Re: [RFC PATCH 1/6] task_work: Provide means to check if a work is queued

[Oleg Nesterov <oleg@redhat.com>]

On 06/25, Frederic Weisbecker wrote:
>
> --- a/kernel/task_work.c
> +++ b/kernel/task_work.c
> @@ -177,6 +177,7 @@ void task_work_run(void)
>
>  		do {
>  			next = work->next;
> +			work->next = TASK_WORK_DEQUEUED;

OK, but then the additional change below makes sense too?

Oleg.
---

--- x/kernel/task_work.c
+++ x/kernel/task_work.c
@@ -106,8 +106,10 @@ task_work_cancel_match(struct task_struc
 		if (!match(work, data)) {
 			pprev = &work->next;
 			work = READ_ONCE(*pprev);
-		} else if (try_cmpxchg(pprev, &work, work->next))
+		} else if (try_cmpxchg(pprev, &work, work->next)) {
+			work->next = TASK_WORK_DEQUEUED;
 			break;
+		}
 	}
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);