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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>
hifive-unleashed-5.1
Thomas Gleixner 2013-04-25 20:31:44 +00:00
parent 5d33b883ae
commit ba919d1caa
3 changed files with 7 additions and 6 deletions
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2
include/linux/clocksource.h
View File

@ -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 *);

6
kernel/time/clocksource.c
View File

@ -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);
}
}

5
kernel/time/timekeeping.c
View File

@ -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;
}
/**