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| author | Ingo Molnar <mingo@elte.hu> | 2009-07-03 13:29:34 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2014-05-14 18:38:09 (GMT) |
| commit | 10b462c0d388001ad9903234807d87dd1c57e617 (patch) | |
| tree | 39440efa18ea0dae40c3310c97ff9a2041e2f0a0 /kernel/posix-timers.c | |
| parent | 946769588ffc25e0f066f980ef58dee189741b5d (diff) | |
| download | linux-fsl-qoriq-10b462c0d388001ad9903234807d87dd1c57e617.tar.xz | |
hrtimers: prepare full preemption
Make cancellation of a running callback in softirq context safe
against preemption.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/posix-timers.c')
| -rw-r--r-- | kernel/posix-timers.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 68af2dc..a22b931 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -818,6 +818,20 @@ SYSCALL_DEFINE1(timer_getoverrun, timer_t, timer_id) return overrun; } +/* + * Protected by RCU! + */ +static void timer_wait_for_callback(struct k_clock *kc, struct k_itimer *timr) +{ +#ifdef CONFIG_PREEMPT_RT_FULL + if (kc->timer_set == common_timer_set) + hrtimer_wait_for_timer(&timr->it.real.timer); + else + /* FIXME: Whacky hack for posix-cpu-timers */ + schedule_timeout(1); +#endif +} + /* Set a POSIX.1b interval timer. */ /* timr->it_lock is taken. */ static int @@ -895,6 +909,7 @@ retry: if (!timr) return -EINVAL; + rcu_read_lock(); kc = clockid_to_kclock(timr->it_clock); if (WARN_ON_ONCE(!kc || !kc->timer_set)) error = -EINVAL; @@ -903,9 +918,12 @@ retry: unlock_timer(timr, flag); if (error == TIMER_RETRY) { + timer_wait_for_callback(kc, timr); rtn = NULL; // We already got the old time... + rcu_read_unlock(); goto retry; } + rcu_read_unlock(); if (old_setting && !error && copy_to_user(old_setting, &old_spec, sizeof (old_spec))) @@ -943,10 +961,15 @@ retry_delete: if (!timer) return -EINVAL; + rcu_read_lock(); if (timer_delete_hook(timer) == TIMER_RETRY) { unlock_timer(timer, flags); + timer_wait_for_callback(clockid_to_kclock(timer->it_clock), + timer); + rcu_read_unlock(); goto retry_delete; } + rcu_read_unlock(); spin_lock(¤t->sighand->siglock); list_del(&timer->list); @@ -972,8 +995,18 @@ static void itimer_delete(struct k_itimer *timer) retry_delete: spin_lock_irqsave(&timer->it_lock, flags); + /* On RT we can race with a deletion */ + if (!timer->it_signal) { + unlock_timer(timer, flags); + return; + } + if (timer_delete_hook(timer) == TIMER_RETRY) { + rcu_read_lock(); unlock_timer(timer, flags); + timer_wait_for_callback(clockid_to_kclock(timer->it_clock), + timer); + rcu_read_unlock(); goto retry_delete; } list_del(&timer->list); |