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-rw-r--r--kernel/kthread.c102
1 files changed, 102 insertions, 0 deletions
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;