/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
 * Copyright (c) 2017 Mark Johnston <markj@FreeBSD.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _LINUXKPI_LINUX_WAIT_H_
#define _LINUXKPI_LINUX_WAIT_H_

#include <linux/compiler.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/sched.h>

#include <asm/atomic.h>

#include <sys/param.h>
#include <sys/systm.h>

#define SKIP_SLEEP() (SCHEDULER_STOPPED() || kdb_active)

#define might_sleep()                                                   \
        WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "might_sleep()")

#define might_sleep_if(cond) do { \
        if (cond) { might_sleep(); } \
} while (0)

struct wait_queue;
struct wait_queue_head;

#define wait_queue_entry wait_queue

typedef struct wait_queue wait_queue_t;
typedef struct wait_queue_entry wait_queue_entry_t;
typedef struct wait_queue_head wait_queue_head_t;

typedef int wait_queue_func_t(wait_queue_t *, unsigned int, int, void *);

#define WQ_FLAG_WOKEN           0x02

/*
 * Many API consumers directly reference these fields and those of
 * wait_queue_head.
 */
struct wait_queue {
        unsigned int flags;
        void *private;
        wait_queue_func_t *func;
        union {
                struct list_head task_list; /* < v4.13 */
                struct list_head entry; /* >= v4.13 */
        };
};

struct wait_queue_head {
        spinlock_t lock;
        union {
                struct list_head task_list; /* < v4.13 */
                struct list_head head; /* >= v4.13 */
        };
};

/*
 * This function is referenced by at least one DRM driver, so it may not be
 * renamed and furthermore must be the default wait queue callback.
 */
wait_queue_func_t autoremove_wake_function;
wait_queue_func_t default_wake_function;
wait_queue_func_t woken_wake_function;

long linux_wait_woken(wait_queue_t *wq, unsigned state, long timeout);

#define wait_woken(wq, state, timeout) \
        linux_wait_woken((wq), (state), (timeout))

#define DEFINE_WAIT_FUNC(name, function)                                \
        wait_queue_t name = {                                           \
                .private = current,                                     \
                .func = function,                                       \
                .task_list = LINUX_LIST_HEAD_INIT(name.task_list)       \
        }

#define DEFINE_WAIT(name) \
        DEFINE_WAIT_FUNC(name, autoremove_wake_function)

#define DECLARE_WAITQUEUE(name, task)                                   \
        wait_queue_t name = {                                           \
                .private = task,                                        \
                .task_list = LINUX_LIST_HEAD_INIT(name.task_list)       \
        }

#define DECLARE_WAIT_QUEUE_HEAD(name)                                   \
        wait_queue_head_t name = {                                      \
                .task_list = LINUX_LIST_HEAD_INIT(name.task_list),      \
        };                                                              \
        MTX_SYSINIT(name, &(name).lock, spin_lock_name("wqhead"), MTX_DEF)

#define init_waitqueue_head(wqh) do {                                   \
        mtx_init(&(wqh)->lock, spin_lock_name("wqhead"),                \
            NULL, MTX_DEF | MTX_NEW | MTX_NOWITNESS);                   \
        INIT_LIST_HEAD(&(wqh)->task_list);                              \
} while (0)

#define __init_waitqueue_head(wqh, name, lk) init_waitqueue_head(wqh)

void linux_init_wait_entry(wait_queue_t *, int);
void linux_wake_up(wait_queue_head_t *, unsigned int, int, bool);

#define init_wait_entry(wq, flags)                                      \
        linux_init_wait_entry(wq, flags)
#define wake_up(wqh)                                                    \
        linux_wake_up(wqh, TASK_NORMAL, 1, false)
#define wake_up_all(wqh)                                                \
        linux_wake_up(wqh, TASK_NORMAL, 0, false)
#define wake_up_locked(wqh)                                             \
        linux_wake_up(wqh, TASK_NORMAL, 1, true)
#define wake_up_all_locked(wqh)                                         \
        linux_wake_up(wqh, TASK_NORMAL, 0, true)
#define wake_up_interruptible(wqh)                                      \
        linux_wake_up(wqh, TASK_INTERRUPTIBLE, 1, false)
#define wake_up_interruptible_all(wqh)                                  \
        linux_wake_up(wqh, TASK_INTERRUPTIBLE, 0, false)

int linux_wait_event_common(wait_queue_head_t *, wait_queue_t *, long,
    unsigned int, spinlock_t *);

/*
 * Returns -ERESTARTSYS for a signal, 0 if cond is false after timeout, 1 if
 * cond is true after timeout, remaining jiffies (> 0) if cond is true before
 * timeout.
 */
#define __wait_event_common(wqh, cond, timeout, state, lock) ({ \
        DEFINE_WAIT(__wq);                                      \
        const long __timeout = ((long)(timeout)) < 1 ? 1 : (timeout); \
        long __start = jiffies;                                 \
        long __ret = 0;                                         \
                                                                \
        for (;;) {                                              \
                linux_prepare_to_wait(&(wqh), &__wq, state);    \
                if (cond)                                       \
                        break;                                  \
                __ret = linux_wait_event_common(&(wqh), &__wq,  \
                    __timeout, state, lock);                    \
                if (__ret != 0)                                 \
                        break;                                  \
        }                                                       \
        linux_finish_wait(&(wqh), &__wq);                       \
        if (__timeout != MAX_SCHEDULE_TIMEOUT) {                \
                if (__ret == -EWOULDBLOCK)                      \
                        __ret = !!(cond);                       \
                else if (__ret != -ERESTARTSYS) {               \
                        __ret = __timeout + __start - jiffies;  \
                        /* range check return value */          \
                        if (__ret < 1)                          \
                                __ret = 1;                      \
                        else if (__ret > __timeout)             \
                                __ret = __timeout;              \
                }                                               \
        }                                                       \
        __ret;                                                  \
})

#define wait_event(wqh, cond) do {                                      \
        (void) __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,     \
            TASK_UNINTERRUPTIBLE, NULL);                                \
} while (0)

#define wait_event_timeout(wqh, cond, timeout) ({                       \
        __wait_event_common(wqh, cond, timeout, TASK_UNINTERRUPTIBLE,   \
            NULL);                                                      \
})

#define wait_event_killable(wqh, cond) ({                               \
        __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,            \
            TASK_INTERRUPTIBLE, NULL);                                  \
})

#define wait_event_interruptible(wqh, cond) ({                          \
        __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,            \
            TASK_INTERRUPTIBLE, NULL);                                  \
})

#define wait_event_interruptible_timeout(wqh, cond, timeout) ({         \
        __wait_event_common(wqh, cond, timeout, TASK_INTERRUPTIBLE,     \
            NULL);                                                      \
})

/*
 * Wait queue is already locked.
 */
#define wait_event_interruptible_locked(wqh, cond) ({                   \
        int __ret;                                                      \
                                                                        \
        spin_unlock(&(wqh).lock);                                       \
        __ret = __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,    \
            TASK_INTERRUPTIBLE, NULL);                                  \
        spin_lock(&(wqh).lock);                                         \
        __ret;                                                          \
})

/*
 * The passed spinlock is held when testing the condition.
 */
#define wait_event_interruptible_lock_irq(wqh, cond, lock) ({           \
        __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,            \
            TASK_INTERRUPTIBLE, &(lock));                               \
})

/*
 * The passed spinlock is held when testing the condition.
 */
#define wait_event_lock_irq(wqh, cond, lock) ({                 \
        __wait_event_common(wqh, cond, MAX_SCHEDULE_TIMEOUT,    \
            TASK_UNINTERRUPTIBLE, &(lock));                     \
})

static inline void
__add_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
{
        list_add(&wq->task_list, &wqh->task_list);
}

static inline void
add_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
{

        spin_lock(&wqh->lock);
        __add_wait_queue(wqh, wq);
        spin_unlock(&wqh->lock);
}

static inline void
__add_wait_queue_tail(wait_queue_head_t *wqh, wait_queue_t *wq)
{
        list_add_tail(&wq->task_list, &wqh->task_list);
}

static inline void
__add_wait_queue_entry_tail(wait_queue_head_t *wqh, wait_queue_entry_t *wq)
{
        list_add_tail(&wq->entry, &wqh->head);
}

static inline void
__remove_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
{
        list_del(&wq->task_list);
}

static inline void
remove_wait_queue(wait_queue_head_t *wqh, wait_queue_t *wq)
{

        spin_lock(&wqh->lock);
        __remove_wait_queue(wqh, wq);
        spin_unlock(&wqh->lock);
}

bool linux_waitqueue_active(wait_queue_head_t *);

#define waitqueue_active(wqh)           linux_waitqueue_active(wqh)

void linux_prepare_to_wait(wait_queue_head_t *, wait_queue_t *, int);
void linux_finish_wait(wait_queue_head_t *, wait_queue_t *);

#define prepare_to_wait(wqh, wq, state) linux_prepare_to_wait(wqh, wq, state)
#define finish_wait(wqh, wq)            linux_finish_wait(wqh, wq)

void linux_wake_up_bit(void *, int);
int linux_wait_on_bit_timeout(unsigned long *, int, unsigned int, long);
void linux_wake_up_atomic_t(atomic_t *);
int linux_wait_on_atomic_t(atomic_t *, unsigned int);

#define wake_up_bit(word, bit)          linux_wake_up_bit(word, bit)
#define wait_on_bit(word, bit, state)                                   \
        linux_wait_on_bit_timeout(word, bit, state, MAX_SCHEDULE_TIMEOUT)
#define wait_on_bit_timeout(word, bit, state, timeout)                  \
        linux_wait_on_bit_timeout(word, bit, state, timeout)
#define wake_up_atomic_t(a)             linux_wake_up_atomic_t(a)
/*
 * All existing callers have a cb that just schedule()s. To avoid adding
 * complexity, just emulate that internally. The prototype is different so that
 * callers must be manually modified; a cb that does something other than call
 * schedule() will require special treatment.
 */
#define wait_on_atomic_t(a, state)      linux_wait_on_atomic_t(a, state)

struct task_struct;
bool linux_wake_up_state(struct task_struct *, unsigned int);

#define wake_up_process(task)           linux_wake_up_state(task, TASK_NORMAL)
#define wake_up_state(task, state)      linux_wake_up_state(task, state)

#endif /* _LINUXKPI_LINUX_WAIT_H_ */