workqueue: cleanup flush/cancel functions
Make the following cleanup changes. * Relocate flush/cancel function prototypes and definitions. * Relocate wait_on_cpu_work() and wait_on_work() before try_to_grab_pending(). These will be used to implement flush_work_sync(). * Make all flush/cancel functions return bool instead of int. * Update wait_on_cpu_work() and wait_on_work() to return %true if they actually waited. * Add / update comments. This patch doesn't cause any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo
Родитель
81dcaf6516
Коммит
401a8d048e
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@ -343,7 +343,6 @@ extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
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extern void flush_workqueue(struct workqueue_struct *wq);
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extern void flush_scheduled_work(void);
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extern void flush_delayed_work(struct delayed_work *work);
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extern int schedule_work(struct work_struct *work);
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extern int schedule_work_on(int cpu, struct work_struct *work);
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@ -355,8 +354,11 @@ extern int keventd_up(void);
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int execute_in_process_context(work_func_t fn, struct execute_work *);
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extern int flush_work(struct work_struct *work);
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extern int cancel_work_sync(struct work_struct *work);
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extern bool flush_work(struct work_struct *work);
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extern bool cancel_work_sync(struct work_struct *work);
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extern bool flush_delayed_work(struct delayed_work *dwork);
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extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
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extern void workqueue_set_max_active(struct workqueue_struct *wq,
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int max_active);
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@ -370,9 +372,9 @@ extern unsigned int work_busy(struct work_struct *work);
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* it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
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* cancel_work_sync() to wait on it.
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*/
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static inline int cancel_delayed_work(struct delayed_work *work)
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static inline bool cancel_delayed_work(struct delayed_work *work)
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{
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int ret;
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bool ret;
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ret = del_timer_sync(&work->timer);
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if (ret)
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@ -385,9 +387,9 @@ static inline int cancel_delayed_work(struct delayed_work *work)
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* if it returns 0 the timer function may be running and the queueing is in
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* progress.
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*/
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static inline int __cancel_delayed_work(struct delayed_work *work)
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static inline bool __cancel_delayed_work(struct delayed_work *work)
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{
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int ret;
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bool ret;
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ret = del_timer(&work->timer);
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if (ret)
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@ -395,8 +397,6 @@ static inline int __cancel_delayed_work(struct delayed_work *work)
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return ret;
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}
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extern int cancel_delayed_work_sync(struct delayed_work *work);
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/* Obsolete. use cancel_delayed_work_sync() */
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static inline
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void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq,
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@ -2327,16 +2327,24 @@ out_unlock:
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EXPORT_SYMBOL_GPL(flush_workqueue);
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/**
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* flush_work - block until a work_struct's callback has terminated
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* @work: the work which is to be flushed
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* flush_work - wait for a work to finish executing the last queueing instance
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* @work: the work to flush
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*
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* Returns false if @work has already terminated.
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* Wait until @work has finished execution. This function considers
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* only the last queueing instance of @work. If @work has been
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* enqueued across different CPUs on a non-reentrant workqueue or on
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* multiple workqueues, @work might still be executing on return on
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* some of the CPUs from earlier queueing.
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*
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* It is expected that, prior to calling flush_work(), the caller has
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* arranged for the work to not be requeued, otherwise it doesn't make
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* sense to use this function.
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* If @work was queued only on a non-reentrant, ordered or unbound
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* workqueue, @work is guaranteed to be idle on return if it hasn't
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* been requeued since flush started.
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*
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* RETURNS:
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* %true if flush_work() waited for the work to finish execution,
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* %false if it was already idle.
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*/
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int flush_work(struct work_struct *work)
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bool flush_work(struct work_struct *work)
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{
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struct worker *worker = NULL;
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struct global_cwq *gcwq;
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@ -2374,13 +2382,49 @@ int flush_work(struct work_struct *work)
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wait_for_completion(&barr.done);
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destroy_work_on_stack(&barr.work);
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return 1;
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return true;
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already_gone:
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spin_unlock_irq(&gcwq->lock);
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return 0;
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return false;
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}
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EXPORT_SYMBOL_GPL(flush_work);
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static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work)
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{
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struct wq_barrier barr;
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struct worker *worker;
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spin_lock_irq(&gcwq->lock);
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worker = find_worker_executing_work(gcwq, work);
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if (unlikely(worker))
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insert_wq_barrier(worker->current_cwq, &barr, work, worker);
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spin_unlock_irq(&gcwq->lock);
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if (unlikely(worker)) {
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wait_for_completion(&barr.done);
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destroy_work_on_stack(&barr.work);
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return true;
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} else
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return false;
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}
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static bool wait_on_work(struct work_struct *work)
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{
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bool ret = false;
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int cpu;
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might_sleep();
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lock_map_acquire(&work->lockdep_map);
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lock_map_release(&work->lockdep_map);
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for_each_gcwq_cpu(cpu)
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ret |= wait_on_cpu_work(get_gcwq(cpu), work);
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return ret;
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}
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/*
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* Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
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* so this work can't be re-armed in any way.
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@ -2423,39 +2467,7 @@ static int try_to_grab_pending(struct work_struct *work)
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return ret;
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}
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static void wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work)
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{
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struct wq_barrier barr;
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struct worker *worker;
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spin_lock_irq(&gcwq->lock);
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worker = find_worker_executing_work(gcwq, work);
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if (unlikely(worker))
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insert_wq_barrier(worker->current_cwq, &barr, work, worker);
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spin_unlock_irq(&gcwq->lock);
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if (unlikely(worker)) {
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wait_for_completion(&barr.done);
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destroy_work_on_stack(&barr.work);
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}
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}
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static void wait_on_work(struct work_struct *work)
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{
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int cpu;
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might_sleep();
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lock_map_acquire(&work->lockdep_map);
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lock_map_release(&work->lockdep_map);
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for_each_gcwq_cpu(cpu)
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wait_on_cpu_work(get_gcwq(cpu), work);
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}
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static int __cancel_work_timer(struct work_struct *work,
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static bool __cancel_work_timer(struct work_struct *work,
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struct timer_list* timer)
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{
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int ret;
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@ -2472,42 +2484,60 @@ static int __cancel_work_timer(struct work_struct *work,
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}
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/**
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* cancel_work_sync - block until a work_struct's callback has terminated
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* @work: the work which is to be flushed
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* cancel_work_sync - cancel a work and wait for it to finish
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* @work: the work to cancel
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*
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* Returns true if @work was pending.
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* Cancel @work and wait for its execution to finish. This function
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* can be used even if the work re-queues itself or migrates to
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* another workqueue. On return from this function, @work is
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* guaranteed to be not pending or executing on any CPU.
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*
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* cancel_work_sync() will cancel the work if it is queued. If the work's
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* callback appears to be running, cancel_work_sync() will block until it
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* has completed.
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* cancel_work_sync(&delayed_work->work) must not be used for
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* delayed_work's. Use cancel_delayed_work_sync() instead.
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*
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* It is possible to use this function if the work re-queues itself. It can
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* cancel the work even if it migrates to another workqueue, however in that
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* case it only guarantees that work->func() has completed on the last queued
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* workqueue.
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*
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* cancel_work_sync(&delayed_work->work) should be used only if ->timer is not
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* pending, otherwise it goes into a busy-wait loop until the timer expires.
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*
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* The caller must ensure that workqueue_struct on which this work was last
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* The caller must ensure that the workqueue on which @work was last
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* queued can't be destroyed before this function returns.
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*
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* RETURNS:
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* %true if @work was pending, %false otherwise.
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*/
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int cancel_work_sync(struct work_struct *work)
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bool cancel_work_sync(struct work_struct *work)
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{
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return __cancel_work_timer(work, NULL);
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}
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EXPORT_SYMBOL_GPL(cancel_work_sync);
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/**
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* cancel_delayed_work_sync - reliably kill off a delayed work.
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* @dwork: the delayed work struct
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* flush_delayed_work - wait for a dwork to finish executing the last queueing
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* @dwork: the delayed work to flush
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*
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* Returns true if @dwork was pending.
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* Delayed timer is cancelled and the pending work is queued for
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* immediate execution. Like flush_work(), this function only
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* considers the last queueing instance of @dwork.
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*
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* It is possible to use this function if @dwork rearms itself via queue_work()
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* or queue_delayed_work(). See also the comment for cancel_work_sync().
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* RETURNS:
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* %true if flush_work() waited for the work to finish execution,
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* %false if it was already idle.
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*/
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int cancel_delayed_work_sync(struct delayed_work *dwork)
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bool flush_delayed_work(struct delayed_work *dwork)
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{
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if (del_timer_sync(&dwork->timer))
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__queue_work(raw_smp_processor_id(),
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get_work_cwq(&dwork->work)->wq, &dwork->work);
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return flush_work(&dwork->work);
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}
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EXPORT_SYMBOL(flush_delayed_work);
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/**
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* cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
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* @dwork: the delayed work cancel
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*
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* This is cancel_work_sync() for delayed works.
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*
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* RETURNS:
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* %true if @dwork was pending, %false otherwise.
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*/
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bool cancel_delayed_work_sync(struct delayed_work *dwork)
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{
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return __cancel_work_timer(&dwork->work, &dwork->timer);
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}
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@ -2558,23 +2588,6 @@ int schedule_delayed_work(struct delayed_work *dwork,
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}
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EXPORT_SYMBOL(schedule_delayed_work);
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/**
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* flush_delayed_work - block until a dwork_struct's callback has terminated
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* @dwork: the delayed work which is to be flushed
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*
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* Any timeout is cancelled, and any pending work is run immediately.
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*/
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void flush_delayed_work(struct delayed_work *dwork)
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{
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if (del_timer_sync(&dwork->timer)) {
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__queue_work(get_cpu(), get_work_cwq(&dwork->work)->wq,
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&dwork->work);
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put_cpu();
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}
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flush_work(&dwork->work);
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}
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EXPORT_SYMBOL(flush_delayed_work);
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/**
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* schedule_delayed_work_on - queue work in global workqueue on CPU after delay
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* @cpu: cpu to use
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