sched/headers: Move the wake-queue types and interfaces from sched.h into <linux/sched/wake_q.h>

Acked-by: Linus Torvalds <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

include/linux/sched.h

···
 # define SCHED_FIXEDPOINT_SHIFT	10
 # define SCHED_FIXEDPOINT_SCALE	(1L << SCHED_FIXEDPOINT_SHIFT)
 
-/*
- * Wake-queues are lists of tasks with a pending wakeup, whose
- * callers have already marked the task as woken internally,
- * and can thus carry on. A common use case is being able to
- * do the wakeups once the corresponding user lock as been
- * released.
- *
- * We hold reference to each task in the list across the wakeup,
- * thus guaranteeing that the memory is still valid by the time
- * the actual wakeups are performed in wake_up_q().
- *
- * One per task suffices, because there's never a need for a task to be
- * in two wake queues simultaneously; it is forbidden to abandon a task
- * in a wake queue (a call to wake_up_q() _must_ follow), so if a task is
- * already in a wake queue, the wakeup will happen soon and the second
- * waker can just skip it.
- *
- * The DEFINE_WAKE_Q macro declares and initializes the list head.
- * wake_up_q() does NOT reinitialize the list; it's expected to be
- * called near the end of a function. Otherwise, the list can be
- * re-initialized for later re-use by wake_q_init().
- *
- * Note that this can cause spurious wakeups. schedule() callers
- * must ensure the call is done inside a loop, confirming that the
- * wakeup condition has in fact occurred.
- */
-struct wake_q_node {
-	struct wake_q_node *next;
-};
-
-struct wake_q_head {
-	struct wake_q_node *first;
-	struct wake_q_node **lastp;
-};
-
-#define WAKE_Q_TAIL ((struct wake_q_node *) 0x01)
-
-#define DEFINE_WAKE_Q(name)				\
-	struct wake_q_head name = { WAKE_Q_TAIL, &name.first }
-
-static inline void wake_q_init(struct wake_q_head *head)
-{
-	head->first = WAKE_Q_TAIL;
-	head->lastp = &head->first;
-}
-
-extern void wake_q_add(struct wake_q_head *head,
-		       struct task_struct *task);
-extern void wake_up_q(struct wake_q_head *head);
-
 struct io_context;			/* See blkdev.h */
 
 
···
 	perf_hw_context = 0,
 	perf_sw_context,
 	perf_nr_task_contexts,
+};
+
+struct wake_q_node {
+	struct wake_q_node *next;
 };
 
 /* Track pages that require TLB flushes */

include/linux/sched/wake_q.h

···
 #ifndef _LINUX_SCHED_WAKE_Q_H
 #define _LINUX_SCHED_WAKE_Q_H
 
+/*
+ * Wake-queues are lists of tasks with a pending wakeup, whose
+ * callers have already marked the task as woken internally,
+ * and can thus carry on. A common use case is being able to
+ * do the wakeups once the corresponding user lock as been
+ * released.
+ *
+ * We hold reference to each task in the list across the wakeup,
+ * thus guaranteeing that the memory is still valid by the time
+ * the actual wakeups are performed in wake_up_q().
+ *
+ * One per task suffices, because there's never a need for a task to be
+ * in two wake queues simultaneously; it is forbidden to abandon a task
+ * in a wake queue (a call to wake_up_q() _must_ follow), so if a task is
+ * already in a wake queue, the wakeup will happen soon and the second
+ * waker can just skip it.
+ *
+ * The DEFINE_WAKE_Q macro declares and initializes the list head.
+ * wake_up_q() does NOT reinitialize the list; it's expected to be
+ * called near the end of a function. Otherwise, the list can be
+ * re-initialized for later re-use by wake_q_init().
+ *
+ * Note that this can cause spurious wakeups. schedule() callers
+ * must ensure the call is done inside a loop, confirming that the
+ * wakeup condition has in fact occurred.
+ */
+
 #include <linux/sched.h>
+
+struct wake_q_head {
+	struct wake_q_node *first;
+	struct wake_q_node **lastp;
+};
+
+#define WAKE_Q_TAIL ((struct wake_q_node *) 0x01)
+
+#define DEFINE_WAKE_Q(name)				\
+	struct wake_q_head name = { WAKE_Q_TAIL, &name.first }
+
+static inline void wake_q_init(struct wake_q_head *head)
+{
+	head->first = WAKE_Q_TAIL;
+	head->lastp = &head->first;
+}
+
+extern void wake_q_add(struct wake_q_head *head,
+		       struct task_struct *task);
+extern void wake_up_q(struct wake_q_head *head);
 
 #endif /* _LINUX_SCHED_WAKE_Q_H */

ipc/msg.c

···
 #include <linux/proc_fs.h>
 #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>