[PATCH 03/10] sched/headers: Make task_struct::wake_q an opaque pointer

[Ingo Molnar]

To be able to decouple wake_q functionality from <linux/sched.h> make
the basic task_struct::wake_q pointer an opaque void *.

Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/sched.h | 2 +-
 kernel/fork.c         | 2 +-
 kernel/sched/core.c   | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 54651e828ac4..255780f95de1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1725,7 +1725,7 @@ struct task_struct {
 	/* Protection of the PI data structures: */
 	raw_spinlock_t pi_lock;
 
-	struct wake_q_node wake_q;
+	void *wake_q;
 
 #ifdef CONFIG_RT_MUTEXES
 	/* PI waiters blocked on a rt_mutex held by this task */
diff --git a/kernel/fork.c b/kernel/fork.c
index 077ce3b4c0ef..9aa2ca28a76c 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -538,7 +538,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
 #endif
 	tsk->splice_pipe = NULL;
 	tsk->task_frag.page = NULL;
-	tsk->wake_q.next = NULL;
+	tsk->wake_q = NULL;
 
 	account_kernel_stack(tsk, 1);
 
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 675647b0b84b..c4cebf6628de 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -426,7 +426,7 @@ static bool set_nr_if_polling(struct task_struct *p)
 
 void wake_q_add(struct wake_q_head *head, struct task_struct *task)
 {
-	struct wake_q_node *node = &task->wake_q;
+	struct wake_q_node *node = (void *)&task->wake_q;
 
 	/*
 	 * Atomically grab the task, if ->wake_q is !nil already it means
@@ -455,11 +455,11 @@ void wake_up_q(struct wake_q_head *head)
 	while (node != WAKE_Q_TAIL) {
 		struct task_struct *task;
 
-		task = container_of(node, struct task_struct, wake_q);
+		task = container_of((void *)node, struct task_struct, wake_q);
 		BUG_ON(!task);
 		/* Task can safely be re-inserted now: */
 		node = node->next;
-		task->wake_q.next = NULL;
+		task->wake_q = NULL;
 
 		/*
 		 * wake_up_process() implies a wmb() to pair with the queueing
-- 
2.7.4