_xmit_slave	= bond_xmit_get_slave,
 };
 
 static const struct device_type bond_type = {