Subject: Question on ipmr.c locking in 2.6.25

From: Ben Greear <[email-masked]>
Date: Wed, 28 May 2008 14:38:54 -0700

It looks like this method can return without unlocking the
mrt_lock or mfc_unres_lock.  Is this a bug, or am I just
confused about how it is supposed to work?

I haven't reproduced any problem..just staring at the code
while trying to add support for multiple routing tables...

static struct mfc_cache *ipmr_mfc_seq_idx(struct ipmr_mfc_iter *it, loff_t pos)
{
	struct mfc_cache *mfc;

	it->cache = mfc_cache_array;
	read_lock(&mrt_lock);
	for (it->ct = 0; it->ct < MFC_LINES; it->ct++)
		for (mfc = mfc_cache_array[it->ct]; mfc; mfc = mfc->next)
			if (pos-- == 0)
				return mfc;
	read_unlock(&mrt_lock);

	it->cache = &mfc_unres_queue;
	spin_lock_bh(&mfc_unres_lock);
	for (mfc = mfc_unres_queue; mfc; mfc = mfc->next)
		if (pos-- == 0)
			return mfc;
	spin_unlock_bh(&mfc_unres_lock);

	it->cache = NULL;
	return NULL;
}

Thanks,
Ben

-- 
Ben Greear <[email-masked]>
Candela Technologies Inc  http://www.candelatech.com