workqueue: cancel_delayed_work() should return %false if work item is idle

57b30ae77b ("workqueue: reimplement cancel_delayed_work() using
try_to_grab_pending()") made cancel_delayed_work() always return %true
unless someone else is also trying to cancel the work item, which is
broken - if the target work item is idle, the return value should be
%false.

try_to_grab_pending() indicates that the target work item was idle by
zero return value.  Use it for return.  Note that this brings
cancel_delayed_work() in line with __cancel_work_timer() in return
value handling.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <444a6439-b1a4-4740-9e7e-bc37267cfe73@default>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d951daa..042d221 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2982,7 +2982,7 @@ bool cancel_delayed_work(struct delayed_work *dwork)
 
        set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
        local_irq_restore(flags);
-       return true;
+       return ret;
 }
 EXPORT_SYMBOL(cancel_delayed_work);