posix-timers: check ->it_signal instead of ->it_pid to validate the timer
Impact: clean up, speed up ->it_pid (was ->it_process) has also a special meaning: if it is NULL, the timer is under deletion or it wasn't initialized yet. We can check ->it_signal != NULL instead, this way we can - simplify sys_timer_create() a bit - remove yet another check from lock_timer() - move put_pid(->it_pid) into release_posix_timer() which runs outside of ->it_lock Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -464,6 +464,7 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
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idr_remove(&posix_timers_id, tmr->it_id);
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spin_unlock_irqrestore(&idr_lock, flags);
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}
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put_pid(tmr->it_pid);
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sigqueue_free(tmr->sigq);
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kmem_cache_free(posix_timers_cache, tmr);
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}
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@ -477,7 +478,6 @@ sys_timer_create(const clockid_t which_clock,
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{
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struct k_itimer *new_timer;
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int error, new_timer_id;
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struct pid *it_pid;
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sigevent_t event;
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int it_id_set = IT_ID_NOT_SET;
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@ -531,9 +531,9 @@ sys_timer_create(const clockid_t which_clock,
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goto out;
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}
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rcu_read_lock();
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it_pid = get_pid(good_sigevent(&event));
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new_timer->it_pid = get_pid(good_sigevent(&event));
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rcu_read_unlock();
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if (!it_pid) {
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if (!new_timer->it_pid) {
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error = -EINVAL;
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goto out;
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}
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@ -541,7 +541,7 @@ sys_timer_create(const clockid_t which_clock,
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event.sigev_notify = SIGEV_SIGNAL;
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event.sigev_signo = SIGALRM;
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event.sigev_value.sival_int = new_timer->it_id;
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it_pid = get_pid(task_tgid(current));
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new_timer->it_pid = get_pid(task_tgid(current));
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}
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new_timer->it_sigev_notify = event.sigev_notify;
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@ -551,7 +551,6 @@ sys_timer_create(const clockid_t which_clock,
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new_timer->sigq->info.si_code = SI_TIMER;
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spin_lock_irq(¤t->sighand->siglock);
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new_timer->it_pid = it_pid;
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new_timer->it_signal = current->signal;
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list_add(&new_timer->list, ¤t->signal->posix_timers);
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spin_unlock_irq(¤t->sighand->siglock);
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@ -587,7 +586,7 @@ static struct k_itimer *lock_timer(timer_t timer_id, unsigned long *flags)
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timr = idr_find(&posix_timers_id, (int)timer_id);
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if (timr) {
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spin_lock(&timr->it_lock);
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if (timr->it_pid && timr->it_signal == current->signal) {
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if (timr->it_signal == current->signal) {
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spin_unlock(&idr_lock);
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return timr;
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}
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@ -834,8 +833,7 @@ retry_delete:
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* This keeps any tasks waiting on the spin lock from thinking
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* they got something (see the lock code above).
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*/
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put_pid(timer->it_pid);
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timer->it_pid = NULL;
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timer->it_signal = NULL;
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unlock_timer(timer, flags);
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release_posix_timer(timer, IT_ID_SET);
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@ -861,8 +859,7 @@ retry_delete:
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* This keeps any tasks waiting on the spin lock from thinking
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* they got something (see the lock code above).
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*/
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put_pid(timer->it_pid);
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timer->it_pid = NULL;
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timer->it_signal = NULL;
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unlock_timer(timer, flags);
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release_posix_timer(timer, IT_ID_SET);
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