/******************************************************************************

 * wait.h

 * 

 * Sleep in hypervisor context for some event to occur.

 * 

 * Copyright (c) 2010, Keir Fraser <keir@xen.org>

 */

#ifndef __XEN_WAIT_H__

#define __XEN_WAIT_H__

#include <xen/types.h>

#include <xen/list.h>

#include <xen/spinlock.h>

struct waitqueue_head {

    spinlock_t lock;

    struct list_head list;

};

/* Statically define and initialise a waitqueue. */

#define DEFINE_WAITQUEUE_HEAD(name)             \

    struct waitqueue_head name = {              \

        .lock = SPIN_LOCK_UNLOCKED,             \

        .list = LIST_HEAD_INIT((name).list)     \

    }

/* Dynamically initialise/destroy a waitqueue. */

void init_waitqueue_head(struct waitqueue_head *wq);

void destroy_waitqueue_head(struct waitqueue_head *wq);

/* Wake VCPU(s) waiting on specified waitqueue. */

void wake_up_nr(struct waitqueue_head *wq, unsigned int nr);

void wake_up_one(struct waitqueue_head *wq);

void wake_up_all(struct waitqueue_head *wq);

/* Wait on specified waitqueue until @condition is true. */

#define wait_event(wq, condition)               \

do {                                            \

    if ( condition )                            \

        break;                                  \

    for ( ; ; ) {                               \

        prepare_to_wait(&wq);                   \

        if ( condition )                        \

            break;                              \

        wait();                                 \

    }                                           \

    finish_wait(&wq);                           \

} while (0)

/* Private functions. */

int init_waitqueue_vcpu(struct vcpu *v);

void destroy_waitqueue_vcpu(struct vcpu *v);

void prepare_to_wait(struct waitqueue_head *wq);

void wait(void);

void finish_wait(struct waitqueue_head *wq);

void check_wakeup_from_wait(void);

#endif /* __XEN_WAIT_H__ */