From: Oleg Nesterov Date: Thu, 23 Jun 2005 07:09:00 +0000 (-0700) Subject: [PATCH] posix-timers: use try_to_del_timer_sync() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f972be33ce6a08b5f096ba013c7459a3a82f5f39;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git [PATCH] posix-timers: use try_to_del_timer_sync() sys_timer_settime/sys_timer_delete needs to delete k_itimer->real.timer synchronously while holding ->it_lock, which is also locked in posix_timer_fn. This patch removes timer_active/set_timer_inactive which plays with timer_list's internals in favour of using try_to_del_timer_sync(), which was introduced in the previous patch. Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index cabb63fc9e1..5b7b4736d82 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -88,23 +88,6 @@ static kmem_cache_t *posix_timers_cache; static struct idr posix_timers_id; static DEFINE_SPINLOCK(idr_lock); -/* - * Just because the timer is not in the timer list does NOT mean it is - * inactive. It could be in the "fire" routine getting a new expire time. - */ -#define TIMER_INACTIVE 1 - -#ifdef CONFIG_SMP -# define timer_active(tmr) \ - ((tmr)->it.real.timer.entry.prev != (void *)TIMER_INACTIVE) -# define set_timer_inactive(tmr) \ - do { \ - (tmr)->it.real.timer.entry.prev = (void *)TIMER_INACTIVE; \ - } while (0) -#else -# define timer_active(tmr) BARFY // error to use outside of SMP -# define set_timer_inactive(tmr) do { } while (0) -#endif /* * we assume that the new SIGEV_THREAD_ID shares no bits with the other * SIGEV values. Here we put out an error if this assumption fails. @@ -226,7 +209,6 @@ static inline int common_timer_create(struct k_itimer *new_timer) init_timer(&new_timer->it.real.timer); new_timer->it.real.timer.data = (unsigned long) new_timer; new_timer->it.real.timer.function = posix_timer_fn; - set_timer_inactive(new_timer); return 0; } @@ -480,7 +462,6 @@ static void posix_timer_fn(unsigned long __data) int do_notify = 1; spin_lock_irqsave(&timr->it_lock, flags); - set_timer_inactive(timr); if (!list_empty(&timr->it.real.abs_timer_entry)) { spin_lock(&abs_list.lock); do { @@ -983,8 +964,8 @@ common_timer_set(struct k_itimer *timr, int flags, * 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. */ + if (try_to_del_timer_sync(&timr->it.real.timer) < 0) { #ifdef CONFIG_SMP - if (timer_active(timr) && !del_timer(&timr->it.real.timer)) /* * It can only be active if on an other cpu. Since * we have cleared the interval stuff above, it should @@ -994,11 +975,9 @@ common_timer_set(struct k_itimer *timr, int flags, * a "retry" exit status. */ return TIMER_RETRY; - - set_timer_inactive(timr); -#else - del_timer(&timr->it.real.timer); #endif + } + remove_from_abslist(timr); timr->it_requeue_pending = (timr->it_requeue_pending + 2) & @@ -1083,8 +1062,9 @@ retry: static inline int common_timer_del(struct k_itimer *timer) { timer->it.real.incr = 0; + + if (try_to_del_timer_sync(&timer->it.real.timer) < 0) { #ifdef CONFIG_SMP - if (timer_active(timer) && !del_timer(&timer->it.real.timer)) /* * It can only be active if on an other cpu. Since * we have cleared the interval stuff above, it should @@ -1094,9 +1074,9 @@ static inline int common_timer_del(struct k_itimer *timer) * a "retry" exit status. */ return TIMER_RETRY; -#else - del_timer(&timer->it.real.timer); #endif + } + remove_from_abslist(timer); return 0;