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>
This commit is contained in:
Tejun Heo 2013-03-12 17:41:37 -07:00
parent 226223ab3c
commit e626761691
2 changed files with 14 additions and 0 deletions

View File

@ -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);

View File

@ -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