[NET]: Fix possible dev_deactivate race condition

[David Miller]

From: Herbert Xu <herbert at gondor.apana.org.au>
Date: Fri, 19 Oct 2007 13:36:24 +0800

> [NET]: Fix possible dev_deactivate race condition
> 
> The function dev_deactivate is supposed to only return when
> all outstanding transmissions have completed.  Unfortunately
> it is possible for store operations in the driver's transmit
> function to only become visible after dev_deactivate returns.
> 
> This patch fixes this by taking the queue lock after we see
> the end of the queue run.  This ensures that all effects of
> any previous transmit calls are visible.
> 
> If however we detect that there is another queue run occuring,
> then we'll warn about it because this should never happen as
> we have pointed dev->qdisc to noop_qdisc within the same queue
> lock earlier in the functino.
> 
> Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>

Applied, thanks Herbert!