From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 21 Aug 2008 22:22:45 +1000

On Thu, Aug 21, 2008 at 12:19:20PM +0000, Jarek Poplawski wrote:

quoted

Since qdisc_destroy() is used for destroying root qdisc too, isn't it
better to get this lock back in notify_and_destroy() like this:

if (old) {
	if (parent)
		sch_tree_lock()
	qdisc_destroy()
	if (parent)
		sch_tree_unlock()
}

Ugly as it may look, I think this is probably the best fix for now.

For 2.6.28 we can fix it properly and remove this eyesore :)

This looks even worse, actually.

If we just unlinked this thing, we don't want anyone finding
it, even before we grab this lock, to adjust queue counts.