From: Johannes Berg <johannes@sipsolutions.net>
Date: Sat, 29 Mar 2008 01:54:09 +0100

Maybe we should check which schedule_work users actually lock the rtnl
within the work function and move them to a uses-rtnl-in-work workqueue
so that everybody else can have rtnl around flush.

The issue is that linkwatch goes: workqueue lock --> RTNL

And thus taking workqueue lock within RTNL is deadlock
prone no matter where you do it.