mango/include/kernel/wait.h

#ifndef KERNEL_WAIT_H_
#define KERNEL_WAIT_H_

#include <kernel/locks.h>
#include <kernel/queue.h>

#define wait_event(wq, cond)                                                   \
	({                                                                     \
		struct thread *self = current_thread();                        \
		struct wait_item waiter;                                       \
		wait_item_init(&waiter, self);                                 \
		for (;;) {                                                     \
			thread_wait_begin(&waiter, wq);                        \
			if (cond) {                                            \
				break;                                         \
			}                                                      \
			schedule(SCHED_NORMAL);                                \
		}                                                              \
		thread_wait_end(&waiter, wq);                                  \
	})

struct wait_item {
	struct thread *w_thread;
	struct queue_entry w_entry;
};

struct waitqueue {
	struct queue wq_waiters;
	spin_lock_t wq_lock;
};

extern void wait_item_init(struct wait_item *item, struct thread *thr);
extern void thread_wait_begin(struct wait_item *waiter, struct waitqueue *q);
extern void thread_wait_end(struct wait_item *waiter, struct waitqueue *q);
extern void thread_wait_begin_nosleep(
	struct wait_item *waiter,
	struct waitqueue *q);
extern void thread_wait_end_nosleep(
	struct wait_item *waiter,
	struct waitqueue *q);
extern void wait_on_queue(struct waitqueue *q);
extern void wakeup_queue(struct waitqueue *q);
extern void wakeup_n(struct waitqueue *q, size_t n);
extern void wakeup_one(struct waitqueue *q);
static inline bool waitqueue_empty(struct waitqueue *wq)
{
	unsigned long flags;
	spin_lock_irqsave(&wq->wq_lock, &flags);
	bool result = queue_empty(&wq->wq_waiters);
	spin_unlock_irqrestore(&wq->wq_lock, flags);
	return result;
}

#endif