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/* elision-unlock.c: Commit an elided pthread lock.
Copyright (C) 2015-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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/>. */
#include "pthreadP.h"
#include "lowlevellock.h"
#include "htm.h"
int
__lll_unlock_elision (int *lock, short *adapt_count, int pshared)
{
/* When the lock was free we're in a transaction. */
if (*lock == 0)
__libc_tend (0);
else
{
/* Update adapt_count in the critical section to prevent a
write-after-destroy error as mentioned in BZ 20822. The
following update of adapt_count has to be contained within
the critical region of the fall-back lock in order to not violate
the mutex destruction requirements. */
short __tmp = atomic_load_relaxed (adapt_count);
if (__tmp > 0)
atomic_store_relaxed (adapt_count, __tmp - 1);
lll_unlock ((*lock), pshared);
}
return 0;
}
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