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authorThomas Gleixner <tglx@linutronix.de>2013-04-25 20:31:46 +0000
committerThomas Gleixner <tglx@linutronix.de>2013-05-16 11:09:16 +0200
commita89c7edbe7d7aa80f507915f3dd801211b116b79 (patch)
tree9981bee7be59b28979438fc2701228874856607b /kernel/time
parent7eaeb34305dee26634f7c98ae62646da5cebe91d (diff)
downloadop-kernel-dev-a89c7edbe7d7aa80f507915f3dd801211b116b79.zip
op-kernel-dev-a89c7edbe7d7aa80f507915f3dd801211b116b79.tar.gz
clocksource: Let clocksource_unregister() return success/error
The unregister call can fail, if the clocksource is the current one and there is no replacement clocksource available. It can also fail, if the clocksource is the watchdog clocksource and I'm not going to provide support for this. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Magnus Damm <magnus.damm@gmail.com> Link: http://lkml.kernel.org/r/20130425143436.029915527@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/clocksource.c33
1 files changed, 12 insertions, 21 deletions
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 791d1ae..31b9033 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -389,28 +389,17 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
static void clocksource_dequeue_watchdog(struct clocksource *cs)
{
- struct clocksource *tmp;
unsigned long flags;
spin_lock_irqsave(&watchdog_lock, flags);
- if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
- /* cs is a watched clocksource. */
- list_del_init(&cs->wd_list);
- } else if (cs == watchdog) {
- /* Reset watchdog cycles */
- clocksource_reset_watchdog();
- /* Current watchdog is removed. Find an alternative. */
- watchdog = NULL;
- list_for_each_entry(tmp, &clocksource_list, list) {
- if (tmp == cs || tmp->flags & CLOCK_SOURCE_MUST_VERIFY)
- continue;
- if (!watchdog || tmp->rating > watchdog->rating)
- watchdog = tmp;
+ if (cs != watchdog) {
+ if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
+ /* cs is a watched clocksource. */
+ list_del_init(&cs->wd_list);
+ /* Check if the watchdog timer needs to be stopped. */
+ clocksource_stop_watchdog();
}
}
- cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
- /* Check if the watchdog timer needs to be stopped. */
- clocksource_stop_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
}
@@ -841,13 +830,15 @@ static int clocksource_unbind(struct clocksource *cs)
* clocksource_unregister - remove a registered clocksource
* @cs: clocksource to be unregistered
*/
-void clocksource_unregister(struct clocksource *cs)
+int clocksource_unregister(struct clocksource *cs)
{
+ int ret = 0;
+
mutex_lock(&clocksource_mutex);
- clocksource_dequeue_watchdog(cs);
- list_del(&cs->list);
- clocksource_select();
+ if (!list_empty(&cs->list))
+ ret = clocksource_unbind(cs);
mutex_unlock(&clocksource_mutex);
+ return ret;
}
EXPORT_SYMBOL(clocksource_unregister);
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