workqueue: rename kernel/workqueue_sched.h to kernel/workqueue_internal.h

Workqueue wants to expose more interface internal to kernel/.  Instead
of adding a new header file, repurpose kernel/workqueue_sched.h.
Rename it to workqueue_internal.h and add include protector.

This patch doesn't introduce any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>

kernel/sched/core.c

@@ -83,7 +83,7 @@
 #endif
 
 #include "sched.h"
-#include "../workqueue_sched.h"
+#include "../workqueue_internal.h"
 #include "../smpboot.h"
 
 #define CREATE_TRACE_POINTS

kernel/workqueue.c

@@ -43,7 +43,7 @@
 #include <linux/idr.h>
 #include <linux/hashtable.h>
 
-#include "workqueue_sched.h"
+#include "workqueue_internal.h"
 
 enum {
 	/*

kernel/workqueue_sched.h → kernel/workqueue_internal.h

 /*
- * kernel/workqueue_sched.h
+ * kernel/workqueue_internal.h
  *
- * Scheduler hooks for concurrency managed workqueue.  Only to be
- * included from sched.c and workqueue.c.
+ * Workqueue internal header file.  Only to be included by workqueue and
+ * core kernel subsystems.
+ */
+#ifndef _KERNEL_WORKQUEUE_INTERNAL_H
+#define _KERNEL_WORKQUEUE_INTERNAL_H
+
+/*
+ * Scheduler hooks for concurrency managed workqueue.  Only to be used from
+ * sched.c and workqueue.c.
  */
 void wq_worker_waking_up(struct task_struct *task, unsigned int cpu);
 struct task_struct *wq_worker_sleeping(struct task_struct *task,
 				       unsigned int cpu);
+
+#endif /* _KERNEL_WORKQUEUE_INTERNAL_H */