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* [PATCH net-next-2.6] net: introduce rcu_dereference_read_lock_or_rtnl
@ 2010-09-07 20:11 Eric Dumazet
  2010-09-07 20:49 ` Jarek Poplawski
  0 siblings, 1 reply; 6+ messages in thread
From: Eric Dumazet @ 2010-09-07 20:11 UTC (permalink / raw)
  To: David Miller; +Cc: netdev

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 |   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);
 



^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2010-09-08 21:15 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2010-09-07 20:11 [PATCH net-next-2.6] net: introduce rcu_dereference_read_lock_or_rtnl Eric Dumazet
2010-09-07 20:49 ` Jarek Poplawski
2010-09-07 21:07   ` [PATCH net-next-2.6] net: introduce rcu_dereference_rtnl Eric Dumazet
2010-09-08 18:29     ` Ben Hutchings
2010-09-08 18:44       ` Eric Dumazet
2010-09-08 21:15         ` David Miller

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