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Commit 6f1bc451 authored by Yong Zhang's avatar Yong Zhang Committed by Thomas Gleixner
Browse files

timer: Make try_to_del_timer_sync() the same on SMP and UP 



On UP try_to_del_timer_sync() is mapped to del_timer() which does not
take the running timer callback into account, so it has different
semantics.

Remove the SMP dependency of try_to_del_timer_sync() by using
base->running_timer in the UP case as well.

[ tglx: Removed set_running_timer() inline and tweaked the changelog ]

Signed-off-by: default avatarYong Zhang <yong.zhang0@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 20f33a03

include/linux/timer.h

+2 −2
Original line number Diff line number Diff line
@@ -274,11 +274,11 @@ static inline void timer_stats_timer_clear_start_info(struct timer_list *timer) 


extern void add_timer(struct timer_list *timer);



#ifdef CONFIG_SMP

extern int try_to_del_timer_sync(struct timer_list *timer);



#ifdef CONFIG_SMP

  extern int del_timer_sync(struct timer_list *timer);

#else

# define try_to_del_timer_sync(t)	del_timer(t)

# define del_timer_sync(t)		del_timer(t)

#endif

kernel/timer.c

+3 −14
Original line number Diff line number Diff line
@@ -330,15 +330,6 @@ void set_timer_slack(struct timer_list *timer, int slack_hz) 
}

EXPORT_SYMBOL_GPL(set_timer_slack);





static inline void set_running_timer(struct tvec_base *base,

					struct timer_list *timer)

{

#ifdef CONFIG_SMP

	base->running_timer = timer;

#endif

}



static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)

{

	unsigned long expires = timer->expires;
@@ -923,15 +914,12 @@ int del_timer(struct timer_list *timer) 
}

EXPORT_SYMBOL(del_timer);



#ifdef CONFIG_SMP

/**

 * try_to_del_timer_sync - Try to deactivate a timer

 * @timer: timer do del

 *

 * This function tries to deactivate a timer. Upon successful (ret >= 0)

 * exit the timer is not queued and the handler is not running on any CPU.

 *

 * It must not be called from interrupt contexts.

 */

int try_to_del_timer_sync(struct timer_list *timer)

{
@@ -960,6 +948,7 @@ out: 
}

EXPORT_SYMBOL(try_to_del_timer_sync);



#ifdef CONFIG_SMP

/**

 * del_timer_sync - deactivate a timer and wait for the handler to finish.

 * @timer: the timer to be deactivated
@@ -1098,7 +1087,7 @@ static inline void __run_timers(struct tvec_base *base) 


			timer_stats_account_timer(timer);



			set_running_timer(base, timer);

			base->running_timer = timer;

			detach_timer(timer, 1);



			spin_unlock_irq(&base->lock);
@@ -1106,7 +1095,7 @@ static inline void __run_timers(struct tvec_base *base) 
			spin_lock_irq(&base->lock);

		}

	}

	set_running_timer(base, NULL);

	base->running_timer = NULL;

	spin_unlock_irq(&base->lock);

}