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

[Sean Hefty]

Sean Hefty wrote:
>>>+				       int (*callback)(int status,
>>>+						       struct ib_multicast
>>>+							      *multicast),
>>>+				       void *context);
>>>+
>>
>>Is this re-introducing module unload races we had with sa all over again?
> 
> 
> The call returns a structure that must be freed.  If the structure is freed by
> returning a non-zero call to the callback, then we have the same problem that
> ib_cm and rdma_cm have.  Not allowing a return value from the callback is an
> easy fix for that though.

I looked at this in more detail.  While it's easy on the ib_multicast module to 
not allow returning a value from the callback, it makes it more difficult on the 
users to handle failures.  (The ipoib changes use this feature.)  So, I think we 
want registration with the ib_multicast module similar to what was done with the 
ib_sa.

- Sean