tick/sched: Cleanup confusing variables

tick_nohz_stop_tick() contains the expires (u64 variable) and tick
(ktime_t) variable. In the beginning the value of expires is written to
tick. Afterwards none of the variables is changed. They are only used for
checks.

Drop the not required variable tick and use always expires instead.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20231201092654.34614-3-anna-maria@linutronix.de

Author: anna-marialx

kernel/time/tick-sched.c

@@ -887,7 +887,6 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
 	struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
 	u64 basemono = ts->timer_expires_base;
 	u64 expires = ts->timer_expires;
-	ktime_t tick = expires;
 
 	/* Make sure we won't be trying to stop it twice in a row. */
 	ts->timer_expires_base = 0;
@@ -910,7 +909,7 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
 	/* Skip reprogram of event if it's not changed */
 	if (ts->tick_stopped && (expires == ts->next_tick)) {
 		/* Sanity check: make sure clockevent is actually programmed */
-		if (tick == KTIME_MAX || ts->next_tick == hrtimer_get_expires(&ts->sched_timer))
+		if (expires == KTIME_MAX || ts->next_tick == hrtimer_get_expires(&ts->sched_timer))
 			return;
 
 		WARN_ON_ONCE(1);
@@ -935,7 +934,7 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
 		trace_tick_stop(1, TICK_DEP_MASK_NONE);
 	}
 
-	ts->next_tick = tick;
+	ts->next_tick = expires;
 
 	/*
 	 * If the expiration time == KTIME_MAX, then we simply stop
@@ -950,11 +949,11 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, int cpu)
 	}
 
 	if (ts->nohz_mode == NOHZ_MODE_HIGHRES) {
-		hrtimer_start(&ts->sched_timer, tick,
+		hrtimer_start(&ts->sched_timer, expires,
 			      HRTIMER_MODE_ABS_PINNED_HARD);
 	} else {
-		hrtimer_set_expires(&ts->sched_timer, tick);
-		tick_program_event(tick, 1);
+		hrtimer_set_expires(&ts->sched_timer, expires);
+		tick_program_event(expires, 1);
 	}
 }