[PATCH v2 0/9] hrtimer: Remove hrtimer_clock_base::get_time

[PATCH v2 0/9] hrtimer: Remove hrtimer_clock_base::get_time

[Thomas Weißschuh]

The get_time() callbacks always need to match the bases clockid.
Instead of maintaining that association twice in hrtimer_bases,
use a helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
---
Changes in v2:
- Pick up tags from the mailing list
- Reorder switch-case branches to match hrtimer_bases table
- Link to v1: https://lore.kernel.org/r/20250812-hrtimer-cleanup-get_time-v1-0-b962cd9d9385@linutronix.de

---
Thomas Weißschuh (9):
      posix-timers: Avoid direct access to hrtimer clockbase
      timers/itimer: Avoid direct access to hrtimer clockbase
      sched/core: Avoid direct access to hrtimer clockbase
      lib: test_objpool: Avoid direct access to hrtimer clockbase
      ALSA: hrtimer: Avoid direct access to hrtimer clockbase
      media: pwm-ir-tx: Avoid direct access to hrtimer clockbase
      hrtimer: Use hrtimer_cb_get_time() helper
      hrtimer: Remove hrtimer_clock_base::get_time
      hrtimer: Reorder branches in hrtimer_clockid_to_base()

 drivers/media/rc/pwm-ir-tx.c   |  5 +----
 include/linux/hrtimer.h        | 14 +++++---------
 include/linux/hrtimer_defs.h   |  2 --
 kernel/sched/core.c            |  2 +-
 kernel/time/hrtimer.c          | 38 +++++++++++++++++++++++++++-----------
 kernel/time/itimer.c           |  3 +--
 kernel/time/posix-timers.c     |  5 ++---
 kernel/time/timer_list.c       |  2 --
 lib/test_objpool.c             |  2 +-
 scripts/gdb/linux/timerlist.py |  2 --
 sound/core/hrtimer.c           |  2 +-
 11 files changed, 39 insertions(+), 38 deletions(-)
---
base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585
change-id: 20250728-hrtimer-cleanup-get_time-8ac9d797a685

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

[PATCH v2 1/9] posix-timers: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helpers.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/time/posix-timers.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 8b582174b1f9498a548fc1c214185577f994a647..2741f3725de48ea8f73cc279287631f9d5a6e960 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -299,8 +299,7 @@ static void common_hrtimer_rearm(struct k_itimer *timr)
 {
 	struct hrtimer *timer = &timr->it.real.timer;
 
-	timr->it_overrun += hrtimer_forward(timer, timer->base->get_time(),
-					    timr->it_interval);
+	timr->it_overrun += hrtimer_forward_now(timer, timr->it_interval);
 	hrtimer_restart(timer);
 }
 
@@ -825,7 +824,7 @@ static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
 	hrtimer_setup(&timr->it.real.timer, posix_timer_fn, timr->it_clock, mode);
 
 	if (!absolute)
-		expires = ktime_add_safe(expires, timer->base->get_time());
+		expires = ktime_add_safe(expires, hrtimer_cb_get_time(timer));
 	hrtimer_set_expires(timer, expires);
 
 	if (!sigev_none)

-- 
2.50.1

[PATCH v2 2/9] timers/itimer: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/time/itimer.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 876d389b2e219a10c0dbddb6a06dd3252c502e99..7c6110e964e7ecd19ab8c5c9b81f1b113c1ae7bd 100644
--- a/kernel/time/itimer.c
+++ b/kernel/time/itimer.c
@@ -163,8 +163,7 @@ void posixtimer_rearm_itimer(struct task_struct *tsk)
 	struct hrtimer *tmr = &tsk->signal->real_timer;
 
 	if (!hrtimer_is_queued(tmr) && tsk->signal->it_real_incr != 0) {
-		hrtimer_forward(tmr, tmr->base->get_time(),
-				tsk->signal->it_real_incr);
+		hrtimer_forward_now(tmr, tsk->signal->it_real_incr);
 		hrtimer_restart(tmr);
 	}
 }

-- 
2.50.1

[PATCH v2 3/9] sched/core: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index be00629f0ba4cc5832189c0052b0b632deb4ea2e..4dc12838ad4fdf086b3f3f1168072d6301f51aa3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -917,7 +917,7 @@ void hrtick_start(struct rq *rq, u64 delay)
 	 * doesn't make sense and can cause timer DoS.
 	 */
 	delta = max_t(s64, delay, 10000LL);
-	rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
+	rq->hrtick_time = ktime_add_ns(hrtimer_cb_get_time(timer), delta);
 
 	if (rq == this_rq())
 		__hrtick_restart(rq);

-- 
2.50.1

[PATCH v2 4/9] lib: test_objpool: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 lib/test_objpool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/test_objpool.c b/lib/test_objpool.c
index 8f688187fa8727e26d2d065c46e789ee15fd55b5..6a34a7582fdbf50b5632043ec19e77c8fd4dad78 100644
--- a/lib/test_objpool.c
+++ b/lib/test_objpool.c
@@ -164,7 +164,7 @@ static enum hrtimer_restart ot_hrtimer_handler(struct hrtimer *hrt)
 	/* do bulk-testings for objects pop/push */
 	item->worker(item, 1);
 
-	hrtimer_forward(hrt, hrt->base->get_time(), item->hrtcycle);
+	hrtimer_forward_now(hrt, item->hrtcycle);
 	return HRTIMER_RESTART;
 }
 

-- 
2.50.1

[PATCH v2 5/9] ALSA: hrtimer: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to the equivalent helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
 sound/core/hrtimer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/core/hrtimer.c b/sound/core/hrtimer.c
index c364bd126ac8b311e3ce899e226ff9fd82c4485f..2d5f4d47071f79d7db24c8f004f0f4154808fdd8 100644
--- a/sound/core/hrtimer.c
+++ b/sound/core/hrtimer.c
@@ -44,7 +44,7 @@ static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
 	}
 
 	/* calculate the drift */
-	delta = ktime_sub(hrt->base->get_time(), hrtimer_get_expires(hrt));
+	delta = ktime_sub(hrtimer_cb_get_time(hrt), hrtimer_get_expires(hrt));
 	if (delta > 0)
 		ticks += ktime_divns(delta, ticks * resolution);
 

-- 
2.50.1

[PATCH v2 6/9] media: pwm-ir-tx: Avoid direct access to hrtimer clockbase

[Thomas Weißschuh]

The field timer->base->get_time is a private implementation detail and
should not be accessed outside of the hrtimer core.

Switch to an equivalent higher-level helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/pwm-ir-tx.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
index 84533fdd61aa6ce3c0f8593aaefe5919fd05c7f9..047472dc9244afe0e56e505be20f36fd7d9c449a 100644
--- a/drivers/media/rc/pwm-ir-tx.c
+++ b/drivers/media/rc/pwm-ir-tx.c
@@ -117,7 +117,6 @@ static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,
 static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
 {
 	struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);
-	ktime_t now;
 
 	/*
 	 * If we happen to hit an odd latency spike, loop through the
@@ -139,9 +138,7 @@ static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
 		hrtimer_add_expires_ns(timer, ns);
 
 		pwm_ir->txbuf_index++;
-
-		now = timer->base->get_time();
-	} while (hrtimer_get_expires_tv64(timer) < now);
+	} while (hrtimer_expires_remaining(timer) > 0);
 
 	return HRTIMER_RESTART;
 }

-- 
2.50.1

[PATCH v2 7/9] hrtimer: Use hrtimer_cb_get_time() helper

[Thomas Weißschuh]

Various other helpers contain open-coded implementations of
hrtimer_cb_get_time(). This prevents refactoring the implementation.

Reuse the existing helper.

For this to work, move hrtimer_cb_get_time() a bit up in the file and also
make its argument 'const'.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 include/linux/hrtimer.h | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 1ef867bb8c44b06812d8552441d4092922bfe170..e655502b14e6c4b1a69b67c997132d628bd1470f 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -154,14 +154,14 @@ static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
 	return ktime_to_ns(timer->node.expires);
 }
 
-static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
+static inline ktime_t hrtimer_cb_get_time(const struct hrtimer *timer)
 {
-	return ktime_sub(timer->node.expires, timer->base->get_time());
+	return timer->base->get_time();
 }
 
-static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer)
+static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
 {
-	return timer->base->get_time();
+	return ktime_sub(timer->node.expires, hrtimer_cb_get_time(timer));
 }
 
 static inline int hrtimer_is_hres_active(struct hrtimer *timer)
@@ -200,8 +200,7 @@ __hrtimer_expires_remaining_adjusted(const struct hrtimer *timer, ktime_t now)
 static inline ktime_t
 hrtimer_expires_remaining_adjusted(const struct hrtimer *timer)
 {
-	return __hrtimer_expires_remaining_adjusted(timer,
-						    timer->base->get_time());
+	return __hrtimer_expires_remaining_adjusted(timer, hrtimer_cb_get_time(timer));
 }
 
 #ifdef CONFIG_TIMERFD
@@ -363,7 +362,7 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
 static inline u64 hrtimer_forward_now(struct hrtimer *timer,
 				      ktime_t interval)
 {
-	return hrtimer_forward(timer, timer->base->get_time(), interval);
+	return hrtimer_forward(timer, hrtimer_cb_get_time(timer), interval);
 }
 
 /* Precise sleep: */

-- 
2.50.1

[PATCH v2 8/9] hrtimer: Remove hrtimer_clock_base::get_time

[Thomas Weißschuh]

The get_time() callbacks always need to match the bases clockid.
Instead of maintaining that association twice in hrtimer_bases,
use a helper.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

---
v2: Reorder branches in __hrtimer_cb_get_base()
---
 include/linux/hrtimer.h        |  5 +----
 include/linux/hrtimer_defs.h   |  2 --
 kernel/time/hrtimer.c          | 34 +++++++++++++++++++++++++---------
 kernel/time/timer_list.c       |  2 --
 scripts/gdb/linux/timerlist.py |  2 --
 5 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index e655502b14e6c4b1a69b67c997132d628bd1470f..2cf1bf65b22578499e7de5417dbda1d34cf12fce 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -154,10 +154,7 @@ static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer)
 	return ktime_to_ns(timer->node.expires);
 }
 
-static inline ktime_t hrtimer_cb_get_time(const struct hrtimer *timer)
-{
-	return timer->base->get_time();
-}
+ktime_t hrtimer_cb_get_time(const struct hrtimer *timer);
 
 static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer)
 {
diff --git a/include/linux/hrtimer_defs.h b/include/linux/hrtimer_defs.h
index 84a5045f80f36f88cb47bf23a62a4d0afbd1a2c6..aa49ffa130e57f7278a7d9f96a6d86e6630c69de 100644
--- a/include/linux/hrtimer_defs.h
+++ b/include/linux/hrtimer_defs.h
@@ -41,7 +41,6 @@
  * @seq:		seqcount around __run_hrtimer
  * @running:		pointer to the currently running hrtimer
  * @active:		red black tree root node for the active timers
- * @get_time:		function to retrieve the current time of the clock
  * @offset:		offset of this clock to the monotonic base
  */
 struct hrtimer_clock_base {
@@ -51,7 +50,6 @@ struct hrtimer_clock_base {
 	seqcount_raw_spinlock_t	seq;
 	struct hrtimer		*running;
 	struct timerqueue_head	active;
-	ktime_t			(*get_time)(void);
 	ktime_t			offset;
 } __hrtimer_clock_base_align;
 
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 30899a8cc52c0a9203ce0216fe47f5f19a7bf6ec..fedd1d793f6cdf8923cc8a6707ff793f36b77f26 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -59,6 +59,7 @@
 #define HRTIMER_ACTIVE_ALL	(HRTIMER_ACTIVE_SOFT | HRTIMER_ACTIVE_HARD)
 
 static void retrigger_next_event(void *arg);
+static ktime_t __hrtimer_cb_get_time(clockid_t clock_id);
 
 /*
  * The timer bases:
@@ -76,42 +77,34 @@ DEFINE_PER_CPU(struct hrtimer_cpu_base, hrtimer_bases) =
 		{
 			.index = HRTIMER_BASE_MONOTONIC,
 			.clockid = CLOCK_MONOTONIC,
-			.get_time = &ktime_get,
 		},
 		{
 			.index = HRTIMER_BASE_REALTIME,
 			.clockid = CLOCK_REALTIME,
-			.get_time = &ktime_get_real,
 		},
 		{
 			.index = HRTIMER_BASE_BOOTTIME,
 			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
 		},
 		{
 			.index = HRTIMER_BASE_TAI,
 			.clockid = CLOCK_TAI,
-			.get_time = &ktime_get_clocktai,
 		},
 		{
 			.index = HRTIMER_BASE_MONOTONIC_SOFT,
 			.clockid = CLOCK_MONOTONIC,
-			.get_time = &ktime_get,
 		},
 		{
 			.index = HRTIMER_BASE_REALTIME_SOFT,
 			.clockid = CLOCK_REALTIME,
-			.get_time = &ktime_get_real,
 		},
 		{
 			.index = HRTIMER_BASE_BOOTTIME_SOFT,
 			.clockid = CLOCK_BOOTTIME,
-			.get_time = &ktime_get_boottime,
 		},
 		{
 			.index = HRTIMER_BASE_TAI_SOFT,
 			.clockid = CLOCK_TAI,
-			.get_time = &ktime_get_clocktai,
 		},
 	},
 	.csd = CSD_INIT(retrigger_next_event, NULL)
@@ -1253,7 +1246,7 @@ static int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 	remove_hrtimer(timer, base, true, force_local);
 
 	if (mode & HRTIMER_MODE_REL)
-		tim = ktime_add_safe(tim, base->get_time());
+		tim = ktime_add_safe(tim, __hrtimer_cb_get_time(base->clockid));
 
 	tim = hrtimer_update_lowres(timer, tim, mode);
 
@@ -1588,6 +1581,29 @@ static inline int hrtimer_clockid_to_base(clockid_t clock_id)
 	}
 }
 
+static ktime_t __hrtimer_cb_get_time(clockid_t clock_id)
+{
+	switch (clock_id) {
+	case CLOCK_MONOTONIC:
+		return ktime_get();
+	case CLOCK_REALTIME:
+		return ktime_get_real();
+	case CLOCK_BOOTTIME:
+		return ktime_get_boottime();
+	case CLOCK_TAI:
+		return ktime_get_clocktai();
+	default:
+		WARN(1, "Invalid clockid %d. Using MONOTONIC\n", clock_id);
+		return ktime_get();
+	}
+}
+
+ktime_t hrtimer_cb_get_time(const struct hrtimer *timer)
+{
+	return __hrtimer_cb_get_time(timer->base->clockid);
+}
+EXPORT_SYMBOL_GPL(hrtimer_cb_get_time);
+
 static void __hrtimer_setup(struct hrtimer *timer,
 			    enum hrtimer_restart (*function)(struct hrtimer *),
 			    clockid_t clock_id, enum hrtimer_mode mode)
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index b03d0ada64695058d4c57f3e29d546ba18bff591..488e47e96e93f96a5a18c0f72b8f4df36270943f 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -102,8 +102,6 @@ print_base(struct seq_file *m, struct hrtimer_clock_base *base, u64 now)
 	SEQ_printf(m, "  .index:      %d\n", base->index);
 
 	SEQ_printf(m, "  .resolution: %u nsecs\n", hrtimer_resolution);
-
-	SEQ_printf(m,   "  .get_time:   %ps\n", base->get_time);
 #ifdef CONFIG_HIGH_RES_TIMERS
 	SEQ_printf(m, "  .offset:     %Lu nsecs\n",
 		   (unsigned long long) ktime_to_ns(base->offset));
diff --git a/scripts/gdb/linux/timerlist.py b/scripts/gdb/linux/timerlist.py
index 98445671fe83897d50187f302f844919729388dc..ccc24d30de8063b28e0a3068416af341f8951876 100644
--- a/scripts/gdb/linux/timerlist.py
+++ b/scripts/gdb/linux/timerlist.py
@@ -56,8 +56,6 @@ def print_base(base):
     text += " .index:      {}\n".format(base['index'])
 
     text += " .resolution: {} nsecs\n".format(constants.LX_hrtimer_resolution)
-
-    text += " .get_time:   {}\n".format(base['get_time'])
     if constants.LX_CONFIG_HIGH_RES_TIMERS:
         text += "  .offset:     {} nsecs\n".format(base['offset'])
     text += "active timers:\n"

-- 
2.50.1

[PATCH v2 9/9] hrtimer: Reorder branches in hrtimer_clockid_to_base()

[Thomas Weißschuh]

Align the ordering to the one used for hrtimer_bases.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>

---
v2: New patch
---
 kernel/time/hrtimer.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index fedd1d793f6cdf8923cc8a6707ff793f36b77f26..f383df28c5325919b4d22df383d7fb286ea05874 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1567,10 +1567,10 @@ u64 hrtimer_next_event_without(const struct hrtimer *exclude)
 static inline int hrtimer_clockid_to_base(clockid_t clock_id)
 {
 	switch (clock_id) {
-	case CLOCK_REALTIME:
-		return HRTIMER_BASE_REALTIME;
 	case CLOCK_MONOTONIC:
 		return HRTIMER_BASE_MONOTONIC;
+	case CLOCK_REALTIME:
+		return HRTIMER_BASE_REALTIME;
 	case CLOCK_BOOTTIME:
 		return HRTIMER_BASE_BOOTTIME;
 	case CLOCK_TAI:

-- 
2.50.1