diff options
| -rw-r--r-- | kernel/workqueue.c | 70 |
1 files changed, 31 insertions, 39 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 1ea4bcb86974..b7bb37ab03bc 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -36,23 +36,13 @@ /* * The per-CPU workqueue (if single thread, we always use the first * possible cpu). - * - * The sequence counters are for flush_scheduled_work(). It wants to wait - * until all currently-scheduled works are completed, but it doesn't - * want to be livelocked by new, incoming ones. So it waits until - * remove_sequence is >= the insert_sequence which pertained when - * flush_scheduled_work() was called. */ struct cpu_workqueue_struct { spinlock_t lock; - long remove_sequence; /* Least-recently added (next to run) */ - long insert_sequence; /* Next to add */ - struct list_head worklist; wait_queue_head_t more_work; - wait_queue_head_t work_done; struct workqueue_struct *wq; struct task_struct *thread; @@ -138,8 +128,6 @@ static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work f(work); spin_lock_irqsave(&cwq->lock, flags); - cwq->remove_sequence++; - wake_up(&cwq->work_done); ret = 1; } spin_unlock_irqrestore(&cwq->lock, flags); @@ -187,7 +175,6 @@ static void __queue_work(struct cpu_workqueue_struct *cwq, spin_lock_irqsave(&cwq->lock, flags); set_wq_data(work, cwq); list_add_tail(&work->entry, &cwq->worklist); - cwq->insert_sequence++; wake_up(&cwq->more_work); spin_unlock_irqrestore(&cwq->lock, flags); } @@ -338,8 +325,6 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) } spin_lock_irqsave(&cwq->lock, flags); - cwq->remove_sequence++; - wake_up(&cwq->work_done); } cwq->run_depth--; spin_unlock_irqrestore(&cwq->lock, flags); @@ -394,6 +379,25 @@ static int worker_thread(void *__cwq) return 0; } +struct wq_barrier { + struct work_struct work; + struct completion done; +}; + +static void wq_barrier_func(struct work_struct *work) +{ + struct wq_barrier *barr = container_of(work, struct wq_barrier, work); + complete(&barr->done); +} + +static inline void init_wq_barrier(struct wq_barrier *barr) +{ + INIT_WORK(&barr->work, wq_barrier_func); + __set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work)); + + init_completion(&barr->done); +} + static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) { if (cwq->thread == current) { @@ -401,23 +405,18 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) * Probably keventd trying to flush its own queue. So simply run * it by hand rather than deadlocking. */ + mutex_unlock(&workqueue_mutex); run_workqueue(cwq); + mutex_lock(&workqueue_mutex); } else { - DEFINE_WAIT(wait); - long sequence_needed; + struct wq_barrier barr; - spin_lock_irq(&cwq->lock); - sequence_needed = cwq->insert_sequence; + init_wq_barrier(&barr); + __queue_work(cwq, &barr.work); - while (sequence_needed - cwq->remove_sequence > 0) { - prepare_to_wait(&cwq->work_done, &wait, - TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&cwq->lock); - schedule(); - spin_lock_irq(&cwq->lock); - } - finish_wait(&cwq->work_done, &wait); - spin_unlock_irq(&cwq->lock); + mutex_unlock(&workqueue_mutex); + wait_for_completion(&barr.done); + mutex_lock(&workqueue_mutex); } } @@ -428,29 +427,25 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) * Forces execution of the workqueue and blocks until its completion. * This is typically used in driver shutdown handlers. * - * This function will sample each workqueue's current insert_sequence number and - * will sleep until the head sequence is greater than or equal to that. This - * means that we sleep until all works which were queued on entry have been - * handled, but we are not livelocked by new incoming ones. + * We sleep until all works which were queued on entry have been handled, + * but we are not livelocked by new incoming ones. * * This function used to run the workqueues itself. Now we just wait for the * helper threads to do it. */ void fastcall flush_workqueue(struct workqueue_struct *wq) { - might_sleep(); - + mutex_lock(&workqueue_mutex); if (is_single_threaded(wq)) { /* Always use first cpu's area. */ flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); } else { int cpu; - mutex_lock(&workqueue_mutex); for_each_online_cpu(cpu) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); - mutex_unlock(&workqueue_mutex); } + mutex_unlock(&workqueue_mutex); } EXPORT_SYMBOL_GPL(flush_workqueue); @@ -463,12 +458,9 @@ static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, spin_lock_init(&cwq->lock); cwq->wq = wq; cwq->thread = NULL; - cwq->insert_sequence = 0; - cwq->remove_sequence = 0; cwq->freezeable = freezeable; INIT_LIST_HEAD(&cwq->worklist); init_waitqueue_head(&cwq->more_work); - init_waitqueue_head(&cwq->work_done); if (is_single_threaded(wq)) p = kthread_create(worker_thread, cwq, "%s", wq->name); |