/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013-2018 Mellanox Technologies, Ltd.
 * 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_SCHED_H_
#define _LINUXKPI_LINUX_SCHED_H_

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/rtprio.h>
#include <sys/sched.h>
#include <sys/sleepqueue.h>
#include <sys/time.h>

#include <linux/bitmap.h>
#include <linux/compat.h>
#include <linux/completion.h>
#include <linux/hrtimer.h>
#include <linux/mm_types.h>
#include <linux/nodemask.h>
#include <linux/pid.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/time.h>

#include <linux/sched/mm.h>

#include <asm/atomic.h>

#define MAX_SCHEDULE_TIMEOUT    LONG_MAX

#define TASK_RUNNING            0x0000
#define TASK_INTERRUPTIBLE      0x0001
#define TASK_UNINTERRUPTIBLE    0x0002
#define TASK_NORMAL             (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
#define TASK_WAKING             0x0100
#define TASK_PARKED             0x0200

#define TASK_COMM_LEN           (MAXCOMLEN + 1)

struct seq_file;

struct work_struct;
struct task_struct {
        struct thread *task_thread;
        struct mm_struct *mm;
        linux_task_fn_t *task_fn;
        void   *task_data;
        int     task_ret;
        atomic_t usage;
        atomic_t state;
        atomic_t kthread_flags;
        pid_t   pid;    /* BSD thread ID */
        const char    *comm;
        void   *bsd_ioctl_data;
        unsigned bsd_ioctl_len;
        struct completion parked;
        struct completion exited;
#define TS_RCU_TYPE_MAX 2
        TAILQ_ENTRY(task_struct) rcu_entry[TS_RCU_TYPE_MAX];
        int rcu_recurse[TS_RCU_TYPE_MAX];
        int bsd_interrupt_value;
        struct work_struct *work;       /* current work struct, if set */
        struct task_struct *group_leader;
        unsigned rcu_section[TS_RCU_TYPE_MAX];
        unsigned int fpu_ctx_level;
};

#define current ({ \
        struct thread *__td = curthread; \
        linux_set_current(__td); \
        ((struct task_struct *)__td->td_lkpi_task); \
})

#define task_pid_group_leader(task) (task)->task_thread->td_proc->p_pid
#define task_pid(task)          ((task)->pid)
#define task_pid_nr(task)       ((task)->pid)
#define task_pid_vnr(task)      ((task)->pid)
#define get_pid(x)              (x)
#define put_pid(x)              do { } while (0)
#define current_euid()  (curthread->td_ucred->cr_uid)
#define task_euid(task) ((task)->task_thread->td_ucred->cr_uid)

#define get_task_state(task)            atomic_read(&(task)->state)
#define set_task_state(task, x)         atomic_set(&(task)->state, (x))
#define __set_task_state(task, x)       ((task)->state.counter = (x))
#define set_current_state(x)            set_task_state(current, x)
#define __set_current_state(x)          __set_task_state(current, x)

static inline void
get_task_struct(struct task_struct *task)
{
        atomic_inc(&task->usage);
}

static inline void
put_task_struct(struct task_struct *task)
{
        if (atomic_dec_and_test(&task->usage))
                linux_free_current(task);
}

#define cond_resched()  do { if (!cold) sched_relinquish(curthread); } while (0)

#define yield()         kern_yield(PRI_UNCHANGED)
#define sched_yield()   sched_relinquish(curthread)

#define need_resched()  (curthread->td_owepreempt || \
    td_ast_pending(curthread, TDA_SCHED))

static inline int
cond_resched_lock(spinlock_t *lock)
{

        if (need_resched() == 0)
                return (0);
        spin_unlock(lock);
        cond_resched();
        spin_lock(lock);
        return (1);
}

bool linux_signal_pending(struct task_struct *task);
bool linux_fatal_signal_pending(struct task_struct *task);
bool linux_signal_pending_state(long state, struct task_struct *task);
void linux_send_sig(int signo, struct task_struct *task);

#define signal_pending(task)            linux_signal_pending(task)
#define fatal_signal_pending(task)      linux_fatal_signal_pending(task)
#define signal_pending_state(state, task)               \
        linux_signal_pending_state(state, task)
#define send_sig(signo, task, priv) do {                \
        CTASSERT((priv) == 0);                          \
        linux_send_sig(signo, task);                    \
} while (0)

long linux_schedule_timeout(long timeout);

static inline void
linux_schedule_save_interrupt_value(struct task_struct *task, int value)
{
        task->bsd_interrupt_value = value;
}

bool linux_task_exiting(struct task_struct *task);

#define current_exiting() \
        linux_task_exiting(current)

static inline int
linux_schedule_get_interrupt_value(struct task_struct *task)
{
        int value = task->bsd_interrupt_value;
        task->bsd_interrupt_value = 0;
        return (value);
}

static inline void
schedule(void)
{
        (void)linux_schedule_timeout(MAX_SCHEDULE_TIMEOUT);
}

#define schedule_timeout(timeout)                       \
        linux_schedule_timeout(timeout)
#define schedule_timeout_killable(timeout)              \
        schedule_timeout_interruptible(timeout)
#define schedule_timeout_interruptible(timeout) ({      \
        set_current_state(TASK_INTERRUPTIBLE);          \
        schedule_timeout(timeout);                      \
})
#define schedule_timeout_uninterruptible(timeout) ({    \
        set_current_state(TASK_UNINTERRUPTIBLE);        \
        schedule_timeout(timeout);                      \
})

#define io_schedule()                   schedule()
#define io_schedule_timeout(timeout)    schedule_timeout(timeout)

static inline uint64_t
local_clock(void)
{
        struct timespec ts;

        nanotime(&ts);
        return ((uint64_t)ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec);
}

static inline const char *
get_task_comm(char *buf, struct task_struct *task)
{

        buf[0] = 0; /* buffer is too small */
        return (task->comm);
}

static inline void
sched_set_fifo(struct task_struct *t)
{
        struct rtprio rtp;

        rtp.prio = (RTP_PRIO_MIN + RTP_PRIO_MAX) / 2;
        rtp.type = RTP_PRIO_FIFO;
        rtp_to_pri(&rtp, t->task_thread);
}

static inline void
sched_set_fifo_low(struct task_struct *t)
{
        struct rtprio rtp;

        rtp.prio = RTP_PRIO_MAX;        /* lowest priority */
        rtp.type = RTP_PRIO_FIFO;
        rtp_to_pri(&rtp, t->task_thread);
}

#endif  /* _LINUXKPI_LINUX_SCHED_H_ */