netdev - Re: [PATCH] rebalance locks by converting write_lock_bh to write_lock+local_bh

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Message-Id: <20131123.143929.975712910203893827.davem@davemloft.net>
Date:	Sat, 23 Nov 2013 14:39:29 -0800 (PST)
From:	David Miller <davem@...emloft.net>
To:	der.herr@...r.at
Cc:	kuznet@....inr.ac.ru, eric.dumazet@...il.com, roque@...fc.ul.pt,
	peterz@...radead.org, netdev@...r.kernel.org
Subject: Re: [PATCH] rebalance locks by converting write_lock_bh to
 write_lock+local_bh_disable

From: Nicholas Mc Guire <der.herr@...r.at>
Date: Fri, 22 Nov 2013 00:54:02 +0100

> From 2c8e669b691b825c0ed2a02bd7a698d8ed5c6d29 Mon Sep 17 00:00:00 2001
> From: Nicholas Mc Guire <der.herr@...r.at>
> Date: Thu, 21 Nov 2013 18:22:55 -0500
> Subject: [PATCH] rebalance locks by converting write_lock_bh to write_lock+local_bh_disable
>  
> 
>  in __neigh_event_send write_lock_bh(&neigh->lock) is implicitly balanced by
>  write_unlock(&neigh->lock)+local_bh_disable() - while this is equivalent with
>  respect to the effective low level locking primitives it breaks balancing
>  in the locking api. This makes automatic lock-checking trigger false 
>  positives, creates an implicit dependency between *_lock_bh and *_lock 
>  functions as well as making the extremly simply locking of net core even
>  easier to understand.
> 
>  The api inbalance was introduced in:
>  commit cd28ca0a3dd17c68d24b839602a0e6268ad28b5d
>  Author: Eric Dumazet <eric.dumazet@...il.com>
>  This patch just rebalances the lock api
> 
>  No change of functionality
> 
> Signed-off-by: Nicholas Mc Guire <der.herr@...r.at>

This is a valid locking idiom, fix the lock checking.
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