clocksource: add unregister function to disable unusable clocksources
On x86 the PIT might become an unusable clocksource. Add an unregister
function to provide a possibilty to remove the PIT from the list of
available clock sources.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index edd5ef8..6e9259a 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -337,6 +337,21 @@
spin_unlock_irqrestore(&clocksource_lock, flags);
}
+/**
+ * clocksource_unregister - remove a registered clocksource
+ */
+void clocksource_unregister(struct clocksource *cs)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocksource_lock, flags);
+ list_del(&cs->list);
+ if (clocksource_override == cs)
+ clocksource_override = NULL;
+ next_clocksource = select_clocksource();
+ spin_unlock_irqrestore(&clocksource_lock, flags);
+}
+
#ifdef CONFIG_SYSFS
/**
* sysfs_show_current_clocksources - sysfs interface for current clocksource
