diff options
| -rw-r--r-- | include/linux/kthread.h | 4 | ||||
| -rw-r--r-- | kernel/kthread.c | 53 |
2 files changed, 57 insertions, 0 deletions
diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 77435dcde707..5c2ec2c4eb22 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -168,6 +168,10 @@ bool kthread_queue_delayed_work(struct kthread_worker *worker, struct kthread_delayed_work *dwork, unsigned long delay); +bool kthread_mod_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 20505c632bc3..c1fcc63fa605 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -976,6 +976,59 @@ static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork, return false; } +/** + * kthread_mod_delayed_work - modify delay of or queue a kthread delayed work + * @worker: kthread worker to use + * @dwork: kthread delayed work to queue + * @delay: number of jiffies to wait before queuing + * + * If @dwork is idle, equivalent to kthread_queue_delayed_work(). Otherwise, + * modify @dwork's timer so that it expires after @delay. If @delay is zero, + * @work is guaranteed to be queued immediately. + * + * Return: %true if @dwork was pending and its timer was modified, + * %false otherwise. + * + * A special case is when the work is being canceled in parallel. + * It might be caused either by the real kthread_cancel_delayed_work_sync() + * or yet another kthread_mod_delayed_work() call. We let the other command + * win and return %false here. The caller is supposed to synchronize these + * operations a reasonable way. + * + * This function is safe to call from any context including IRQ handler. + * See __kthread_cancel_work() and kthread_delayed_work_timer_fn() + * for details. + */ +bool kthread_mod_delayed_work(struct kthread_worker *worker, + struct kthread_delayed_work *dwork, + unsigned long delay) +{ + struct kthread_work *work = &dwork->work; + unsigned long flags; + int ret = false; + + spin_lock_irqsave(&worker->lock, flags); + + /* Do not bother with canceling when never queued. */ + if (!work->worker) + goto fast_queue; + + /* Work must not be used with >1 worker, see kthread_queue_work() */ + WARN_ON_ONCE(work->worker != worker); + + /* Do not fight with another command that is canceling this work. */ + if (work->canceling) + goto out; + + ret = __kthread_cancel_work(work, true, &flags); +fast_queue: + __kthread_queue_delayed_work(worker, dwork, delay); +out: + spin_unlock_irqrestore(&worker->lock, flags); + return ret; +} +EXPORT_SYMBOL_GPL(kthread_mod_delayed_work); + static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork) { struct kthread_worker *worker = work->worker; |