clocksource: Let timekeeping_notify return success/error
timekeeping_notify() can fail due cs->enable() failure. Though the
caller does not notice and happily keeps the wrong clocksource as the
current one.
Let the caller know about failure, so the current clocksource will be
shown correctly in sysfs.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130425143435.696321912@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 7279b94..aa6ba44 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -321,7 +321,7 @@
}
-extern void timekeeping_notify(struct clocksource *clock);
+extern int timekeeping_notify(struct clocksource *clock);
extern cycle_t clocksource_mmio_readl_up(struct clocksource *);
extern cycle_t clocksource_mmio_readl_down(struct clocksource *);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index dda5c71..1923a34 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -611,10 +611,10 @@
best = cs;
break;
}
- if (curr_clocksource != best) {
- printk(KERN_INFO "Switching to clocksource %s\n", best->name);
+
+ if (curr_clocksource != best && !timekeeping_notify(best)) {
+ pr_info("Switched to clocksource %s\n", best->name);
curr_clocksource = best;
- timekeeping_notify(curr_clocksource);
}
}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 98cd470..da6e10c 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -648,14 +648,15 @@
* This function is called from clocksource.c after a new, better clock
* source has been registered. The caller holds the clocksource_mutex.
*/
-void timekeeping_notify(struct clocksource *clock)
+int timekeeping_notify(struct clocksource *clock)
{
struct timekeeper *tk = &timekeeper;
if (tk->clock == clock)
- return;
+ return 0;
stop_machine(change_clocksource, clock, NULL);
tick_clock_notify();
+ return tk->clock == clock ? 0 : -1;
}
/**