Initial commit

include/l4/lib/wait.h

@@ -0,0 +1,45 @@
+#ifndef __LIB_WAIT_H__
+#define __LIB_WAIT_H__
+
+#include <l4/lib/list.h>
+#include <l4/lib/spinlock.h>
+
+struct ktcb;
+struct waitqueue {
+	struct list_head task_list;
+	struct ktcb *task;
+};
+
+#define DECLARE_WAITQUEUE(wq, tsk)			\
+struct waitqueue wq = {					\
+	.task_list = { &wq.task_list, &wq.task_list },	\
+	.task = tsk,					\
+};
+//	LIST_HEAD_INIT(task_list),
+
+/*
+ * The waitqueue spinlock ensures waiters are added and removed atomically so
+ * that wake-ups and sleeps occur in sync. Otherwise, a task could try to wake
+ * up a waitqueue **during when a task has decided to sleep but is not in the
+ * queue yet. (** Take "during" here as a pseudo-concurrency term on UP)
+ */
+struct waitqueue_head {
+	int sleepers;
+	struct spinlock slock;		/* Locks sleeper queue */
+	struct list_head task_list;	/* Sleeper queue head */
+};
+
+static inline void waitqueue_head_init(struct waitqueue_head *head)
+{
+	memset(head, 0, sizeof(struct waitqueue_head));
+	INIT_LIST_HEAD(&head->task_list);
+}
+
+/*
+ * Used for ipc related waitqueues who have special wait queue manipulation
+ * conditions.
+ */
+void wake_up(struct waitqueue_head *wqh);
+
+#endif /* __LIB_WAIT_H__ */
+