diff options
| -rw-r--r-- | include/linux/workqueue.h | 4 | ||||
| -rw-r--r-- | kernel/workqueue.c | 95 |
2 files changed, 95 insertions, 4 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index f16ba1e0687d..26a70992dec8 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -178,6 +178,8 @@ extern int FASTCALL(queue_delayed_work(struct workqueue_struct *wq, struct delay extern int queue_delayed_work_on(int cpu, struct workqueue_struct *wq, struct delayed_work *work, unsigned long delay); extern void FASTCALL(flush_workqueue(struct workqueue_struct *wq)); +extern void flush_work(struct workqueue_struct *wq, struct work_struct *work); +extern void flush_work_keventd(struct work_struct *work); extern int FASTCALL(schedule_work(struct work_struct *work)); extern int FASTCALL(run_scheduled_work(struct work_struct *work)); @@ -199,7 +201,7 @@ int execute_in_process_context(work_func_t fn, struct execute_work *); * Kill off a pending schedule_delayed_work(). Note that the work callback * function may still be running on return from cancel_delayed_work(), unless * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or - * cancel_work_sync() to wait on it. + * flush_work() or cancel_work_sync() to wait on it. */ static inline int cancel_delayed_work(struct delayed_work *work) { diff --git a/kernel/workqueue.c b/kernel/workqueue.c index b7bb37ab03bc..918d55267a12 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -46,6 +46,7 @@ struct cpu_workqueue_struct { struct workqueue_struct *wq; struct task_struct *thread; + struct work_struct *current_work; int run_depth; /* Detect run_workqueue() recursion depth */ @@ -120,6 +121,7 @@ static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work && work_pending(work) && !list_empty(&work->entry)) { work_func_t f = work->func; + cwq->current_work = work; list_del_init(&work->entry); spin_unlock_irqrestore(&cwq->lock, flags); @@ -128,6 +130,7 @@ static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work f(work); spin_lock_irqsave(&cwq->lock, flags); + cwq->current_work = NULL; ret = 1; } spin_unlock_irqrestore(&cwq->lock, flags); @@ -166,6 +169,17 @@ int fastcall run_scheduled_work(struct work_struct *work) } EXPORT_SYMBOL(run_scheduled_work); +static void insert_work(struct cpu_workqueue_struct *cwq, + struct work_struct *work, int tail) +{ + set_wq_data(work, cwq); + if (tail) + list_add_tail(&work->entry, &cwq->worklist); + else + list_add(&work->entry, &cwq->worklist); + wake_up(&cwq->more_work); +} + /* Preempt must be disabled. */ static void __queue_work(struct cpu_workqueue_struct *cwq, struct work_struct *work) @@ -173,9 +187,7 @@ static void __queue_work(struct cpu_workqueue_struct *cwq, unsigned long flags; spin_lock_irqsave(&cwq->lock, flags); - set_wq_data(work, cwq); - list_add_tail(&work->entry, &cwq->worklist); - wake_up(&cwq->more_work); + insert_work(cwq, work, 1); spin_unlock_irqrestore(&cwq->lock, flags); } @@ -305,6 +317,7 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) struct work_struct, entry); work_func_t f = work->func; + cwq->current_work = work; list_del_init(cwq->worklist.next); spin_unlock_irqrestore(&cwq->lock, flags); @@ -325,6 +338,7 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq) } spin_lock_irqsave(&cwq->lock, flags); + cwq->current_work = NULL; } cwq->run_depth--; spin_unlock_irqrestore(&cwq->lock, flags); @@ -449,6 +463,75 @@ void fastcall flush_workqueue(struct workqueue_struct *wq) } EXPORT_SYMBOL_GPL(flush_workqueue); +static void wait_on_work(struct cpu_workqueue_struct *cwq, + struct work_struct *work) +{ + struct wq_barrier barr; + int running = 0; + + spin_lock_irq(&cwq->lock); + if (unlikely(cwq->current_work == work)) { + init_wq_barrier(&barr); + insert_work(cwq, &barr.work, 0); + running = 1; + } + spin_unlock_irq(&cwq->lock); + + if (unlikely(running)) { + mutex_unlock(&workqueue_mutex); + wait_for_completion(&barr.done); + mutex_lock(&workqueue_mutex); + } +} + +/** + * flush_work - block until a work_struct's callback has terminated + * @wq: the workqueue on which the work is queued + * @work: the work which is to be flushed + * + * flush_work() will attempt to cancel the work if it is queued. If the work's + * callback appears to be running, flush_work() will block until it has + * completed. + * + * flush_work() is designed to be used when the caller is tearing down data + * structures which the callback function operates upon. It is expected that, + * prior to calling flush_work(), the caller has arranged for the work to not + * be requeued. + */ +void flush_work(struct workqueue_struct *wq, struct work_struct *work) +{ + struct cpu_workqueue_struct *cwq; + + mutex_lock(&workqueue_mutex); + cwq = get_wq_data(work); + /* Was it ever queued ? */ + if (!cwq) + goto out; + + /* + * This work can't be re-queued, and the lock above protects us + * from take_over_work(), no need to re-check that get_wq_data() + * is still the same when we take cwq->lock. + */ + spin_lock_irq(&cwq->lock); + list_del_init(&work->entry); + work_release(work); + spin_unlock_irq(&cwq->lock); + + if (is_single_threaded(wq)) { + /* Always use first cpu's area. */ + wait_on_work(per_cpu_ptr(wq->cpu_wq, singlethread_cpu), work); + } else { + int cpu; + + for_each_online_cpu(cpu) + wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work); + } +out: + mutex_unlock(&workqueue_mutex); +} +EXPORT_SYMBOL_GPL(flush_work); + static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, int cpu, int freezeable) { @@ -650,6 +733,12 @@ void flush_scheduled_work(void) } EXPORT_SYMBOL(flush_scheduled_work); +void flush_work_keventd(struct work_struct *work) +{ + flush_work(keventd_wq, work); +} +EXPORT_SYMBOL(flush_work_keventd); + /** * cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work. * @wq: the controlling workqueue structure |