Fork safe clarification

[Matthew Small <matthewtsmall-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

I am trying to understand the behavior of the libibverbs after it has been
set into fork safe mode via a successful call to ibv_fork_init() or setting
the environmental variable IBV_FORK_SAFE.  For my purposes I would like to
know the following :

Are PDs, QPs and CQs created before a fork shared by the parent and child
after fork() has returned (ie. both can submit WRs, poll CQ, etc.)?


What about MRs registered before the fork?  Even though the child doesn't
have access to the parent's memory, can he sill submit WRs on a QP with an
MR created before the fork?


What if the MR pages in the above scenario are accessible in both parent and
child (shared memory)?  Are there complications with registering shared
memory?


In general, are pointers returned by libibverbs pointer to user/process
address space (as ibv_mr pointers must be) or kernel space (eg.  if an
unrelated process had another process's QP pointer, lkey, and a virtual
address could it post (almost certainly unsafely) a WR to the other
process's QP?


Sorry if the questions seem progressively more goofy and thanks in advance
for any clarification.

-Matt
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