[openib-general] Re: ipoib_mcast_send.patch

[Roland Dreier]

    Michael> Thats identical to what I posted till this point - right?

I think I added one blank line, but other than that, yes.

    Michael> I thought its important for performance to queue packets
    Michael> under mcast->pkt_queue? If not why do we do it?  Maybe we
    Michael> shouldnt call netif_carrier_on if we drop all packets?

The queueing is there so that we aren't guaranteed to drop the first
multicast packet sent to a given group.  I'm not sure that it really
is important, but it does seem like it would be bad to lose that
packet every time.

>From reading the code we can't call netif_carrier_on until after
priv->broadcast has the attached flag set.  In ipoib_mcast_join_task(),
we have

	if (!test_bit(IPOIB_MCAST_FLAG_ATTACHED, &priv->broadcast->flags)) {
		ipoib_mcast_join(dev, priv->broadcast, 0);
		return;
	}

and then at the very bottom

	netif_carrier_on(dev);

 - R.