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Commit 1118e2cd authored by Yong Zhang's avatar Yong Zhang Committed by Thomas Gleixner
Browse files

timer: Del_timer_sync() can be used in softirq context 



Actually we have used del_timer_sync() in softirq context for a long time,
e.g. in __dst_free()::cancel_delayed_work().

So change the comments of it to warn on hardirq context only, and make
lockdep know about this change.

Signed-off-by: default avatarYong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 6f1bc451

kernel/timer.c

+3 −5
Original line number Original line Diff line number Diff line
@@ -959,7 +959,7 @@ EXPORT_SYMBOL(try_to_del_timer_sync); 
 *

 *

 * Synchronization rules: Callers must prevent restarting of the timer,

 * Synchronization rules: Callers must prevent restarting of the timer,

 * otherwise this function is meaningless. It must not be called from

 * otherwise this function is meaningless. It must not be called from

 * interrupt contexts. The caller must not hold locks which would prevent

 * hardirq contexts. The caller must not hold locks which would prevent

 * completion of the timer's handler. The timer's handler must not call

 * completion of the timer's handler. The timer's handler must not call

 * add_timer_on(). Upon exit the timer is not queued and the handler is

 * add_timer_on(). Upon exit the timer is not queued and the handler is

 * not running on any CPU.

 * not running on any CPU.
@@ -969,12 +969,10 @@ EXPORT_SYMBOL(try_to_del_timer_sync); 
int del_timer_sync(struct timer_list *timer)

int del_timer_sync(struct timer_list *timer)

{

{

#ifdef CONFIG_LOCKDEP

#ifdef CONFIG_LOCKDEP

	unsigned long flags;

	local_bh_disable();



	local_irq_save(flags);

	lock_map_acquire(&timer->lockdep_map);

	lock_map_acquire(&timer->lockdep_map);

	lock_map_release(&timer->lockdep_map);

	lock_map_release(&timer->lockdep_map);

	local_irq_restore(flags);

	local_bh_enable();

#endif

#endif





	for (;;) {

	for (;;) {