[ofa-general] Re: [PATCH RFC v2] IB/ipoib: enable IGMP for userpsace multicast IB apps

[Or Gerlitz]

Roland Dreier wrote:
>  > So indeed the assumption in the patch is that mgids which translate to
>  > legal IP multicast addresses are inserted into the database either by
>  > ipoib or rdma-cm consumers who use IPOIB_PS for their ID's.
> 
> I guess since it's confiruable, it's OK.  But I think that you miss
> the fact that there might be other consumers of ib_sa creating
> multicast groups, and there might be other rdma_cm consumers using
> IPOIB_PS also.

I understand that there may be other ib_sa consumers that use multicast 
and other rdma_cm consumers that use IPOIB_PS, however, the point I was 
trying to make is that if there are consumers that join the --same-- 
multicast groups as ipoib they can actually avoid ipoib to join these 
group if they provide different attributes for the group.

This is why Sean made the rdma_cm to use the --same-- attributes as 
ipoib does for IPOIB_PS joins. For other joins the rdma-cm makes sure 
that the MGID is different (rdma-cm signature instead of the ipv4/v6 
one) and uses a different qkey.

Anyway, I understand that we are more or less on the same page regarding 
this point, correct?

Or.