From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Ingo Molnar <mingo@elte.hu>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH -tip] rcu: local_irq_disable() also delimits RCU_SCHED read-site critical sections
Date: Tue, 16 Mar 2010 19:09:21 +0800 [thread overview]
Message-ID: <4B9F66E1.2060309@cn.fujitsu.com> (raw)
It is documented that local_irq_disable() also delimits
RCU_SCHED read-site critical sections.
See the document of synchronize_sched() or
Documentation/RCU/whatisRCU.txt.
So we have to test irqs_disabled() in rcu_read_lock_sched_held().
Otherwise rcu-lockdep brings incorrect complaint.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 3024050..2ce5674 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -160,7 +160,7 @@ static inline int rcu_read_lock_sched_held(void)
return 1;
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
- return lockdep_opinion || preempt_count() != 0;
+ return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
}
#else /* #ifdef CONFIG_PREEMPT */
static inline int rcu_read_lock_sched_held(void)
@@ -191,7 +191,7 @@ static inline int rcu_read_lock_bh_held(void)
#ifdef CONFIG_PREEMPT
static inline int rcu_read_lock_sched_held(void)
{
- return !rcu_scheduler_active || preempt_count() != 0;
+ return !rcu_scheduler_active || preempt_count() != 0 || irqs_disabled();
}
#else /* #ifdef CONFIG_PREEMPT */
static inline int rcu_read_lock_sched_held(void)
next reply other threads:[~2010-03-16 11:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-16 11:09 Lai Jiangshan [this message]
2010-03-16 11:28 ` [PATCH -tip] rcu: local_irq_disable() also delimits RCU_SCHED read-site critical sections Ingo Molnar
2010-03-16 13:21 ` Paul E. McKenney
2010-03-17 1:41 ` Lai Jiangshan
2010-03-17 2:26 ` Paul E. McKenney
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