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Commit d8e794df authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: set delayed_work->timer function on initialization 



delayed_work->timer.function is currently initialized during
queue_delayed_work_on().  Export delayed_work_timer_fn() and set
delayed_work timer function during delayed_work initialization
together with other fields.

This ensures the timer function is always valid on an initialized
delayed_work.  This is to help mod_delayed_work() implementation.

To detect delayed_work users which diddle with the internal timer,
trigger WARN if timer function doesn't match on queue.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 8930caba

include/linux/workqueue.h

+11 −2
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ struct workqueue_struct; 


struct work_struct;

typedef void (*work_func_t)(struct work_struct *work);

void delayed_work_timer_fn(unsigned long __data);



/*

 * The first word is the work queue pointer and the flags rolled into
@@ -124,12 +125,14 @@ struct execute_work { 


#define __DELAYED_WORK_INITIALIZER(n, f) {			\

	.work = __WORK_INITIALIZER((n).work, (f)),		\

	.timer = TIMER_INITIALIZER(NULL, 0, 0),			\

	.timer = TIMER_INITIALIZER(delayed_work_timer_fn,	\

				0, (unsigned long)&(n)),	\

	}



#define __DEFERRED_WORK_INITIALIZER(n, f) {			\

	.work = __WORK_INITIALIZER((n).work, (f)),		\

	.timer = TIMER_DEFERRED_INITIALIZER(NULL, 0, 0),	\

	.timer = TIMER_DEFERRED_INITIALIZER(delayed_work_timer_fn, \

				0, (unsigned long)&(n)),	\

	}



#define DECLARE_WORK(n, f)					\
@@ -207,18 +210,24 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; } 
	do {							\

		INIT_WORK(&(_work)->work, (_func));		\

		init_timer(&(_work)->timer);			\

		(_work)->timer.function = delayed_work_timer_fn;\

		(_work)->timer.data = (unsigned long)(_work);	\

	} while (0)



#define INIT_DELAYED_WORK_ONSTACK(_work, _func)			\

	do {							\

		INIT_WORK_ONSTACK(&(_work)->work, (_func));	\

		init_timer_on_stack(&(_work)->timer);		\

		(_work)->timer.function = delayed_work_timer_fn;\

		(_work)->timer.data = (unsigned long)(_work);	\

	} while (0)



#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func)		\

	do {							\

		INIT_WORK(&(_work)->work, (_func));		\

		init_timer_deferrable(&(_work)->timer);		\

		(_work)->timer.function = delayed_work_timer_fn;\

		(_work)->timer.data = (unsigned long)(_work);	\

	} while (0)



/**

kernel/workqueue.c

+4 −3
Original line number Diff line number Diff line
@@ -1112,7 +1112,7 @@ bool queue_work(struct workqueue_struct *wq, struct work_struct *work) 
}

EXPORT_SYMBOL_GPL(queue_work);



static void delayed_work_timer_fn(unsigned long __data)

void delayed_work_timer_fn(unsigned long __data)

{

	struct delayed_work *dwork = (struct delayed_work *)__data;

	struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
@@ -1121,6 +1121,7 @@ static void delayed_work_timer_fn(unsigned long __data) 
	__queue_work(smp_processor_id(), cwq->wq, &dwork->work);

	local_irq_enable();

}

EXPORT_SYMBOL_GPL(delayed_work_timer_fn);



/**

 * queue_delayed_work_on - queue work on specific CPU after delay
@@ -1145,6 +1146,8 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 
	if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {

		unsigned int lcpu;



		WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||

			     timer->data != (unsigned long)dwork);

		BUG_ON(timer_pending(timer));

		BUG_ON(!list_empty(&work->entry));
@@ -1168,8 +1171,6 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq, 
		set_work_cwq(work, get_cwq(lcpu, wq), 0);



		timer->expires = jiffies + delay;

		timer->data = (unsigned long)dwork;

		timer->function = delayed_work_timer_fn;



		if (unlikely(cpu >= 0))

			add_timer_on(timer, cpu);