posix-timers: Handle relative timers with CONFIG_TIME_LOW_RES proper

As Helge reported for timerfd we have the same issue in posix timers. We
return remaining time larger than the programmed relative time to user space
in case of CONFIG_TIME_LOW_RES=y. Use the proper function to adjust the extra
time added in hrtimer_start_range_ns().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Helge Deller <deller@gmx.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20160114164159.450510905@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 31d11ac..f2826c3 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -760,7 +760,7 @@ common_timer_get(struct k_itimer *timr, struct itimerspec *cur_setting)
            (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE))
                timr->it_overrun += (unsigned int) hrtimer_forward(timer, now, iv);
 
-       remaining = ktime_sub(hrtimer_get_expires(timer), now);
+       remaining = __hrtimer_expires_remaining_adjusted(timer, now);
        /* Return 0 only, when the timer is expired and not pending */
        if (remaining.tv64 <= 0) {
                /*