hrtimer: Factor out __hrtimer_next_event_base()

Preparatory patch for softirq based hrtimers to avoid code duplication.

No functional change.

Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Link: http://lkml.kernel.org/r/20171221104205.7269-25-anna-maria@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/time/hrtimer.c

@@ -458,13 +458,13 @@ __next_base(struct hrtimer_cpu_base *cpu_base, unsigned int *active)
 #define for_each_active_base(base, cpu_base, active)	\
 	while ((base = __next_base((cpu_base), &(active))))
 
-static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
+static ktime_t __hrtimer_next_event_base(struct hrtimer_cpu_base *cpu_base,
+					 unsigned int active,
+					 ktime_t expires_next)
 {
 	struct hrtimer_clock_base *base;
-	unsigned int active = cpu_base->active_bases;
-	ktime_t expires, expires_next = KTIME_MAX;
+	ktime_t expires;
 
-	cpu_base->next_timer = NULL;
 	for_each_active_base(base, cpu_base, active) {
 		struct timerqueue_node *next;
 		struct hrtimer *timer;
@@ -487,6 +487,18 @@ static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
 	return expires_next;
 }
 
+static ktime_t __hrtimer_get_next_event(struct hrtimer_cpu_base *cpu_base)
+{
+	unsigned int active = cpu_base->active_bases;
+	ktime_t expires_next = KTIME_MAX;
+
+	cpu_base->next_timer = NULL;
+
+	expires_next = __hrtimer_next_event_base(cpu_base, active, expires_next);
+
+	return expires_next;
+}
+
 static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base)
 {
 	ktime_t *offs_real = &base->clock_base[HRTIMER_BASE_REALTIME].offset;