[patch V2 20/50] posix-timers: Consolidate timer setup

From: Thomas Gleixner
Date: Wed Apr 10 2024 - 18:50:27 EST


hrtimer based and CPU timers have their own way to install the new interval
and to reset overrun and signal handling related data.

Create a helper function and do the same operation for all variants.

This also makes the handling of the interval consistent. It's only stored
when the timer is actually armed, i.e. timer->it_value != 0. Before that it
was stored unconditionally for posix CPU timers and conditionally for the
other posix timers.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
kernel/time/posix-cpu-timers.c | 15 +--------------
kernel/time/posix-timers.c | 25 +++++++++++++++++++------
kernel/time/posix-timers.h | 1 +
3 files changed, 21 insertions(+), 20 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -714,21 +714,8 @@ static int posix_cpu_timer_set(struct k_
}

unlock_task_sighand(p, &flags);
- /*
- * Install the new reload setting, and
- * set up the signal and overrun bookkeeping.
- */
- timer->it_interval = timespec64_to_ktime(new->it_interval);

- /*
- * This acts as a modification timestamp for the timer,
- * so any automatic reload attempt will punt on seeing
- * that we have reset the timer manually.
- */
- timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
- ~REQUEUE_PENDING;
- timer->it_overrun_last = 0;
- timer->it_overrun = -1;
+ posix_timer_set_common(timer, new);

/*
* If the new expiry time was already in the past the timer was not
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -856,6 +856,23 @@ static struct k_itimer *timer_wait_runni
return lock_timer(timer_id, flags);
}

+/*
+ * Set up the new interval and reset the signal delivery data
+ */
+void posix_timer_set_common(struct k_itimer *timer, struct itimerspec64 *new_setting)
+{
+ if (new_setting->it_value.tv_sec || new_setting->it_value.tv_nsec)
+ timer->it_interval = timespec64_to_ktime(new_setting->it_interval);
+ else
+ timer->it_interval = 0;
+
+ /* Prevent reloading in case there is a signal pending */
+ timer->it_requeue_pending = (timer->it_requeue_pending + 2) & ~REQUEUE_PENDING;
+ /* Reset overrun accounting */
+ timer->it_overrun_last = 0;
+ timer->it_overrun = -1LL;
+}
+
/* Set a POSIX.1b interval timer. */
int common_timer_set(struct k_itimer *timr, int flags,
struct itimerspec64 *new_setting,
@@ -878,16 +895,12 @@ int common_timer_set(struct k_itimer *ti
return TIMER_RETRY;

timr->it_active = 0;
- timr->it_requeue_pending = (timr->it_requeue_pending + 2) &
- ~REQUEUE_PENDING;
- timr->it_overrun_last = 0;
- timr->it_overrun = -1LL;
+ posix_timer_set_common(timr, new_setting);

- /* Switch off the timer when it_value is zero */
+ /* Keep timer disarmed when it_value is zero */
if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
return 0;

- timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
expires = timespec64_to_ktime(new_setting->it_value);
if (flags & TIMER_ABSTIME)
expires = timens_ktime_to_host(timr->it_clock, expires);
--- a/kernel/time/posix-timers.h
+++ b/kernel/time/posix-timers.h
@@ -42,4 +42,5 @@ void common_timer_get(struct k_itimer *t
int common_timer_set(struct k_itimer *timr, int flags,
struct itimerspec64 *new_setting,
struct itimerspec64 *old_setting);
+void posix_timer_set_common(struct k_itimer *timer, struct itimerspec64 *new_setting);
int common_timer_del(struct k_itimer *timer);