clockevents: Move C3 stop test outside lock

Avoid taking broadcast_lock in the idle path for systems where the
timer doesn't stop in C3.

[ tglx: Removed the stale label and added comment ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Dave Kleikamp <dkleikamp@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: lenb@kernel.org
Cc: paulmck@us.ibm.com
Link: http://lkml.kernel.org/r/%3C20110504234806.GF2925%40one.firstfloor.org%3E
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 9 insertions, 7 deletions

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index da800ffa810c..827e0f862da4 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -456,23 +456,27 @@ void tick_broadcast_oneshot_control(unsigned long reason)
         unsigned long flags;
         int cpu;
 
-        raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
-
         /*
          * Periodic mode does not care about the enter/exit of power
          * states
          */
         if (tick_broadcast_device.mode == TICKDEV_MODE_PERIODIC)
-                goto out;
+                return;
 
-        bc = tick_broadcast_device.evtdev;
+        /*
+         * We are called with preemtion disabled from the depth of the
+         * idle code, so we can't be moved away.
+         */
         cpu = smp_processor_id();
         td = &per_cpu(tick_cpu_device, cpu);
         dev = td->evtdev;
 
         if (!(dev->features & CLOCK_EVT_FEAT_C3STOP))
-                goto out;
+                return;
+
+        bc = tick_broadcast_device.evtdev;
 
+        raw_spin_lock_irqsave(&tick_broadcast_lock, flags);
         if (reason == CLOCK_EVT_NOTIFY_BROADCAST_ENTER) {
                 if (!cpumask_test_cpu(cpu, tick_get_broadcast_oneshot_mask())) {
                         cpumask_set_cpu(cpu, tick_get_broadcast_oneshot_mask());
@@ -489,8 +493,6 @@ void tick_broadcast_oneshot_control(unsigned long reason)
                                 tick_program_event(dev->next_event, 1);
                 }
         }
-
-out:
         raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags);
 }