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 <[email protected]>
--- 2.6.12-rc4-mm2/kernel/posix-timers.c~2_USE 2005-04-30 18:05:29.000000000 +0400
+++ 2.6.12-rc4-mm2/kernel/posix-timers.c 2005-05-22 18:34:10.000000000 +0400
@@ -89,23 +89,6 @@ 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(st
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
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,
* 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,
* 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(struc
* a "retry" exit status.
*/
return TIMER_RETRY;
-#else
- del_timer(&timer->it.real.timer);
#endif
+ }
+
remove_from_abslist(timer);
return 0;
-
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