From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 27 Sep 2012 11:11:46 +0200
Subject: mm: page_alloc: Use local_lock_on() instead of plain spinlock
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git
Git-commit: 013d83037c6589d58a23ec9e16a4736c3b478e5c
Patch-mainline: Queued in subsystem maintainer repository
References: SLE Realtime Extension

The plain spinlock while sufficient does not update the local_lock
internals. Use a proper local_lock function instead to ease debugging.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Mike Galbraith <mgalbraith@suse.de>
---
 mm/page_alloc.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -293,9 +293,9 @@ static DEFINE_LOCAL_IRQ_LOCK(pa_lock);
 
 #ifdef CONFIG_PREEMPT_RT_BASE
 # define cpu_lock_irqsave(cpu, flags)		\
-	spin_lock_irqsave(&per_cpu(pa_lock, cpu).lock, flags)
+	local_lock_irqsave_on(pa_lock, flags, cpu)
 # define cpu_unlock_irqrestore(cpu, flags)	\
-	spin_unlock_irqrestore(&per_cpu(pa_lock, cpu).lock, flags)
+	local_unlock_irqrestore_on(pa_lock, flags, cpu)
 #else
 # define cpu_lock_irqsave(cpu, flags)		local_irq_save(flags)
 # define cpu_unlock_irqrestore(cpu, flags)	local_irq_restore(flags)