CANCEL_WORK_SYNC(9) Driver Basics CANCEL_WORK_SYNC(9)
NAME cancel_work_sync - block until a work_struct´s callback has terminated
SYNOPSIS int cancel_work_sync(struct work_struct * work);
ARGUMENTS work the work which is to be flushed
DESCRIPTION Returns true if work was pending.
cancel_work_sync will cancel the work if it is queued. If the work´s callback appears to be running, cancel_work_sync will block until it has completed.
It is possible to use this function if the work re-queues itself. It can cancel the work even if it migrates to another workqueue, however in that case it only guarantees that work->func has completed on the last queued workqueue.
cancel_work_sync(delayed_work->work) should be used only if ->timer is not pending, otherwise it goes into a busy-wait loop until the timer expires.
The caller must ensure that workqueue_struct on which this work was last queued can´t be destroyed before this function returns.
COPYRIGHT Kernel Hackers Manual 2.6. July 2015 CANCEL_WORK_SYNC(9)