2024-06-10 17:20:58

by Thomas Gleixner

[permalink] [raw]
Subject: [patch V3 07/51] posix-cpu-timers: Split up posix_cpu_timer_get()

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 <[email protected]>
---
V2: Split out into new patch to make review simpler - Frederic
---
kernel/time/posix-cpu-timers.c | 51 +++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 27 deletions(-)

--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -785,33 +785,9 @@ static int posix_cpu_timer_set(struct k_
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
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();
}