posix-timers: Make use of cancel/arm callbacks

Replace the hrtimer calls by calls to the new try_to_cancel()/arm() kclock
callbacks and move the hrtimer specific implementation into the
corresponding callback functions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20170530211657.355396667@linutronix.de

diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 0332f7a60fd6de3eef482f14d49ec59d525b8ac8..8acc9ee2c2d6e7f11b33565ed8b637a027c63d5d 100644 (file)
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -744,25 +744,49 @@ SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id)
        return overrun;
 }
 
+static void common_hrtimer_arm(struct k_itimer *timr, ktime_t expires,
+                              bool absolute, bool sigev_none)
+{
+       struct hrtimer *timer = &timr->it.real.timer;
+       enum hrtimer_mode mode;
+
+       mode = absolute ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
+       hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
+       timr->it.real.timer.function = posix_timer_fn;
+
+       if (!absolute)
+               expires = ktime_add_safe(expires, timer->base->get_time());
+       hrtimer_set_expires(timer, expires);
+
+       if (!sigev_none)
+               hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+}
+
+static int common_hrtimer_try_to_cancel(struct k_itimer *timr)
+{
+       return hrtimer_try_to_cancel(&timr->it.real.timer);
+}
+
 /* Set a POSIX.1b interval timer. */
-/* timr->it_lock is taken. */
 static int
 common_timer_set(struct k_itimer *timr, int flags,
-                struct itimerspec64 *new_setting, struct itimerspec64 *old_setting)
+                struct itimerspec64 *new_setting,
+                struct itimerspec64 *old_setting)
 {
-       struct hrtimer *timer = &timr->it.real.timer;
-       enum hrtimer_mode mode;
+       const struct k_clock *kc = timr->kclock;
+       bool sigev_none;
+       ktime_t expires;
 
        if (old_setting)
                common_timer_get(timr, old_setting);
 
-       /* disable the timer */
+       /* Prevent rearming by clearing the interval */
        timr->it_interval = 0;
        /*
-        * careful here.  If smp we could be in the "fire" routine which will
-        * be spinning as we hold the lock.  But this is ONLY an SMP issue.
+        * Careful here. On SMP systems the timer expiry function could be
+        * active and spinning on timr->it_lock.
         */
-       if (hrtimer_try_to_cancel(timer) < 0)
+       if (kc->timer_try_to_cancel(timr) < 0)
                return TIMER_RETRY;
 
        timr->it_active = 0;
@@ -770,30 +794,16 @@ common_timer_set(struct k_itimer *timr, int flags,
                ~REQUEUE_PENDING;
        timr->it_overrun_last = 0;
 
-       /* switch off the timer when it_value is zero */
+       /* Switch off the timer when it_value is zero */
        if (!new_setting->it_value.tv_sec && !new_setting->it_value.tv_nsec)
                return 0;
 
-       mode = flags & TIMER_ABSTIME ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL;
-       hrtimer_init(&timr->it.real.timer, timr->it_clock, mode);
-       timr->it.real.timer.function = posix_timer_fn;
-
-       hrtimer_set_expires(timer, timespec64_to_ktime(new_setting->it_value));
-
-       /* Convert interval */
        timr->it_interval = timespec64_to_ktime(new_setting->it_interval);
+       expires = timespec64_to_ktime(new_setting->it_value);
+       sigev_none = (timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE;
 
-       /* SIGEV_NONE timers are not queued ! See common_timer_get */
-       if (((timr->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE)) {
-               /* Setup correct expiry time for relative timers */
-               if (mode == HRTIMER_MODE_REL) {
-                       hrtimer_add_expires(timer, timer->base->get_time());
-               }
-               return 0;
-       }
-
-       timr->it_active = 1;
-       hrtimer_start_expires(timer, mode);
+       kc->timer_arm(timr, expires, flags & TIMER_ABSTIME, sigev_none);
+       timr->it_active = !sigev_none;
        return 0;
 }
 
@@ -847,9 +857,10 @@ retry:
 
 static int common_timer_del(struct k_itimer *timer)
 {
-       timer->it_interval = 0;
+       const struct k_clock *kc = timer->kclock;
 
-       if (hrtimer_try_to_cancel(&timer->it.real.timer) < 0)
+       timer->it_interval = 0;
+       if (kc->timer_try_to_cancel(timer) < 0)
                return TIMER_RETRY;
        timer->it_active = 0;
        return 0;
@@ -1063,76 +1074,84 @@ long clock_nanosleep_restart(struct restart_block *restart_block)
 }
 
 static const struct k_clock clock_realtime = {
-       .clock_getres   = posix_get_hrtimer_res,
-       .clock_get      = posix_clock_realtime_get,
-       .clock_set      = posix_clock_realtime_set,
-       .clock_adj      = posix_clock_realtime_adj,
-       .nsleep         = common_nsleep,
-       .nsleep_restart = hrtimer_nanosleep_restart,
-       .timer_create   = common_timer_create,
-       .timer_set      = common_timer_set,
-       .timer_get      = common_timer_get,
-       .timer_del      = common_timer_del,
-       .timer_rearm    = common_hrtimer_rearm,
-       .timer_forward  = common_hrtimer_forward,
-       .timer_remaining= common_hrtimer_remaining,
+       .clock_getres           = posix_get_hrtimer_res,
+       .clock_get              = posix_clock_realtime_get,
+       .clock_set              = posix_clock_realtime_set,
+       .clock_adj              = posix_clock_realtime_adj,
+       .nsleep                 = common_nsleep,
+       .nsleep_restart         = hrtimer_nanosleep_restart,
+       .timer_create           = common_timer_create,
+       .timer_set              = common_timer_set,
+       .timer_get              = common_timer_get,
+       .timer_del              = common_timer_del,
+       .timer_rearm            = common_hrtimer_rearm,
+       .timer_forward          = common_hrtimer_forward,
+       .timer_remaining        = common_hrtimer_remaining,
+       .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
+       .timer_arm              = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_monotonic = {
-       .clock_getres   = posix_get_hrtimer_res,
-       .clock_get      = posix_ktime_get_ts,
-       .nsleep         = common_nsleep,
-       .nsleep_restart = hrtimer_nanosleep_restart,
-       .timer_create   = common_timer_create,
-       .timer_set      = common_timer_set,
-       .timer_get      = common_timer_get,
-       .timer_del      = common_timer_del,
-       .timer_rearm    = common_hrtimer_rearm,
-       .timer_forward  = common_hrtimer_forward,
-       .timer_remaining= common_hrtimer_remaining,
+       .clock_getres           = posix_get_hrtimer_res,
+       .clock_get              = posix_ktime_get_ts,
+       .nsleep                 = common_nsleep,
+       .nsleep_restart         = hrtimer_nanosleep_restart,
+       .timer_create           = common_timer_create,
+       .timer_set              = common_timer_set,
+       .timer_get              = common_timer_get,
+       .timer_del              = common_timer_del,
+       .timer_rearm            = common_hrtimer_rearm,
+       .timer_forward          = common_hrtimer_forward,
+       .timer_remaining        = common_hrtimer_remaining,
+       .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
+       .timer_arm              = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_monotonic_raw = {
-       .clock_getres   = posix_get_hrtimer_res,
-       .clock_get      = posix_get_monotonic_raw,
+       .clock_getres           = posix_get_hrtimer_res,
+       .clock_get              = posix_get_monotonic_raw,
 };
 
 static const struct k_clock clock_realtime_coarse = {
-       .clock_getres   = posix_get_coarse_res,
-       .clock_get      = posix_get_realtime_coarse,
+       .clock_getres           = posix_get_coarse_res,
+       .clock_get              = posix_get_realtime_coarse,
 };
 
 static const struct k_clock clock_monotonic_coarse = {
-       .clock_getres   = posix_get_coarse_res,
-       .clock_get      = posix_get_monotonic_coarse,
+       .clock_getres           = posix_get_coarse_res,
+       .clock_get              = posix_get_monotonic_coarse,
 };
 
 static const struct k_clock clock_tai = {
-       .clock_getres   = posix_get_hrtimer_res,
-       .clock_get      = posix_get_tai,
-       .nsleep         = common_nsleep,
-       .nsleep_restart = hrtimer_nanosleep_restart,
-       .timer_create   = common_timer_create,
-       .timer_set      = common_timer_set,
-       .timer_get      = common_timer_get,
-       .timer_del      = common_timer_del,
-       .timer_rearm    = common_hrtimer_rearm,
-       .timer_forward  = common_hrtimer_forward,
-       .timer_remaining= common_hrtimer_remaining,
+       .clock_getres           = posix_get_hrtimer_res,
+       .clock_get              = posix_get_tai,
+       .nsleep                 = common_nsleep,
+       .nsleep_restart         = hrtimer_nanosleep_restart,
+       .timer_create           = common_timer_create,
+       .timer_set              = common_timer_set,
+       .timer_get              = common_timer_get,
+       .timer_del              = common_timer_del,
+       .timer_rearm            = common_hrtimer_rearm,
+       .timer_forward          = common_hrtimer_forward,
+       .timer_remaining        = common_hrtimer_remaining,
+       .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
+       .timer_arm              = common_hrtimer_arm,
 };
 
 static const struct k_clock clock_boottime = {
-       .clock_getres   = posix_get_hrtimer_res,
-       .clock_get      = posix_get_boottime,
-       .nsleep         = common_nsleep,
-       .nsleep_restart = hrtimer_nanosleep_restart,
-       .timer_create   = common_timer_create,
-       .timer_set      = common_timer_set,
-       .timer_get      = common_timer_get,
-       .timer_del      = common_timer_del,
-       .timer_rearm    = common_hrtimer_rearm,
-       .timer_forward  = common_hrtimer_forward,
-       .timer_remaining= common_hrtimer_remaining,
+       .clock_getres           = posix_get_hrtimer_res,
+       .clock_get              = posix_get_boottime,
+       .nsleep                 = common_nsleep,
+       .nsleep_restart         = hrtimer_nanosleep_restart,
+       .timer_create           = common_timer_create,
+       .timer_set              = common_timer_set,
+       .timer_get              = common_timer_get,
+       .timer_del              = common_timer_del,
+       .timer_rearm            = common_hrtimer_rearm,
+       .timer_forward          = common_hrtimer_forward,
+       .timer_remaining        = common_hrtimer_remaining,
+       .timer_try_to_cancel    = common_hrtimer_try_to_cancel,
+       .timer_arm              = common_hrtimer_arm,
 };
 
 static const struct k_clock * const posix_clocks[] = {