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

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>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 4 insertions, 50 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4f512e337584..5cda7cf09505 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -953,56 +953,6 @@ void force_schedstat_enabled(void);
 # 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 */
 
 
@@ -1234,6 +1184,10 @@ enum perf_event_task_context {
 	perf_nr_task_contexts,
 };
 
+struct wake_q_node {
+	struct wake_q_node *next;
+};
+
 /* Track pages that require TLB flushes */
 struct tlbflush_unmap_batch {
 	/*