2008-07-06 16:25:17

by Oleg Nesterov

Subject: [PATCH] workqueues: lockdep annotations for flush_work()

Add lockdep annotations to flush_work() and update the comment.

Signed-off-by: Oleg Nesterov <[email protected]>

--- 26-rc2/kernel/workqueue.c~FW_LOCKDEP 2008-06-29 19:36:27.000000000 +0400
+++ 26-rc2/kernel/workqueue.c 2008-07-06 20:15:16.000000000 +0400
@@ -403,6 +403,8 @@ EXPORT_SYMBOL_GPL(flush_workqueue);
* flush_work - block until a work_struct's callback has terminated
* @work: the work which is to be flushed
*
+ * Returns false if @work has already terminated.
+ *
* It is expected that, prior to calling flush_work(), the caller has
* arranged for the work to not be requeued, otherwise it doesn't make
* sense to use this function.
@@ -418,6 +420,9 @@ int flush_work(struct work_struct *work)
if (!cwq)
return 0;

+ lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+ lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+
prev = NULL;
spin_lock_irq(&cwq->lock);
if (!list_empty(&work->entry)) {

2008-07-06 17:50:26

by Jarek Poplawski

Subject: Re: [PATCH] workqueues: lockdep annotations for flush_work()

On Sun, Jul 06, 2008 at 08:28:00PM +0400, Oleg Nesterov wrote:
> Add lockdep annotations to flush_work() and update the comment.
>
> Signed-off-by: Oleg Nesterov <[email protected]>

Looks OK to me. (But probably the comment on "true" would be easier
(more precise).)

Regards,
Jarek P.

>
> --- 26-rc2/kernel/workqueue.c~FW_LOCKDEP 2008-06-29 19:36:27.000000000 +0400
> +++ 26-rc2/kernel/workqueue.c 2008-07-06 20:15:16.000000000 +0400
> @@ -403,6 +403,8 @@ EXPORT_SYMBOL_GPL(flush_workqueue);
> * flush_work - block until a work_struct's callback has terminated
> * @work: the work which is to be flushed
> *
> + * Returns false if @work has already terminated.
> + *
> * It is expected that, prior to calling flush_work(), the caller has
> * arranged for the work to not be requeued, otherwise it doesn't make
> * sense to use this function.
> @@ -418,6 +420,9 @@ int flush_work(struct work_struct *work)
> if (!cwq)
> return 0;
>
> + lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
> + lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
> +
> prev = NULL;
> spin_lock_irq(&cwq->lock);
> if (!list_empty(&work->entry)) {
>