del_timer() and __run_timers() use smp_wmb() before
clearing timer's pending flag. It was needed because
__mod_timer() did not locked old_base if the timer is
not pending, so __mod_timer()->internal_add_timer()
can race with del_timer()->list_del().
With the previous patch these functions are serialized
through base->lock, so the barrier can be killed.
Still needed in del_timer_sync(), because it clears ->_base.
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
--- 2.6.12-rc1/kernel/timer.c~4_BARR 2005-03-19 22:26:50.000000000 +0300
+++ 2.6.12-rc1/kernel/timer.c 2005-03-19 22:28:34.000000000 +0300
@@ -337,8 +337,6 @@ repeat:
goto repeat;
}
list_del(&timer->entry);
- /* Need to make sure that anybody who sees a NULL base also sees the
list ops */
- smp_wmb();
__set_base(timer, base, 0);
spin_unlock_irqrestore(&base->lock, flags);
@@ -496,7 +494,6 @@ repeat:
list_del(&timer->entry);
set_running_timer(base, timer);
- smp_wmb();
__set_base(timer, base, 0);
spin_unlock_irq(&base->lock);
{
-
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