workqueue: use irqsafe timer for delayed_work (e0aecdd8) · Commits · 戴 / test

include/linux/workqueue.h

+5 −3

Original line number	Diff line number	Diff line
		@@ -136,7 +136,8 @@ struct execute_work {
		#define __DELAYED_WORK_INITIALIZER(n, f, tflags) { \
		.work = __WORK_INITIALIZER((n).work, (f)), \
		.timer = __TIMER_INITIALIZER(delayed_work_timer_fn, \
		0, (unsigned long)&(n), (tflags)), \
		0, (unsigned long)&(n), \
		(tflags) \| TIMER_IRQSAFE), \
		}

		#define DECLARE_WORK(n, f) \
		@@ -214,7 +215,8 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
		do { \
		INIT_WORK(&(_work)->work, (_func)); \
		__setup_timer(&(_work)->timer, delayed_work_timer_fn, \
		(unsigned long)(_work), (_tflags)); \
		(unsigned long)(_work), \
		(_tflags) \| TIMER_IRQSAFE); \
		} while (0)

		#define __INIT_DELAYED_WORK_ONSTACK(_work, _func, _tflags) \
		@@ -223,7 +225,7 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
		__setup_timer_on_stack(&(_work)->timer, \
		delayed_work_timer_fn, \
		(unsigned long)(_work), \
		(_tflags)); \
		(_tflags) \| TIMER_IRQSAFE); \
		} while (0)

		#define INIT_DELAYED_WORK(_work, _func) \

kernel/workqueue.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -1048,16 +1048,14 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color,
		* for arbitrarily long
		*
		* On >= 0 return, the caller owns @work's PENDING bit. To avoid getting
		* preempted while holding PENDING and @work off queue, preemption must be
		* disabled on entry. This ensures that we don't return -EAGAIN while
		* another task is preempted in this function.
		* interrupted while holding PENDING and @work off queue, irq must be
		* disabled on entry. This, combined with delayed_work->timer being
		* irqsafe, ensures that we return -EAGAIN for finite short period of time.
		*
		* On successful return, >= 0, irq is disabled and the caller is
		* responsible for releasing it using local_irq_restore(*@flags).
		*
		* This function is safe to call from any context other than IRQ handler.
		* An IRQ handler may run on top of delayed_work_timer_fn() which can make
		* this function return -EAGAIN perpetually.
		* This function is safe to call from any context including IRQ handler.
		*/
		static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
		unsigned long *flags)
		@@ -1072,6 +1070,11 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
		if (is_dwork) {
		struct delayed_work *dwork = to_delayed_work(work);

		/*
		* dwork->timer is irqsafe. If del_timer() fails, it's
		* guaranteed that the timer is not queued anywhere and not
		* running on the local CPU.
		*/
		if (likely(del_timer(&dwork->timer)))
		return 1;
		}
		@@ -1327,9 +1330,8 @@ 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);

		local_irq_disable();
		/* should have been called from irqsafe timer with irq already off */
		__queue_work(dwork->cpu, cwq->wq, &dwork->work);
		local_irq_enable();
		}
		EXPORT_SYMBOL_GPL(delayed_work_timer_fn);

		@@ -1444,7 +1446,7 @@ EXPORT_SYMBOL_GPL(queue_delayed_work);
		* Returns %false if @dwork was idle and queued, %true if @dwork was
		* pending and its timer was modified.
		*
		* This function is safe to call from any context other than IRQ handler.
		* This function is safe to call from any context including IRQ handler.
		* See try_to_grab_pending() for details.
		*/
		bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,

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