[asterisk-dev] Astobj2 and locks

[Watkins, Bradley]

I'm working on some pretty big changes to app_queue for internal use (if
I think it'll end up remotely useful to the community, I'll be certain
to submit a patch), and it looks like the features of astobj2 are
exactly what I need.

However, I'm trying to understand its use, and I've either found some
bugs in existing usage or I'm missing something (I don't rule out the
latter in any way).

When iterating through a container using ao2_iterator_next, it seems as
though you should need to wrap any changes to the returned object with
calls to ao2_lock() and subsequently ao2_unlock() after the changes are
complete.

But here is a snippet from app_queue.c in branches/1.4:

mem_iter = ao2_iterator_init(q->members, 0);
while ((m = ao2_iterator_next(&mem_iter))) {
	q->membercount++;
	if (m->realtime)
	m->dead = 1;
	ao2_ref(m, -1);
}


I would expect (based on my cursory glance at the implementation in
astobj2.c) that it should look something like:

mem_iter = ao2_iterator_init(q->members, 0);
while ((m = ao2_iterator_next(&mem_iter))) {
	q->membercount++;
	if (m->realtime) {
		if(ao2_lock(m)) {
			m->dead = 1;
			ao2_unlock(m);
		}
	}
	ao2_ref(m, -1);
}



Do I have it all wrong somehow?  And if so, please educate me as to how
so that I may be enlightened.

Regards,
- Brad