From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next-2.6] net: introduce rcu_dereference_read_lock_or_rtnl Date: Tue, 07 Sep 2010 22:11:31 +0200 Message-ID: <1283890291.2634.143.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev To: David Miller Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:48313 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758232Ab0IGULg (ORCPT ); Tue, 7 Sep 2010 16:11:36 -0400 Received: by fxm16 with SMTP id 16so275383fxm.19 for ; Tue, 07 Sep 2010 13:11:35 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: We use rcu_dereference_check(p, rcu_read_lock_held() || lockdep_rtnl_is_held()) several times in network stack. More usages to come too, so its time to create a helper. Signed-off-by: Eric Dumazet --- include/linux/rtnetlink.h | 12 ++++++++++++ diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 58d4449..5ba48bb 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -745,10 +745,22 @@ extern void rtnl_lock(void); extern void rtnl_unlock(void); extern int rtnl_trylock(void); extern int rtnl_is_locked(void); + #ifdef CONFIG_PROVE_LOCKING extern int lockdep_rtnl_is_held(void); #endif /* #ifdef CONFIG_PROVE_LOCKING */ +/** + * rcu_dereference_read_lock_or_rtnl - rcu_dereference with debug checking + * @p: The pointer to read, prior to dereferencing + * + * Do an rcu_dereference(p), but check caller either holds rcu_read_lock() + * or RTNL + */ +#define rcu_dereference_read_lock_or_rtnl(p) \ + rcu_dereference_check(p, rcu_read_lock_held() || \ + lockdep_rtnl_is_held()); + extern void rtnetlink_init(void); extern void __rtnl_unlock(void);