posix-cpu-timers: Use clock ID in posix_cpu_timer_get()

Extract the clock ID (PROF/VIRT/SCHED) from the clock selector and use it
as argument to the sample functions. That allows to simplify them once all
callers are fixed.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lkml.kernel.org/r/20190821192920.155487201@linutronix.de

kernel/time/posix-cpu-timers.c

@@ -699,6 +699,7 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
 
 static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
 {
+	clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
 	struct task_struct *p = timer->it.cpu.task;
 	u64 now;
 
@@ -717,7 +718,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp
 	 * Sample the clock to take the difference with the expiry time.
 	 */
 	if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
-		cpu_clock_sample(timer->it_clock, p, &now);
+		cpu_clock_sample(clkid, p, &now);
 	} else {
 		struct sighand_struct *sighand;
 		unsigned long flags;
@@ -737,7 +738,7 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp
 			timer->it.cpu.expires = 0;
 			return;
 		} else {
-			cpu_clock_sample_group(timer->it_clock, p, &now, false);
+			cpu_clock_sample_group(clkid, p, &now, false);
 			unlock_task_sighand(p, &flags);
 		}
 	}