workqueue: add system_freezeable_wq

Add system wide freezeable workqueue.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 1ac1158..de6a755 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -286,11 +286,15 @@
  * any specific CPU, not concurrency managed, and all queued works are
  * executed immediately as long as max_active limit is not reached and
  * resources are available.
+ *
+ * system_freezeable_wq is equivalent to system_wq except that it's
+ * freezeable.
  */
 extern struct workqueue_struct *system_wq;
 extern struct workqueue_struct *system_long_wq;
 extern struct workqueue_struct *system_nrt_wq;
 extern struct workqueue_struct *system_unbound_wq;
+extern struct workqueue_struct *system_freezeable_wq;
 
 extern struct workqueue_struct *
 __alloc_workqueue_key(const char *name, unsigned int flags, int max_active,