From 4713e22ce81eb8b3353e16435362eb3d0ec95640 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 30 Jan 2008 13:30:02 +0100 Subject: [PATCH] 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 Signed-off-by: Ingo Molnar --- arch/x86/kernel/i8253.c | 1 + include/linux/clocksource.h | 1 + kernel/time/clocksource.c | 15 +++++++++++++++ 3 files changed, 17 insertions(+) diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index 0f8f35458a8..decc5d294d7 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -13,6 +13,7 @@ #include #include #include +#include DEFINE_SPINLOCK(i8253_lock); EXPORT_SYMBOL(i8253_lock); diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 07b42153de2..85778a4b120 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -215,6 +215,7 @@ static inline void clocksource_calculate_interval(struct clocksource *c, /* used to install a new clocksource */ extern int clocksource_register(struct clocksource*); +extern void clocksource_unregister(struct clocksource*); extern struct clocksource* clocksource_get_next(void); extern void clocksource_change_rating(struct clocksource *cs, int rating); extern void clocksource_resume(void); diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index edd5ef8e176..6e9259a5d50 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -337,6 +337,21 @@ void clocksource_change_rating(struct clocksource *cs, int rating) 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 -- 2.20.1