From e62676169118bc2d42e5008b3f8872646313f077 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 12 Mar 2013 17:41:37 -0700 Subject: [PATCH] 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 --- include/linux/workqueue.h | 1 + kernel/workqueue.c | 13 +++++++++++++ 2 files changed, 14 insertions(+) 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); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c82feac0a878..f5c8bbb9ada3 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4071,6 +4071,19 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) } EXPORT_SYMBOL_GPL(workqueue_set_max_active); +/** + * current_is_workqueue_rescuer - is %current workqueue rescuer? + * + * Determine whether %current is a workqueue rescuer. Can be used from + * work functions to determine whether it's being run off the rescuer task. + */ +bool current_is_workqueue_rescuer(void) +{ + struct worker *worker = current_wq_worker(); + + return worker && worker == worker->current_pwq->wq->rescuer; +} + /** * workqueue_congested - test whether a workqueue is congested * @cpu: CPU in question -- 2.20.1