glibc/nptl/pthread_rwlock_unlock.c
Florian Weimer eb29dcde31 nptl: Move rwlock functions with forwarders into libc
The forwarders were only used internally, so new symbol versions
are needed.  All symbols are moved at once because the forwarders
are no-ops if libpthread is not loaded, leading to inconsistencies
in case of a partial migration.

The symbols __pthread_rwlock_rdlock, __pthread_rwlock_unlock,
__pthread_rwlock_wrlock, pthread_rwlock_rdlock,
pthread_rwlock_unlock, pthread_rwlock_wrlock have been moved using
scripts/move-symbol-to-libc.py.

The __ symbol variants are turned into compat symbols, which is why they
do not receive a GLIBC_2.34 version.
2021-04-21 19:49:51 +02:00

59 lines
2.2 KiB
C

/* Copyright (C) 2003-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.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/>. */
#include <errno.h>
#include <sysdep.h>
#include <futex-internal.h>
#include <pthread.h>
#include <pthreadP.h>
#include <stap-probe.h>
#include "pthread_rwlock_common.c"
/* See pthread_rwlock_common.c for an overview. */
int
___pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
{
LIBC_PROBE (rwlock_unlock, 1, rwlock);
/* We distinguish between having acquired a read vs. a write lock by looking
at the writer TID. If it's equal to our TID, we must be the writer
because nobody else can have stored this value. Also, if we are a
reader, we will read from the wrunlock store with value 0 by the most
recent writer because that writer happens-before us. */
if (atomic_load_relaxed (&rwlock->__data.__cur_writer)
== THREAD_GETMEM (THREAD_SELF, tid))
__pthread_rwlock_wrunlock (rwlock);
else
__pthread_rwlock_rdunlock (rwlock);
return 0;
}
versioned_symbol (libc, ___pthread_rwlock_unlock, pthread_rwlock_unlock,
GLIBC_2_34);
strong_alias (___pthread_rwlock_unlock, __pthread_rwlock_unlock)
libc_hidden_ver (___pthread_rwlock_unlock, __pthread_rwlock_unlock)
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_1, GLIBC_2_34)
compat_symbol (libpthread, ___pthread_rwlock_unlock, pthread_rwlock_unlock,
GLIBC_2_1);
#endif
#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34)
compat_symbol (libpthread, ___pthread_rwlock_unlock, __pthread_rwlock_unlock,
GLIBC_2_2);
#endif