[PATCH tip/core/rcu 13/15] rcu: Make rcu_idle_enter() rely on callers disabling irqs

From	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Newsgroups	linux.kernel
Subject	[PATCH tip/core/rcu 13/15] rcu: Make rcu_idle_enter() rely on callers disabling irqs
Date	2017-07-24 23:50 +0200
Message-ID	<u6ToK-2fn-9@gated-at.bofh.it> (permalink)
References	<u6ToJ-2fn-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: "Peter Zijlstra (Intel)" <peterz@infradead.org>

All callers to rcu_idle_enter() have irqs disabled, so there is no
point in rcu_idle_enter disabling them again.  This commit therefore
replaces the irq disabling with a RCU_LOCKDEP_WARN().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/tree.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c028eb254704..64b2cb9a8830 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -843,11 +843,8 @@ static void rcu_eqs_enter(bool user)
  */
 void rcu_idle_enter(void)
 {
-	unsigned long flags;
-
-	local_irq_save(flags);
+	RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_idle_enter() invoked with irqs enabled!!!");
 	rcu_eqs_enter(false);
-	local_irq_restore(flags);
 }
 EXPORT_SYMBOL_GPL(rcu_idle_enter);
 
-- 
2.5.2

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[PATCH tip/core/rcu 13/15] rcu: Make rcu_idle_enter() rely on callers disabling irqs "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-07-24 23:50 +0200

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