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Subject[PATCH] tick: add check for the existence of broadcast clock event device
From 2f076e1867c8bbb145b74d289358174644d9fed8 Mon Sep 17 00:00:00 2001
From: Feng Tang <feng.tang@intel.com>
Date: Fri, 5 Jun 2009 10:36:15 +0800
Subject: [PATCH] tick: add check for the existence of broadcast clock event device

Some platform may have no broadcast clock event device, as it use always-on
external timers for per-cpu timer and has no extra one for broadcast device.
This check will secure the access to bc device when system get some boradcast
on/off and enter/exit message

Signed-off-by: Feng Tang <feng.tang@intel.com>
---
kernel/time/tick-broadcast.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 118a3b3..110e0bc 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -214,10 +214,13 @@ static void tick_do_broadcast_on_off(void *why)

spin_lock_irqsave(&tick_broadcast_lock, flags);

+ bc = tick_broadcast_device.evtdev;
+ if (!bc)
+ goto out;
+
cpu = smp_processor_id();
td = &per_cpu(tick_cpu_device, cpu);
dev = td->evtdev;
- bc = tick_broadcast_device.evtdev;

/*
* Is the device not affected by the powerstate ?
@@ -468,6 +471,9 @@ void tick_broadcast_oneshot_control(unsigned long reason)
goto out;

bc = tick_broadcast_device.evtdev;
+ if (!bc)
+ goto out;
+
cpu = smp_processor_id();
td = &per_cpu(tick_cpu_device, cpu);
dev = td->evtdev;
--
1.5.6.3

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