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 <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>

diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index e9c6f9d0e42ce42e837e9d83c046031ff797a4f8..558be8d53e474ffb8d3e3ed2b5e3e1d83efdf889 100644 (file)
--- 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_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();
 }