bonding: show saner speed for broadcast mode

Broadcast mode bonds transmit a copy of all traffic simultaneously out of
all interfaces, so the "speed" of the bond isn't really the aggregate of
all interfaces, but rather, the speed of the slowest active interface.

Also, the type of the speed field is u32, not unsigned long, so adjust
that accordingly, as required to make min() function here without
complaining about mismatching types.

Fixes: bb5b052f ("bond: add support to read speed and duplex via ethtool")
CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Veaceslav Falico <vfalico@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -4552,13 +4552,23 @@ static netdev_tx_t bond_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	return ret;
 }
 
+static u32 bond_mode_bcast_speed(struct slave *slave, u32 speed)
+{
+	if (speed == 0 || speed == SPEED_UNKNOWN)
+		speed = slave->speed;
+	else
+		speed = min(speed, slave->speed);
+
+	return speed;
+}
+
 static int bond_ethtool_get_link_ksettings(struct net_device *bond_dev,
 					   struct ethtool_link_ksettings *cmd)
 {
 	struct bonding *bond = netdev_priv(bond_dev);
-	unsigned long speed = 0;
 	struct list_head *iter;
 	struct slave *slave;
+	u32 speed = 0;
 
 	cmd->base.duplex = DUPLEX_UNKNOWN;
 	cmd->base.port = PORT_OTHER;
@@ -4570,8 +4580,13 @@ static int bond_ethtool_get_link_ksettings(struct net_device *bond_dev,
 	 */
 	bond_for_each_slave(bond, slave, iter) {
 		if (bond_slave_can_tx(slave)) {
-			if (slave->speed != SPEED_UNKNOWN)
+			if (slave->speed != SPEED_UNKNOWN) {
+				if (BOND_MODE(bond) == BOND_MODE_BROADCAST)
+					speed = bond_mode_bcast_speed(slave,
+								      speed);
+				else
 					speed += slave->speed;
+			}
 			if (cmd->base.duplex == DUPLEX_UNKNOWN &&
 			    slave->duplex != DUPLEX_UNKNOWN)
 				cmd->base.duplex = slave->duplex;