Patchwork [net-next-2.6] net: introduce rcu_dereference_rtnl

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Submitter Eric Dumazet
Date Sept. 8, 2010, 6:44 p.m.
Message ID <1283971469.2428.9.camel@edumazet-laptop>
Download mbox | patch
Permalink /patch/64194/
State Accepted
Delegated to: David Miller
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Comments

Eric Dumazet - Sept. 8, 2010, 6:44 p.m.
Le mercredi 08 septembre 2010 à 19:29 +0100, Ben Hutchings a écrit :

> No semicolon on the end, please.  The 'caller' will add that.

Oh definitely, thanks !

[PATCH net-next-2.6] net: introduce rcu_dereference_rtnl

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 <eric.dumazet@gmail.com>
---
 include/linux/rtnetlink.h |   11 +++++++++++
 1 file changed, 11 insertions(+)



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David Miller - Sept. 8, 2010, 9:15 p.m.
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Wed, 08 Sep 2010 20:44:29 +0200

> Le mercredi 08 septembre 2010 à 19:29 +0100, Ben Hutchings a écrit :
> 
>> No semicolon on the end, please.  The 'caller' will add that.
> 
> Oh definitely, thanks !
> 
> [PATCH net-next-2.6] net: introduce rcu_dereference_rtnl
> 
> 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 <eric.dumazet@gmail.com>

Applied, thanks Eric.
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Patch

diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 58d4449..263690d 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -749,6 +749,17 @@  extern int rtnl_is_locked(void);
 extern int lockdep_rtnl_is_held(void);
 #endif /* #ifdef CONFIG_PROVE_LOCKING */
 
+/**
+ * rcu_dereference_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_rtnl(p)					\
+	rcu_dereference_check(p, rcu_read_lock_held() ||	\
+				 lockdep_rtnl_is_held())
+
 extern void rtnetlink_init(void);
 extern void __rtnl_unlock(void);