Re: workqueue and pending

[Andrew Morton <akpm@osdl.org>]

Mikkel Christiansen <mixxel@cs.auc.dk> wrote:
>
> We're trying to use the workqueue interface for scheduling a delayed 
> gargage collector.
> Since we only need a single delayed thread we used the DECLEARE_WORK macro.
> 
> The problem is that once we call cancel_delayed_work we can't schedule 
> work again.

It looks like nobody has tried to do that yet.

> Having looked at the code i noticed that cancel_delayed_work only 
> deletes the timer but
> doesn't set clear the "pending" bit, thus any call to 
> schedule_delayed_work is ignorred.

Does this work?

--- 25/include/linux/workqueue.h~cancel_delayed_work-fix	Mon May  3 16:24:46 2004
+++ 25-akpm/include/linux/workqueue.h	Mon May  3 16:26:01 2004
@@ -7,6 +7,7 @@
 
 #include <linux/timer.h>
 #include <linux/linkage.h>
+#include <linux/bitops.h>
 
 struct workqueue_struct;
 
@@ -75,8 +76,11 @@ extern void init_workqueues(void);
  */
 static inline int cancel_delayed_work(struct work_struct *work)
 {
-	return del_timer_sync(&work->timer);
+	int ret;
+
+	ret = del_timer_sync(&work->timer);
+	clear_bit(0, &work->pending);
+	return ret;
 }
 
 #endif
-

_