sched/headers: Prepare for new header dependencies before moving code to <linux/sched/wake_q.h>

We are going to split <linux/sched/wake_q.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/wake_q.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched/wake_q.h

+#ifndef _LINUX_SCHED_WAKE_Q_H
+#define _LINUX_SCHED_WAKE_Q_H
+
+#include <linux/sched.h>
+
+#endif /* _LINUX_SCHED_WAKE_Q_H */

ipc/mqueue.c

@@ -35,6 +35,7 @@
 #include <linux/ipc_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/slab.h>
+#include <linux/sched/wake_q.h>
 
 #include <net/sock.h>
 #include "util.h"

ipc/msg.c

@@ -31,6 +31,7 @@
 #include <linux/list.h>
 #include <linux/security.h>
 #include <linux/sched.h>
+#include <linux/sched/wake_q.h>
 #include <linux/syscalls.h>
 #include <linux/audit.h>
 #include <linux/seq_file.h>

ipc/sem.c

@@ -82,6 +82,7 @@
 #include <linux/rwsem.h>
 #include <linux/nsproxy.h>
 #include <linux/ipc_namespace.h>
+#include <linux/sched/wake_q.h>
 
 #include <linux/uaccess.h>
 #include "util.h"

kernel/futex.c

@@ -61,6 +61,7 @@
 #include <linux/nsproxy.h>
 #include <linux/ptrace.h>
 #include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
 #include <linux/hugetlb.h>
 #include <linux/freezer.h>
 #include <linux/bootmem.h>

kernel/locking/mutex.c

@@ -21,6 +21,7 @@
 #include <linux/ww_mutex.h>
 #include <linux/sched.h>
 #include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
 #include <linux/export.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>

kernel/locking/rtmutex.c

@@ -15,6 +15,7 @@
 #include <linux/sched.h>
 #include <linux/sched/rt.h>
 #include <linux/sched/deadline.h>
+#include <linux/sched/wake_q.h>
 #include <linux/timer.h>
 
 #include "rtmutex_common.h"

kernel/locking/rtmutex_common.h

@@ -13,6 +13,7 @@
 #define __KERNEL_RTMUTEX_COMMON_H
 
 #include <linux/rtmutex.h>
+#include <linux/sched/wake_q.h>
 
 /*
  * This is the control structure for tasks blocked on a rt_mutex,

kernel/locking/rwsem-xadd.c

@@ -10,10 +10,11 @@
  * and Davidlohr Bueso <davidlohr@hp.com>. Based on mutexes.
  */
 #include <linux/rwsem.h>
-#include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/export.h>
+#include <linux/sched.h>
 #include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
 #include <linux/osq_lock.h>
 
 #include "rwsem.h"

kernel/sched/sched.h

@@ -3,6 +3,7 @@
 #include <linux/sched/sysctl.h>
 #include <linux/sched/topology.h>
 #include <linux/sched/rt.h>
+#include <linux/sched/wake_q.h>
 #include <linux/u64_stats_sync.h>
 #include <linux/sched/deadline.h>
 #include <linux/kernel_stat.h>