posix-cpu-timers: Handle SIGEV_NONE timers correctly in timer_set()

Expired SIGEV_NONE oneshot timers must return 0 nsec for the expiry time in
timer_get(), but the posix CPU timer implementation returns 1 nsec.

Add the missing conditional.

This will be cleaned up in a follow up patch.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
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 d70879d502f909f050cf20962925741e11505eab..cf8904423cba3c0653e84d954ca1c46a35fb02c4 100644 (file)
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -623,6 +623,7 @@ static void cpu_timer_fire(struct k_itimer *timer)
 static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
                               struct itimerspec64 *new, struct itimerspec64 *old)
 {
+       bool sigev_none = timer->it_sigev_notify == SIGEV_NONE;
        clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
        u64 old_expires, new_expires, old_incr, val;
        struct cpu_timer *ctmr = &timer->it.cpu;
@@ -706,7 +707,16 @@ static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
                                old_expires = exp - val;
                                old->it_value = ns_to_timespec64(old_expires);
                        } else {
-                               old->it_value.tv_nsec = 1;
+                               /*
+                                * A single shot SIGEV_NONE timer must return 0, when it is
+                                * expired! Timers which have a real signal delivery mode
+                                * must return a remaining time greater than 0 because the
+                                * signal has not yet been delivered.
+                                */
+                               if (sigev_none)
+                                       old->it_value.tv_nsec = 0;
+                               else
+                                       old->it_value.tv_nsec = 1;
                                old->it_value.tv_sec = 0;
                        }
                }