[openib-general] [PATCH 1/2] rdma_cm: add support to join IPOIB multicast groups

[Sean Hefty]

> The peer IPoIB would send an ARP and then would assume it can send its
> packets to the QP number provided in the arp reply, so it would be
> talking not with the rdma cm consumer but rather with the underlying
> IPoIB in this node.

Okay - so you want to change the QPN from that given in the ARP?  I missed that 
you wanted this, and I think I understand better what you're trying to do.

> no! it is broken since the PS_IPOIB ID/QP that joined/attached the
> multicast group is now using the ipoib broadcast qkey where the PS_UDP
> ID/QP is using the RDMA_UDP_QKEY

I'm only trying to support communication within the same port space, not between 
them.  Unicast is supported between different RDMA_PS_IPOIB QPs.  The question 
is how to obtain the IB unicast address (i.e. QPN, etc.) for RDMA_PS_IPOIB.  My 
assumption was that this capability wasn't needed, but you're saying that it is. 
  I will update the patches.

- Sean