From: chas williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Date: Tue, 12 Aug 2014 08:12:26 -0400

> One should not call blocking primitives inside a wait loop, since both
> require task_struct::state to sleep, so the inner will destroy the
> outer state.
> 
> sigd_enq() will possibly sleep for alloc_skb().  Move sigd_enq() before
> prepare_to_wait() to avoid sleeping while waiting interruptibly.  You do
> not actually need to call sigd_enq() after the initial prepare_to_wait()
> because we test the termination condition before calling schedule().
> 
> Based on suggestions from Peter Zijlstra.
> 
> Signed-off-by: Chas Williams <chas@cmf.n4rl.navy.mil>
> Acked-by: Peter Zijlstra <peterz@infradead.org>

Applied.