workqueue: implement current_is_async()

This function queries whether %current is an async worker executing an
async item.  This will be used to implement warning on synchronous
request_module() from async workers.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 02549fa04587..cc35e7e62091 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -8,6 +8,7 @@
 #define _KERNEL_WORKQUEUE_INTERNAL_H
 
 #include <linux/workqueue.h>
+#include <linux/kthread.h>
 
 struct global_cwq;
 struct worker_pool;
@@ -44,6 +45,16 @@ struct worker {
         struct workqueue_struct *rescue_wq;     /* I: the workqueue to rescue */
 };
 
+/**
+ * current_wq_worker - return struct worker if %current is a workqueue worker
+ */
+static inline struct worker *current_wq_worker(void)
+{
+        if (current->flags & PF_WQ_WORKER)
+                return kthread_data(current);
+        return NULL;
+}
+
 /*
  * Scheduler hooks for concurrency managed workqueue.  Only to be used from
  * sched.c and workqueue.c.