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authorThomas Gleixner <tglx@linutronix.de>2013-04-25 20:31:44 +0000
committerThomas Gleixner <tglx@linutronix.de>2013-05-16 11:09:14 +0200
commitba919d1caa2e624eb8c6cae1f2ce0a253e697d45 (patch)
tree3f1ca3d84720e41093cd6723ff4a92122ecfec2e
parent5d33b883aed81c6fbcd09c6f7c3619eee850a7e2 (diff)
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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>
-rw-r--r--include/linux/clocksource.h2
-rw-r--r--kernel/time/clocksource.c6
-rw-r--r--kernel/time/timekeeping.c5
3 files changed, 7 insertions, 6 deletions
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 @@ static inline void __clocksource_updatefreq_khz(struct clocksource *cs, u32 khz)
}
-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 @@ static void clocksource_select(void)
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 @@ static int change_clocksource(void *data)
* 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;
}
/**
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