bonding: get netdev_rx_handler_unregister out of locks

commit fcd99434 upstream.

Now that netdev_rx_handler_unregister contains synchronize_net(), we need
to call it outside of bond->lock, cause it might sleep. Also, remove the
already unneded synchronize_net().
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/net/bonding/bond_main.c

@@ -1934,12 +1934,11 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 		return -EINVAL;
 	}
 
+	write_unlock_bh(&bond->lock);
 	/* unregister rx_handler early so bond_handle_frame wouldn't be called
 	 * for this slave anymore.
 	 */
 	netdev_rx_handler_unregister(slave_dev);
-	write_unlock_bh(&bond->lock);
-	synchronize_net();
 	write_lock_bh(&bond->lock);
 
 	if (!bond->params.fail_over_mac) {