Commit eef6a7d5 authored by Alan Stern's avatar Alan Stern Committed by Tejun Heo
Browse files

workqueue: warn about flush_scheduled_work() 



This patch (as1319) adds kerneldoc and a pointed warning to
flush_scheduled_work().

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 47dd5be2

kernel/workqueue.c

+24 −0
Original line number Diff line number Diff line
@@ -845,6 +845,30 @@ int schedule_on_each_cpu(work_func_t func) 
	return 0;

}



/**

 * flush_scheduled_work - ensure that any scheduled work has run to completion.

 *

 * Forces execution of the kernel-global workqueue and blocks until its

 * completion.

 *

 * Think twice before calling this function!  It's very easy to get into

 * trouble if you don't take great care.  Either of the following situations

 * will lead to deadlock:

 *

 *	One of the work items currently on the workqueue needs to acquire

 *	a lock held by your code or its caller.

 *

 *	Your code is running in the context of a work routine.

 *

 * They will be detected by lockdep when they occur, but the first might not

 * occur very often.  It depends on what work items are on the workqueue and

 * what locks they need, which you have no control over.

 *

 * In most situations flushing the entire workqueue is overkill; you merely

 * need to know that a particular work item isn't queued and isn't running.

 * In such cases you should use cancel_delayed_work_sync() or

 * cancel_work_sync() instead.

 */

void flush_scheduled_work(void)

{

	flush_workqueue(keventd_wq);