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posix-cpu-timers: Split up posix_cpu_timer_get()

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In preparation for addressing issues in the timer_get() and timer_set()
functions of posix CPU timers.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
This commit is contained in:
Thomas Gleixner 2024-06-10 18:42:14 +02:00 committed by Frederic Weisbecker
parent 73339b82f8
commit d859704bf1
1 changed files with 24 additions and 27 deletions
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51
kernel/time/posix-cpu-timers.c
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@ -785,33 +785,9 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
return ret;
}
static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
static void __posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp, u64 now)
{
clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
struct cpu_timer *ctmr = &timer->it.cpu;
u64 now, expires = cpu_timer_getexpires(ctmr);
struct task_struct *p;
rcu_read_lock();
p = cpu_timer_task_rcu(timer);
if (!p)
goto out;
/*
* Easy part: convert the reload time.
*/
itp->it_interval = ktime_to_timespec64(timer->it_interval);
if (!expires)
goto out;
/*
* Sample the clock to take the difference with the expiry time.
*/
if (CPUCLOCK_PERTHREAD(timer->it_clock))
now = cpu_clock_sample(clkid, p);
else
now = cpu_clock_sample_group(clkid, p, false);
u64 expires = cpu_timer_getexpires(&timer->it.cpu);
if (now < expires) {
itp->it_value = ns_to_timespec64(expires - now);
@ -823,7 +799,28 @@ static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp
itp->it_value.tv_nsec = 1;
itp->it_value.tv_sec = 0;
}
out:
}
static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
{
clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
struct task_struct *p;
u64 now;
rcu_read_lock();
p = cpu_timer_task_rcu(timer);
if (p) {
itp->it_interval = ktime_to_timespec64(timer->it_interval);
if (cpu_timer_getexpires(&timer->it.cpu)) {
if (CPUCLOCK_PERTHREAD(timer->it_clock))
now = cpu_clock_sample(clkid, p);
else
now = cpu_clock_sample_group(clkid, p, false);
__posix_cpu_timer_get(timer, itp, now);
}
}
rcu_read_unlock();
}