The patch titled
workqueues: add kerneldoc for flush_scheduled_work()
has been added to the -mm tree. Its filename is
workqueues-add-kerneldoc-for-flush_scheduled_work.patch
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------------------------------------------------------
Subject: workqueues: add kerneldoc for flush_scheduled_work()
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
This patch (as1279) adds kerneldoc for flush_scheduled_work()
containing a stern warning that the function should be avoided.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff -puN kernel/workqueue.c~workqueues-add-kerneldoc-for-flush_scheduled_work kernel/workqueue.c
--- a/kernel/workqueue.c~workqueues-add-kerneldoc-for-flush_scheduled_work
+++ a/kernel/workqueue.c
@@ -689,6 +689,24 @@ int schedule_on_each_cpu(work_func_t fun
return 0;
}
+/**
+ * flush_scheduled_work - ensure that all work scheduled on keventd_wq has run to completion.
+ *
+ * Blocks until all works on the keventd_wq global workqueue have completed.
+ * We sleep until all works present upon entry have been handled, but we
+ * are not livelocked by new incoming ones.
+ *
+ * Use of this function is discouraged, as it is highly prone to deadlock.
+ * It should never be called from within a work routine on the global
+ * queue, and it should never be called while holding a mutex required
+ * by one of the works on the global queue. But the fact that keventd_wq
+ * _is_ global means that it can contain works requiring practically any
+ * mutex. Hence this routine shouldn't be called while holding any mutex.
+ *
+ * Consider using cancel_work_sync() or cancel_delayed_work_sync() instead.
+ * They don't do the same thing (they cancel the work instead of waiting
+ * for it to complete), but in most cases they will suffice.
+ */
void flush_scheduled_work(void)
{
flush_workqueue(keventd_wq);
_
Patches currently in -mm which might be from stern@xxxxxxxxxxxxxxxxxxx are
origin.patch
linux-next.patch
drivers-usb-gadget-s3c2410_udcc-fix.patch
workqueues-add-kerneldoc-for-flush_scheduled_work.patch
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