49 lines
1.8 KiB
C
49 lines
1.8 KiB
C
/* Copyright (C) 2003-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
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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 Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <sysdep.h>
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#include <futex-internal.h>
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#include <pthread.h>
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#include <pthreadP.h>
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#include <stap-probe.h>
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#include "pthread_rwlock_common.c"
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/* See pthread_rwlock_common.c for an overview. */
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int
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__pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
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{
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LIBC_PROBE (rwlock_unlock, 1, rwlock);
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/* We distinguish between having acquired a read vs. a write lock by looking
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at the writer TID. If it's equal to our TID, we must be the writer
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because nobody else can have stored this value. Also, if we are a
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reader, we will read from the wrunlock store with value 0 by the most
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recent writer because that writer happens-before us. */
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if (atomic_load_relaxed (&rwlock->__data.__cur_writer)
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== THREAD_GETMEM (THREAD_SELF, tid))
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__pthread_rwlock_wrunlock (rwlock);
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else
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__pthread_rwlock_rdunlock (rwlock);
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return 0;
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}
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weak_alias (__pthread_rwlock_unlock, pthread_rwlock_unlock)
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hidden_def (__pthread_rwlock_unlock)
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