[ofa-general] librdmacm feature request

[Roland Dreier]

 > It shouldn't be too hard.  Assuming you handle the modify channel as a
 > synchronous action, the thread calling modify channel can't also be in
 > rdma_get_cm_event at the same time.  So, if you get there and someone is
 > blocking on that channel and just hasn't been scheduled to run yet, then
 > leave the event where it is while you switch the channel and send new
 > events to the new channel.  If they aren't then move any pending events
 > to the new channel as you do the change.

Hmm, how do you move events?  Keep in mind that there may be an
arbitrary number of pending events that belong to other cm_ids that
are queued before the events you want to move.  And you can't really
do anything too funky with the event channel fd, because you don't
want to mess up some other thread that might be waiting for events in
poll() or whatever.

 - R.