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

[Sean Hefty]

> However, it will not support "mixed mode" communication patterns (which 
> you were raising last week) that is one app having a UD QP for both 
> multicast and unicast that talks with two "peers" IPoIB multicast and 
> another app doing only unicast.

Separating ipoib to its own port space alleviated my concerns on existing usage. 
  The RDMA_PS_UDP continues operating as before, with mixed mode traffic 
supported.  Mixed mode for RDMA_PS_IPOIB is not supported, since it's not clear 
to me how that would be used.  The IPOIB protocol doesn't use SIDR, so I'm 
hesitant to extend the capabilities until there's a clear need/use.

> Also, just a clarification - how exactly the patch enforces that an app 
> would not be able to do listen/connect/accept on RDMA_PS_IPOIB ID???

This is not enforce directly yet.  (It just requires an if statement in resolve 
route.)  I would expect that if it were tried, there would be a failure at some 
point.

- Sean