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281 lines
9.0 KiB
C
281 lines
9.0 KiB
C
/* Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Libr \ary; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#ifndef _LOWLEVELLOCK_H
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#define _LOWLEVELLOCK_H 1
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#include <time.h>
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#include <sys/param.h>
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#include <bits/pthreadtypes.h>
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#include <atomic.h>
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#include <sysdep.h>
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#include <kernel-features.h>
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#define __NR_futex 394
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#define FUTEX_WAIT 0
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#define FUTEX_WAKE 1
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#define FUTEX_REQUEUE 3
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#define FUTEX_CMP_REQUEUE 4
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#define FUTEX_WAKE_OP 5
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#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
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#define FUTEX_LOCK_PI 6
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#define FUTEX_UNLOCK_PI 7
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#define FUTEX_TRYLOCK_PI 8
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#define FUTEX_PRIVATE_FLAG 128
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/* Values for 'private' parameter of locking macros. Yes, the
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definition seems to be backwards. But it is not. The bit will be
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reversed before passing to the system call. */
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#define LLL_PRIVATE 0
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#define LLL_SHARED FUTEX_PRIVATE_FLAG
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#if !defined NOT_IN_libc || defined IS_IN_rtld
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/* In libc.so or ld.so all futexes are private. */
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# ifdef __ASSUME_PRIVATE_FUTEX
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# define __lll_private_flag(fl, private) \
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((fl) | FUTEX_PRIVATE_FLAG)
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# else
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# define __lll_private_flag(fl, private) \
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((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
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# endif
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#else
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# ifdef __ASSUME_PRIVATE_FUTEX
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# define __lll_private_flag(fl, private) \
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(((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
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# else
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# define __lll_private_flag(fl, private) \
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(__builtin_constant_p (private) \
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? ((private) == 0 \
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? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
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: (fl)) \
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: ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
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& THREAD_GETMEM (THREAD_SELF, header.private_futex))))
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# endif
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#endif
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#define lll_futex_wait(futexp, val, private) \
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lll_futex_timed_wait (futexp, val, NULL, private)
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#define lll_futex_timed_wait(futexp, val, timespec, private) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
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__lll_private_flag (FUTEX_WAIT, private), \
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(val), (timespec)); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret; \
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})
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#define lll_futex_wake(futexp, nr, private) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
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__lll_private_flag (FUTEX_WAKE, private), \
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(nr), 0); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret; \
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})
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#define lll_robust_dead(futexv, private) \
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do \
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{ \
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int *__futexp = &(futexv); \
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atomic_or (__futexp, FUTEX_OWNER_DIED); \
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lll_futex_wake (__futexp, 1, private); \
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} \
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while (0)
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/* Returns non-zero if error happened, zero if success. */
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#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
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__lll_private_flag (FUTEX_CMP_REQUEUE, private),\
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(nr_wake), (nr_move), (mutex), (val)); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
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})
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/* Returns non-zero if error happened, zero if success. */
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#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
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({ \
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INTERNAL_SYSCALL_DECL (__err); \
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long int __ret; \
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__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
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__lll_private_flag (FUTEX_WAKE_OP, private), \
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(nr_wake), (nr_wake2), (futexp2), \
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FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
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INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
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})
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static inline int __attribute__((always_inline))
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__lll_trylock(int *futex)
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{
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return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
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}
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#define lll_trylock(lock) __lll_trylock (&(lock))
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static inline int __attribute__((always_inline))
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__lll_cond_trylock(int *futex)
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{
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return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0;
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}
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#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
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static inline int __attribute__((always_inline))
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__lll_robust_trylock(int *futex, int id)
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{
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return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0;
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}
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#define lll_robust_trylock(lock, id) \
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__lll_robust_trylock (&(lock), id)
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extern void __lll_lock_wait_private (int *futex) attribute_hidden;
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extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
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extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
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static inline void __attribute__((always_inline))
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__lll_lock(int *futex, int private)
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{
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if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
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{
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if (__builtin_constant_p (private) && private == LLL_PRIVATE)
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__lll_lock_wait_private (futex);
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else
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__lll_lock_wait (futex, private);
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}
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}
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#define lll_lock(futex, private) __lll_lock (&(futex), private)
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static inline int __attribute__ ((always_inline))
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__lll_robust_lock (int *futex, int id, int private)
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{
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int result = 0;
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if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
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result = __lll_robust_lock_wait (futex, private);
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return result;
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}
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#define lll_robust_lock(futex, id, private) \
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__lll_robust_lock (&(futex), id, private)
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static inline void __attribute__ ((always_inline))
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__lll_cond_lock (int *futex, int private)
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{
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if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
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__lll_lock_wait (futex, private);
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}
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#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
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#define lll_robust_cond_lock(futex, id, private) \
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__lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
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extern int __lll_timedlock_wait (int *futex, const struct timespec *,
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int private) attribute_hidden;
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extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
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int private) attribute_hidden;
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static inline int __attribute__ ((always_inline))
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__lll_timedlock (int *futex, const struct timespec *abstime, int private)
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{
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int result = 0;
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if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
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result = __lll_timedlock_wait (futex, abstime, private);
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return result;
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}
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#define lll_timedlock(futex, abstime, private) \
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__lll_timedlock (&(futex), abstime, private)
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static inline int __attribute__ ((always_inline))
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__lll_robust_timedlock (int *futex, const struct timespec *abstime,
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int id, int private)
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{
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int result = 0;
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if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
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result = __lll_robust_timedlock_wait (futex, abstime, private);
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return result;
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}
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#define lll_robust_timedlock(futex, abstime, id, private) \
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__lll_robust_timedlock (&(futex), abstime, id, private)
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#define __lll_unlock(futex, private) \
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(void) \
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({ int *__futex = (futex); \
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int __oldval = atomic_exchange_rel (__futex, 0); \
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if (__builtin_expect (__oldval > 1, 0)) \
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lll_futex_wake (__futex, 1, private); \
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})
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#define lll_unlock(futex, private) __lll_unlock(&(futex), private)
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#define __lll_robust_unlock(futex, private) \
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(void) \
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({ int *__futex = (futex); \
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int __oldval = atomic_exchange_rel (__futex, 0); \
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if (__builtin_expect (__oldval & FUTEX_WAITERS, 0)) \
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lll_futex_wake (__futex, 1, private); \
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})
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#define lll_robust_unlock(futex, private) \
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__lll_robust_unlock(&(futex), private)
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#define lll_islocked(futex) \
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(futex != 0)
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/* Initializers for lock. */
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#define LLL_LOCK_INITIALIZER (0)
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#define LLL_LOCK_INITIALIZER_LOCKED (1)
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/* The kernel notifies a process which uses CLONE_CLEARTID via futex
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wakeup when the clone terminates. The memory location contains the
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thread ID while the clone is running and is reset to zero
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afterwards. */
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#define lll_wait_tid(tid) \
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do { \
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__typeof (tid) __tid; \
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while ((__tid = (tid)) != 0) \
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lll_futex_wait (&(tid), __tid, LLL_SHARED); \
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} while (0)
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extern int __lll_timedwait_tid (int *, const struct timespec *)
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attribute_hidden;
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#define lll_timedwait_tid(tid, abstime) \
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({ \
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int __res = 0; \
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if ((tid) != 0) \
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__res = __lll_timedwait_tid (&(tid), (abstime)); \
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__res; \
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})
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#endif /* lowlevellock.h */
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