On Fri, Jan 13, 2017 at 10:31:27PM +0200, Leon Romanovsky wrote: > > This is about what happens if the multicast MTU < unicast MTU - which > > is *exactly* the same case on RC and UD. > > > > IPoIB cannot send a 64k multicast MTU on RC either. > > Multicast is sent in datagram despite being in connected mode and for > datagram the MTU is limited by IB I am aware of that. Read you patch again: > + if (priv->mcast_mtu < priv->admin_mtu) > + ipoib_warn(priv, "MTU must be smaller than mcast_mtu (%u)\n", This check is fails in RC mode as well. And we already check if the requested MTU is beyond the port capability: + if (new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu)) + return -EINVAL; So I have *no idea* why you'd want to check it against the multicast group too.. It is OK for the multicast group to have a smaller MTU than the unicast side. This is how RC operates after all. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
