/* Copyright (C) 2003-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#ifndef _LOWLEVELLOCK_H

#define _LOWLEVELLOCK_H	1

#include <time.h>

#include <sys/param.h>

#include <bits/pthreadtypes.h>

#include <atomic.h>

#include <kernel-features.h>

#include <lowlevellock-futex.h>

static inline int

__attribute__ ((always_inline))

__lll_trylock (int *futex)

{

  return atomic_compare_and_exchange_val_24_acq (futex, 1, 0) != 0;

}

#define lll_trylock(futex) __lll_trylock (&(futex))

static inline int

__attribute__ ((always_inline))

__lll_cond_trylock (int *futex)

{

  return atomic_compare_and_exchange_val_24_acq (futex, 2, 0) != 0;

}

#define lll_cond_trylock(futex) __lll_cond_trylock (&(futex))

extern void __lll_lock_wait_private (int *futex) attribute_hidden;

extern void __lll_lock_wait (int *futex, int private) attribute_hidden;

static inline void

__attribute__ ((always_inline))

__lll_lock (int *futex, int private)

{

  int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);

  if (__glibc_unlikely (val != 0))

    {

      if (__builtin_constant_p (private) && private == LLL_PRIVATE)

	__lll_lock_wait_private (futex);

      else

	__lll_lock_wait (futex, private);

    }

}

#define lll_lock(futex, private) __lll_lock (&(futex), private)

static inline void

__attribute__ ((always_inline))

__lll_cond_lock (int *futex, int private)

{

  int val = atomic_compare_and_exchange_val_24_acq (futex, 2, 0);

  if (__glibc_unlikely (val != 0))

    __lll_lock_wait (futex, private);

}

#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)

extern int __lll_timedlock_wait (int *futex, const struct timespec *,

				 int private) attribute_hidden;

static inline int

__attribute__ ((always_inline))

__lll_timedlock (int *futex, const struct timespec *abstime, int private)

{

  int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);

  int result = 0;

  if (__glibc_unlikely (val != 0))

    result = __lll_timedlock_wait (futex, abstime, private);

  return result;

}

#define lll_timedlock(futex, abstime, private) \

  __lll_timedlock (&(futex), abstime, private)

#define lll_unlock(lock, private) \

  ((void) ({								      \

    int *__futex = &(lock);						      \

    int __private = (private);						      \

    int __val = atomic_exchange_24_rel (__futex, 0);			      \

    if (__glibc_unlikely (__val > 1))					      \

      lll_futex_wake (__futex, 1, __private);				      \

  }))

#define lll_islocked(futex) \

  (futex != 0)

/* Initializers for lock.  */

#define LLL_LOCK_INITIALIZER		(0)

#define LLL_LOCK_INITIALIZER_LOCKED	(1)

/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex

   wakeup when the clone terminates.  The memory location contains the

   thread ID while the clone is running and is reset to zero

   afterwards.	*/

#define lll_wait_tid(tid) \

  do							\

    {							\

      __typeof (tid) __tid;				\

      while ((__tid = (tid)) != 0)			\

	lll_futex_wait (&(tid), __tid, LLL_SHARED);	\

    }							\

  while (0)

extern int __lll_timedwait_tid (int *, const struct timespec *)

     attribute_hidden;

#define lll_timedwait_tid(tid, abstime) \

  ({							\

    int __res = 0;					\

    if ((tid) != 0)					\

      __res = __lll_timedwait_tid (&(tid), (abstime));	\

    __res;						\

  })

#endif	/* lowlevellock.h */