alarmtimer: Convert posix timer functions to alarm_start_timer()

Use the new alarm_start_timer() for arming and rearming posix interval
timers and for clock_nanosleep() so that already expired timers do not go
through the full timer interrupt cycle.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260408114952.400451460@kernel.org

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 2348b0839114cf3a60f75f736d0e64929311553a..9baa69cfa15823534ab62113d599480a18c8ca71 100644 (file)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -560,8 +560,7 @@ static bool alarm_timer_rearm(struct k_itimer *timr)
        struct alarm *alarm = &timr->it.alarm.alarmtimer;
 
        timr->it_overrun += alarm_forward_now(alarm, timr->it_interval);
-       alarm_start(alarm, alarm->node.expires);
-       return true;
+       return alarm_start_timer(alarm, alarm->node.expires, false);
 }
 
 /**
@@ -625,11 +624,16 @@ static bool alarm_timer_arm(struct k_itimer *timr, ktime_t expires,
 
        if (!absolute)
                expires = ktime_add_safe(expires, base->get_ktime());
-       if (sigev_none)
+
+       /*
+        * sigev_none needs to update the expires value and pretend
+        * that the timer is queued
+        */
+       if (sigev_none) {
                alarm->node.expires = expires;
-       else
-               alarm_start(&timr->it.alarm.alarmtimer, expires);
-       return true;
+               return true;
+       }
+       return alarm_start_timer(&timr->it.alarm.alarmtimer, expires, false);
 }
 
 /**
@@ -736,7 +740,9 @@ static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp,
        alarm->data = (void *)current;
        do {
                set_current_state(TASK_INTERRUPTIBLE);
-               alarm_start(alarm, absexp);
+               if (!alarm_start_timer(alarm, absexp, false))
+                       alarm->data = NULL;
+
                if (likely(alarm->data))
                        schedule();