[PATCH v2] hrtimer: Return ktime_t from hrtimer_get_next_event()/hrtimer_next_event_without()

[Thomas Weißschuh]

These functions really work in terms of ktime_t and not u64.

Change their return types and adapt the callers.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
---
Changes in v2:
- Rebase on v7.1-rc1
- Link to v1: https://patch.msgid.link/20260409-hrtimer-next_event-v1-1-df424f2c8621@xxxxxxxxxxxxx
---
 include/linux/hrtimer.h  | 4 ++--
 kernel/time/hrtimer.c    | 8 ++++----
 kernel/time/tick-sched.c | 3 +--
 kernel/time/timer.c      | 2 +-
 4 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 9ced498fefaa..1898706d0b87 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -254,8 +254,8 @@ static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer)
 	return __hrtimer_get_remaining(timer, false);
 }
 
-extern u64 hrtimer_get_next_event(void);
-extern u64 hrtimer_next_event_without(const struct hrtimer *exclude);
+extern ktime_t hrtimer_get_next_event(void);
+extern ktime_t hrtimer_next_event_without(const struct hrtimer *exclude);
 
 extern bool hrtimer_active(const struct hrtimer *timer);
 
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 5bd6efe598f0..2f41e55cc524 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1681,10 +1681,10 @@ EXPORT_SYMBOL_GPL(__hrtimer_get_remaining);
  *
  * Returns the next expiry time or KTIME_MAX if no timer is pending.
  */
-u64 hrtimer_get_next_event(void)
+ktime_t hrtimer_get_next_event(void)
 {
 	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
-	u64 expires = KTIME_MAX;
+	ktime_t expires = KTIME_MAX;
 
 	guard(raw_spinlock_irqsave)(&cpu_base->lock);
 	if (!hrtimer_hres_active(cpu_base))
@@ -1700,10 +1700,10 @@ u64 hrtimer_get_next_event(void)
  * Returns the next expiry time over all timers except for the @exclude one or
  * KTIME_MAX if none of them is pending.
  */
-u64 hrtimer_next_event_without(const struct hrtimer *exclude)
+ktime_t hrtimer_next_event_without(const struct hrtimer *exclude)
 {
 	struct hrtimer_cpu_base *cpu_base = this_cpu_ptr(&hrtimer_bases);
-	u64 expires = KTIME_MAX;
+	ktime_t expires = KTIME_MAX;
 	unsigned int active;
 
 	guard(raw_spinlock_irqsave)(&cpu_base->lock);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index cbbb87a0c6e7..3026a301dff7 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -1407,8 +1407,7 @@ ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next)
 	 * If the next highres timer to expire is earlier than 'next_event', the
 	 * idle governor needs to know that.
 	 */
-	next_event = min_t(u64, next_event,
-			   hrtimer_next_event_without(&ts->sched_timer));
+	next_event = min(next_event, hrtimer_next_event_without(&ts->sched_timer));
 
 	return ktime_sub(next_event, now);
 }
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 04d928c21aba..655a8c6cd84d 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1932,7 +1932,7 @@ static void timer_recalc_next_expiry(struct timer_base *base)
  */
 static u64 cmp_next_hrtimer_event(u64 basem, u64 expires)
 {
-	u64 nextevt = hrtimer_get_next_event();
+	u64 nextevt = ktime_to_ns(hrtimer_get_next_event());
 
 	/*
 	 * If high resolution timers are enabled

---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20260409-hrtimer-next_event-f6b7f1bf685f

Best regards,
--  
Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>