From 606a5020b9bdceb20b4f43e11db0054afa349028 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 20 Aug 2012 14:51:23 -0700 Subject: [PATCH] workqueue: gut flush[_delayed]_work_sync() Now that all workqueues are non-reentrant, flush[_delayed]_work_sync() are equivalent to flush[_delayed]_work(). Drop the separate implementation and make them thin wrappers around flush[_delayed]_work(). * start_flush_work() no longer takes @wait_executing as the only left user - flush_work() - always sets it to %true. * __cancel_work_timer() uses flush_work() instead of wait_on_work(). Signed-off-by: Tejun Heo --- include/linux/workqueue.h | 14 ++++- kernel/workqueue.c | 122 ++++---------------------------------- 2 files changed, 22 insertions(+), 114 deletions(-) diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index b14d5d59af7c..4f9d3bc161a2 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -412,11 +412,9 @@ extern int keventd_up(void); int execute_in_process_context(work_func_t fn, struct execute_work *); extern bool flush_work(struct work_struct *work); -extern bool flush_work_sync(struct work_struct *work); extern bool cancel_work_sync(struct work_struct *work); extern bool flush_delayed_work(struct delayed_work *dwork); -extern bool flush_delayed_work_sync(struct delayed_work *work); extern bool cancel_delayed_work_sync(struct delayed_work *dwork); extern void workqueue_set_max_active(struct workqueue_struct *wq, @@ -456,6 +454,18 @@ static inline bool __cancel_delayed_work(struct delayed_work *work) return ret; } +/* used to be different but now identical to flush_work(), deprecated */ +static inline bool flush_work_sync(struct work_struct *work) +{ + return flush_work(work); +} + +/* used to be different but now identical to flush_delayed_work(), deprecated */ +static inline bool flush_delayed_work_sync(struct delayed_work *dwork) +{ + return flush_delayed_work(dwork); +} + #ifndef CONFIG_SMP static inline long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg) { diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c4feef9798ea..5f13a9a2c792 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2801,8 +2801,7 @@ reflush: } EXPORT_SYMBOL_GPL(drain_workqueue); -static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, - bool wait_executing) +static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr) { struct worker *worker = NULL; struct global_cwq *gcwq; @@ -2824,13 +2823,12 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr, cwq = get_work_cwq(work); if (unlikely(!cwq || gcwq != cwq->pool->gcwq)) goto already_gone; - } else if (wait_executing) { + } else { worker = find_worker_executing_work(gcwq, work); if (!worker) goto already_gone; cwq = worker->current_cwq; - } else - goto already_gone; + } insert_wq_barrier(cwq, barr, work, worker); spin_unlock_irq(&gcwq->lock); @@ -2857,15 +2855,8 @@ already_gone: * flush_work - wait for a work to finish executing the last queueing instance * @work: the work to flush * - * Wait until @work has finished execution. This function considers - * only the last queueing instance of @work. If @work has been - * enqueued across different CPUs on a non-reentrant workqueue or on - * multiple workqueues, @work might still be executing on return on - * some of the CPUs from earlier queueing. - * - * If @work was queued only on a non-reentrant, ordered or unbound - * workqueue, @work is guaranteed to be idle on return if it hasn't - * been requeued since flush started. + * Wait until @work has finished execution. @work is guaranteed to be idle + * on return if it hasn't been requeued since flush started. * * RETURNS: * %true if flush_work() waited for the work to finish execution, @@ -2878,85 +2869,15 @@ bool flush_work(struct work_struct *work) lock_map_acquire(&work->lockdep_map); lock_map_release(&work->lockdep_map); - if (start_flush_work(work, &barr, true)) { + if (start_flush_work(work, &barr)) { wait_for_completion(&barr.done); destroy_work_on_stack(&barr.work); return true; - } else - return false; -} -EXPORT_SYMBOL_GPL(flush_work); - -static bool wait_on_cpu_work(struct global_cwq *gcwq, struct work_struct *work) -{ - struct wq_barrier barr; - struct worker *worker; - - spin_lock_irq(&gcwq->lock); - - worker = find_worker_executing_work(gcwq, work); - if (unlikely(worker)) - insert_wq_barrier(worker->current_cwq, &barr, work, worker); - - spin_unlock_irq(&gcwq->lock); - - if (unlikely(worker)) { - wait_for_completion(&barr.done); - destroy_work_on_stack(&barr.work); - return true; - } else + } else { return false; -} - -static bool wait_on_work(struct work_struct *work) -{ - bool ret = false; - int cpu; - - might_sleep(); - - lock_map_acquire(&work->lockdep_map); - lock_map_release(&work->lockdep_map); - - for_each_gcwq_cpu(cpu) - ret |= wait_on_cpu_work(get_gcwq(cpu), work); - return ret; -} - -/** - * flush_work_sync - wait until a work has finished execution - * @work: the work to flush - * - * Wait until @work has finished execution. On return, it's - * guaranteed that all queueing instances of @work which happened - * before this function is called are finished. In other words, if - * @work hasn't been requeued since this function was called, @work is - * guaranteed to be idle on return. - * - * RETURNS: - * %true if flush_work_sync() waited for the work to finish execution, - * %false if it was already idle. - */ -bool flush_work_sync(struct work_struct *work) -{ - struct wq_barrier barr; - bool pending, waited; - - /* we'll wait for executions separately, queue barr only if pending */ - pending = start_flush_work(work, &barr, false); - - /* wait for executions to finish */ - waited = wait_on_work(work); - - /* wait for the pending one */ - if (pending) { - wait_for_completion(&barr.done); - destroy_work_on_stack(&barr.work); } - - return pending || waited; } -EXPORT_SYMBOL_GPL(flush_work_sync); +EXPORT_SYMBOL_GPL(flush_work); static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) { @@ -2970,14 +2891,14 @@ static bool __cancel_work_timer(struct work_struct *work, bool is_dwork) * would be waiting for before retrying. */ if (unlikely(ret == -ENOENT)) - wait_on_work(work); + flush_work(work); } while (unlikely(ret < 0)); /* tell other tasks trying to grab @work to back off */ mark_work_canceling(work); local_irq_restore(flags); - wait_on_work(work); + flush_work(work); clear_work_data(work); return ret; } @@ -3029,29 +2950,6 @@ bool flush_delayed_work(struct delayed_work *dwork) } EXPORT_SYMBOL(flush_delayed_work); -/** - * flush_delayed_work_sync - wait for a dwork to finish - * @dwork: the delayed work to flush - * - * Delayed timer is cancelled and the pending work is queued for - * execution immediately. Other than timer handling, its behavior - * is identical to flush_work_sync(). - * - * RETURNS: - * %true if flush_work_sync() waited for the work to finish execution, - * %false if it was already idle. - */ -bool flush_delayed_work_sync(struct delayed_work *dwork) -{ - local_irq_disable(); - if (del_timer_sync(&dwork->timer)) - __queue_work(dwork->cpu, - get_work_cwq(&dwork->work)->wq, &dwork->work); - local_irq_enable(); - return flush_work_sync(&dwork->work); -} -EXPORT_SYMBOL(flush_delayed_work_sync); - /** * cancel_delayed_work_sync - cancel a delayed work and wait for it to finish * @dwork: the delayed work cancel -- 2.39.5