workqueue: implement current_is_workqueue_rescuer()

Implement a function which queries whether it currently is running off
a workqueue rescuer.  This will be used to convert writeback to
workqueue.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 7f6d29a417c0..df30763c8682 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -451,6 +451,7 @@ extern bool cancel_delayed_work_sync(struct delayed_work *dwork);
 
 extern void workqueue_set_max_active(struct workqueue_struct *wq,
                                      int max_active);
+extern bool current_is_workqueue_rescuer(void);
 extern bool workqueue_congested(int cpu, struct workqueue_struct *wq);
 extern unsigned int work_busy(struct work_struct *work);