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

[Roland Dreier]

 > 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.

 > A module param enables adding a
 > 
 > options ib_ipoib umcast_allowed=1
 > 
 > line to /etc/modprobe.conf to make this setting persistent across
 > module unload/load (eg reboots) and be applied to all the devices
 > created by ipoib. A sysfs entry has to be explicitly written following
 > each device creation.

The umcast setting could be made persistent with a script that runs at
ipoib interface hotplug too.  In fact surely OFED must have this
infrastructure for setting connected mode, mtu, etc.

I really want to push back as much as possible on creating new module
parameters since we have too many as it is.

 - R.