[openib-general] [RFC] [PATCH 2/7] ib_multicast 2.6.20: add ib_multicast module to track join requests from the same port

[Michael S. Tsirkin]

Quoting r. Or Gerlitz <ogerlitz at voltaire.com>:
> The ipoib change is a must to allow for user space consumers to 
> join/leave groups whose MGID is "of IP multicast origin".
>
> So one process can have its IP mulitcast traffic carried out by ipoib 
> and another process can use librdmacm to join the same multicast group 
> and attach a QP to the same MGID.

Why is this even a good idea?
If you are looking for reasons using mutlicast module in ipoib is good, I would
say blocking unpriviledged userspace from joining IPoIB GID and snoopig on all
mcast traffic sounds like a better idea.  BTW, Sean, I think this is something
we need for the ucma multicast part to go in. I would imagine kernel components
could set some kind of flag on mcast join to make them exclusive.
API currently does not allow for that.

And why the rush? Is the new module used at all yet?
Let's see it get some use before switching a basic component over.

Finally, the patch in question also seems to introduce more cleanups and
such. It would be less controversial if it was just an API change.

-- 
MST