/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2000 Doug Rabson
 * 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, 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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 _SYS_TASKQUEUE_H_
#define _SYS_TASKQUEUE_H_

#ifndef _KERNEL
#error "no user-serviceable parts inside"
#endif

#include <sys/queue.h>
#include <sys/_task.h>
#include <sys/_cpuset.h>

struct taskqueue;
struct taskqgroup;
struct proc;
struct thread;

enum taskqueue_callback_type {
        TASKQUEUE_CALLBACK_TYPE_INIT,
        TASKQUEUE_CALLBACK_TYPE_SHUTDOWN,
};
#define TASKQUEUE_CALLBACK_TYPE_MIN     TASKQUEUE_CALLBACK_TYPE_INIT
#define TASKQUEUE_CALLBACK_TYPE_MAX     TASKQUEUE_CALLBACK_TYPE_SHUTDOWN
#define TASKQUEUE_NUM_CALLBACKS         TASKQUEUE_CALLBACK_TYPE_MAX + 1
#define TASKQUEUE_NAMELEN               32

/* taskqueue_enqueue flags */
#define TASKQUEUE_FAIL_IF_PENDING       (1 << 0)
#define TASKQUEUE_FAIL_IF_CANCELING     (1 << 1)

typedef void (*taskqueue_callback_fn)(void *context);

/*
 * A notification callback function which is called from
 * taskqueue_enqueue().  The context argument is given in the call to
 * taskqueue_create().  This function would normally be used to allow the
 * queue to arrange to run itself later (e.g., by scheduling a software
 * interrupt or waking a kernel thread).
 */
typedef void (*taskqueue_enqueue_fn)(void *context);

struct taskqueue *taskqueue_create(const char *name, int mflags,
                                    taskqueue_enqueue_fn enqueue,
                                    void *context);
int     taskqueue_start_threads(struct taskqueue **tqp, int count, int pri,
            const char *name, ...) __printflike(4, 5);
int     taskqueue_start_threads_in_proc(struct taskqueue **tqp, int count,
            int pri, struct proc *p, const char *name, ...) __printflike(5, 6);
int     taskqueue_start_threads_cpuset(struct taskqueue **tqp, int count,
            int pri, cpuset_t *mask, const char *name, ...) __printflike(5, 6);
int     taskqueue_enqueue(struct taskqueue *queue, struct task *task);
int     taskqueue_enqueue_flags(struct taskqueue *queue, struct task *task,
            int flags);
int     taskqueue_enqueue_timeout(struct taskqueue *queue,
            struct timeout_task *timeout_task, int ticks);
int     taskqueue_enqueue_timeout_sbt(struct taskqueue *queue,
            struct timeout_task *timeout_task, sbintime_t sbt, sbintime_t pr,
            int flags);
int     taskqueue_poll_is_busy(struct taskqueue *queue, struct task *task);
int     taskqueue_cancel(struct taskqueue *queue, struct task *task,
            u_int *pendp);
int     taskqueue_cancel_timeout(struct taskqueue *queue,
            struct timeout_task *timeout_task, u_int *pendp);
void    taskqueue_drain(struct taskqueue *queue, struct task *task);
void    taskqueue_drain_timeout(struct taskqueue *queue,
            struct timeout_task *timeout_task);
void    taskqueue_drain_all(struct taskqueue *queue);
void    taskqueue_quiesce(struct taskqueue *queue);
void    taskqueue_free(struct taskqueue *queue);
void    taskqueue_run(struct taskqueue *queue);
void    taskqueue_block(struct taskqueue *queue);
void    taskqueue_unblock(struct taskqueue *queue);
int     taskqueue_member(struct taskqueue *queue, struct thread *td);
void    taskqueue_set_callback(struct taskqueue *queue,
            enum taskqueue_callback_type cb_type,
            taskqueue_callback_fn callback, void *context);

#define TASK_INITIALIZER(priority, func, context)       \
        { .ta_priority = (priority),                    \
          .ta_func = (func),                            \
          .ta_context = (context) }

/*
 * Functions for dedicated thread taskqueues
 */
void    taskqueue_thread_loop(void *arg);
void    taskqueue_thread_enqueue(void *context);

/*
 * Initialise a task structure.
 */
#define TASK_INIT_FLAGS(task, priority, func, context, flags) do {      \
        (task)->ta_pending = 0;                                 \
        (task)->ta_priority = (priority);                       \
        (task)->ta_flags = (flags);                             \
        (task)->ta_func = (func);                               \
        (task)->ta_context = (context);                         \
} while (0)

#define TASK_INIT(t, p, f, c)   TASK_INIT_FLAGS(t, p, f, c, 0)

void _timeout_task_init(struct taskqueue *queue,
            struct timeout_task *timeout_task, int priority, task_fn_t func,
            void *context);
#define TIMEOUT_TASK_INIT(queue, timeout_task, priority, func, context) do { \
        _Static_assert((priority) >= 0 && (priority) <= 255,    \
            "struct task priority is 8 bit in size");           \
        _timeout_task_init(queue, timeout_task, priority, func, context); \
} while (0)

/*
 * Declare a reference to a taskqueue.
 */
#define TASKQUEUE_DECLARE(name)                 \
extern struct taskqueue *taskqueue_##name

/*
 * Define and initialise a global taskqueue that uses sleep mutexes.
 */
#define TASKQUEUE_DEFINE(name, enqueue, context, init)                  \
                                                                        \
struct taskqueue *taskqueue_##name;                                     \
                                                                        \
static void                                                             \
taskqueue_define_##name(void *arg)                                      \
{                                                                       \
        taskqueue_##name =                                              \
            taskqueue_create(#name, M_WAITOK, (enqueue), (context));    \
        init;                                                           \
}                                                                       \
                                                                        \
SYSINIT(taskqueue_##name, SI_SUB_TASKQ, SI_ORDER_SECOND,                \
        taskqueue_define_##name, NULL);                                 \
                                                                        \
struct __hack
#define TASKQUEUE_DEFINE_THREAD(name)                                   \
TASKQUEUE_DEFINE(name, taskqueue_thread_enqueue, &taskqueue_##name,     \
        taskqueue_start_threads(&taskqueue_##name, 1, PWAIT,            \
        "%s taskq", #name))

/*
 * Define and initialise a global taskqueue that uses spin mutexes.
 */
#define TASKQUEUE_FAST_DEFINE(name, enqueue, context, init)             \
                                                                        \
struct taskqueue *taskqueue_##name;                                     \
                                                                        \
static void                                                             \
taskqueue_define_##name(void *arg)                                      \
{                                                                       \
        taskqueue_##name =                                              \
            taskqueue_create_fast(#name, M_WAITOK, (enqueue),           \
            (context));                                                 \
        init;                                                           \
}                                                                       \
                                                                        \
SYSINIT(taskqueue_##name, SI_SUB_TASKQ, SI_ORDER_SECOND,                \
        taskqueue_define_##name, NULL);                                 \
                                                                        \
struct __hack
#define TASKQUEUE_FAST_DEFINE_THREAD(name)                              \
TASKQUEUE_FAST_DEFINE(name, taskqueue_thread_enqueue,                   \
        &taskqueue_##name, taskqueue_start_threads(&taskqueue_##name,   \
        1, PWAIT, "%s taskq", #name))

/*
 * These queues are serviced by software interrupt handlers.  To enqueue
 * a task, call taskqueue_enqueue(taskqueue_swi, &task) or
 * taskqueue_enqueue(taskqueue_swi_giant, &task).
 */
TASKQUEUE_DECLARE(swi_giant);
TASKQUEUE_DECLARE(swi);

/*
 * This queue is serviced by a kernel thread.  To enqueue a task, call
 * taskqueue_enqueue(taskqueue_thread, &task).
 */
TASKQUEUE_DECLARE(thread);

/*
 * Queue for swi handlers dispatched from fast interrupt handlers.
 * These are necessarily different from the above because the queue
 * must be locked with spinlocks since sleep mutex's cannot be used
 * from a fast interrupt handler context.
 */
TASKQUEUE_DECLARE(fast);
struct taskqueue *taskqueue_create_fast(const char *name, int mflags,
                                    taskqueue_enqueue_fn enqueue,
                                    void *context);

/*
 * This queue is used to process asynchronous device events such as
 * hot plug insertion and removal of devices.
 */
TASKQUEUE_DECLARE(bus);

#endif /* !_SYS_TASKQUEUE_H_ */