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/* Copyright (C) 2003-2019 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
<https://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 <errno.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_clocklock_wait (int *futex, clockid_t, int val,
const struct timespec *,
int private) attribute_hidden;
#define lll_timedwait(futex, val, clockid, abstime, private) \
__lll_clocklock_wait (futex, val, clockid, abstime, private)
static inline int
__attribute__ ((always_inline))
__lll_clocklock (int *futex, clockid_t clockid,
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))
{
do
{
int oldval = atomic_compare_and_exchange_val_24_acq (futex, val, 1);
if (oldval != 0)
{
result = __lll_clocklock_wait (futex, 2, clockid, abstime,
private);
if (result == EINVAL || result == ETIMEDOUT)
break;
}
}
while (atomic_compare_and_exchange_val_24_acq (futex, val, 0) != 0);
}
return result;
}
#define lll_clocklock(futex, clockid, abstime, private) \
__lll_clocklock (&(futex), clockid, 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)
#endif /* lowlevellock.h */
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