diff options
| -rw-r--r-- | include/linux/kthread.h | 33 | ||||
| -rw-r--r-- | kernel/kthread.c | 102 |
2 files changed, 135 insertions, 0 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index afc8939da861..4acde1ae2228 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -63,10 +63,12 @@ extern int tsk_fork_get_node(struct task_struct *tsk); */ struct kthread_work; typedef void (*kthread_work_func_t)(struct kthread_work *work); +void kthread_delayed_work_timer_fn(unsigned long __data); struct kthread_worker { spinlock_t lock; struct list_head work_list; + struct list_head delayed_work_list; struct task_struct *task; struct kthread_work *current_work; }; @@ -77,9 +79,15 @@ struct kthread_work { struct kthread_worker *worker; }; +struct kthread_delayed_work { + struct kthread_work work; + struct timer_list timer; +}; + #define KTHREAD_WORKER_INIT(worker) { \ .lock = __SPIN_LOCK_UNLOCKED((worker).lock), \ .work_list = LIST_HEAD_INIT((worker).work_list), \ + .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\ } #define KTHREAD_WORK_INIT(work, fn) { \ @@ -87,12 +95,23 @@ struct kthread_work { .func = (fn), \ } +#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \ + .work = KTHREAD_WORK_INIT((dwork).work, (fn)), \ + .timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn, \ + 0, (unsigned long)&(dwork), \ + TIMER_IRQSAFE), \ + } + #define DEFINE_KTHREAD_WORKER(worker) \ struct kthread_worker worker = KTHREAD_WORKER_INIT(worker) #define DEFINE_KTHREAD_WORK(work, fn) \ struct kthread_work work = KTHREAD_WORK_INIT(work, fn) +#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \ + struct kthread_delayed_work dwork = \ + KTHREAD_DELAYED_WORK_INIT(dwork, fn) + /* * kthread_worker.lock needs its own lockdep class key when defined on * stack with lockdep enabled. Use the following macros in such cases. @@ -122,6 +141,15 @@ extern void __kthread_init_worker(struct kthread_worker *worker, (work)->func = (fn); \ } while (0) +#define kthread_init_delayed_work(dwork, fn) \ + do { \ + kthread_init_work(&(dwork)->work, (fn)); \ + __setup_timer(&(dwork)->timer, \ + kthread_delayed_work_timer_fn, \ + (unsigned long)(dwork), \ + TIMER_IRQSAFE); \ + } while (0) + int kthread_worker_fn(void *worker_ptr); __printf(1, 2) @@ -133,6 +161,11 @@ kthread_create_worker_on_cpu(int cpu, const char namefmt[], ...); bool kthread_queue_work(struct kthread_worker *worker, struct kthread_work *work); + +bool kthread_queue_delayed_work(struct kthread_worker *worker, + struct kthread_delayed_work *dwork, + unsigned long delay); + void kthread_flush_work(struct kthread_work *work); void kthread_flush_worker(struct kthread_worker *worker); diff --git a/kernel/kthread.c b/kernel/kthread.c index 524dfc8247d7..a5c6d709349d 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -563,6 +563,7 @@ void __kthread_init_worker(struct kthread_worker *worker, spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); + INIT_LIST_HEAD(&worker->delayed_work_list); worker->task = NULL; } EXPORT_SYMBOL_GPL(__kthread_init_worker); @@ -767,6 +768,107 @@ bool kthread_queue_work(struct kthread_worker *worker, } EXPORT_SYMBOL_GPL(kthread_queue_work); +/** + * kthread_delayed_work_timer_fn - callback that queues the associated kthread + * delayed work when the timer expires. + * @__data: pointer to the data associated with the timer + * + * The format of the function is defined by struct timer_list. + * It should have been called from irqsafe timer with irq already off. + */ +void kthread_delayed_work_timer_fn(unsigned long __data) +{ + struct kthread_delayed_work *dwork = + (struct kthread_delayed_work *)__data; + struct kthread_work *work = &dwork->work; + struct kthread_worker *worker = work->worker; + + /* + * This might happen when a pending work is reinitialized. + * It means that it is used a wrong way. + */ + if (WARN_ON_ONCE(!worker)) + return; + + spin_lock(&worker->lock); + /* Work must not be used with >1 worker, see kthread_queue_work(). */ + WARN_ON_ONCE(work->worker != worker); + + /* Move the work from worker->delayed_work_list. */ + WARN_ON_ONCE(list_empty(&work->node)); + list_del_init(&work->node); + kthread_insert_work(worker, work, &worker->work_list); + + spin_unlock(&worker->lock); +} +EXPORT_SYMBOL(kthread_delayed_work_timer_fn); + +void __kthread_queue_delayed_work(struct kthread_worker *worker, + struct kthread_delayed_work *dwork, + unsigned long delay) +{ + struct timer_list *timer = &dwork->timer; + struct kthread_work *work = &dwork->work; + + WARN_ON_ONCE(timer->function != kthread_delayed_work_timer_fn || + timer->data != (unsigned long)dwork); + + /* + * If @delay is 0, queue @dwork->work immediately. This is for + * both optimization and correctness. The earliest @timer can + * expire is on the closest next tick and delayed_work users depend + * on that there's no such delay when @delay is 0. + */ + if (!delay) { + kthread_insert_work(worker, work, &worker->work_list); + return; + } + + /* Be paranoid and try to detect possible races already now. */ + kthread_insert_work_sanity_check(worker, work); + + list_add(&work->node, &worker->delayed_work_list); + work->worker = worker; + timer_stats_timer_set_start_info(&dwork->timer); + timer->expires = jiffies + delay; + add_timer(timer); +} + +/** + * kthread_queue_delayed_work - queue the associated kthread work + * after a delay. + * @worker: target kthread_worker + * @dwork: kthread_delayed_work to queue + * @delay: number of jiffies to wait before queuing + * + * If the work has not been pending it starts a timer that will queue + * the work after the given @delay. If @delay is zero, it queues the + * work immediately. + * + * Return: %false if the @work has already been pending. It means that + * either the timer was running or the work was queued. It returns %true + * otherwise. + */ +bool kthread_queue_delayed_work(struct kthread_worker *worker, + struct kthread_delayed_work *dwork, + unsigned long delay) +{ + struct kthread_work *work = &dwork->work; + unsigned long flags; + bool ret = false; + + spin_lock_irqsave(&worker->lock, flags); + + if (list_empty(&work->node)) { + __kthread_queue_delayed_work(worker, dwork, delay); + ret = true; + } + + spin_unlock_irqrestore(&worker->lock, flags); + return ret; +} +EXPORT_SYMBOL_GPL(kthread_queue_delayed_work); + struct kthread_flush_work { struct kthread_work work; struct completion done; |