posix-timers: Convert timer_settime() to clockid_to_kclock()

Set the common function for CLOCK_MONOTONIC and CLOCK_REALTIME kclocks
and use the new decoding function.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Tested-by: Richard Cochran <richard.cochran@omicron.at>
LKML-Reference: <20110201134419.001863714@linutronix.de>

kernel/posix-timers.c

@@ -252,6 +252,7 @@ static __init int init_posix_timers(void)
 		.nsleep		= common_nsleep,
 		.nsleep_restart	= hrtimer_nanosleep_restart,
 		.timer_create	= common_timer_create,
+		.timer_set	= common_timer_set,
 	};
 	struct k_clock clock_monotonic = {
 		.clock_getres	= hrtimer_get_res,
@@ -259,6 +260,7 @@ static __init int init_posix_timers(void)
 		.nsleep		= common_nsleep,
 		.nsleep_restart	= hrtimer_nanosleep_restart,
 		.timer_create	= common_timer_create,
+		.timer_set	= common_timer_set,
 	};
 	struct k_clock clock_monotonic_raw = {
 		.clock_getres	= hrtimer_get_res,
@@ -814,6 +816,7 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
 	int error = 0;
 	unsigned long flag;
 	struct itimerspec *rtn = old_setting ? &old_spec : NULL;
+	struct k_clock *kc;
 
 	if (!new_setting)
 		return -EINVAL;
@@ -829,8 +832,11 @@ SYSCALL_DEFINE4(timer_settime, timer_t, timer_id, int, flags,
 	if (!timr)
 		return -EINVAL;
 
-	error = CLOCK_DISPATCH(timr->it_clock, timer_set,
-			       (timr, flags, &new_spec, rtn));
+	kc = clockid_to_kclock(timr->it_clock);
+	if (WARN_ON_ONCE(!kc || !kc->timer_set))
+		error = -EINVAL;
+	else
+		error = kc->timer_set(timr, flags, &new_spec, rtn);
 
 	unlock_timer(timr, flag);
 	if (error == TIMER_RETRY) {