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There are a few issues with the current virAtomic APIs - They require use of a virAtomicInt struct instead of a plain int type - Several of the methods do not implement memory barriers - The methods do not implement compiler re-ordering barriers - There is no Win32 native impl The GLib library has a nice LGPLv2+ licensed impl of atomic ops that works with GCC, Win32, or pthreads.h that addresses all these problems. The main downside to their code is that the pthreads impl uses a single global mutex, instead of a per-variable mutex. Given that it does have a Win32 impl though, we don't expect anyone to seriously use the pthread.h impl, so this downside is not significant. * .gitignore: Ignore test case * configure.ac: Check for which atomic ops impl to use * src/Makefile.am: Add viratomic.c * src/nwfilter/nwfilter_dhcpsnoop.c: Switch to new atomic ops APIs and plain int datatype * src/util/viratomic.h: inline impls of all atomic ops for GCC, Win32 and pthreads * src/util/viratomic.c: Global pthreads mutex for atomic ops * tests/viratomictest.c: Test validate to validate safety of atomic ops. Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
36 lines
1008 B
C
36 lines
1008 B
C
/*
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* viratomic.h: atomic integer operations
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*
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* Copyright (C) 2012 Red Hat, Inc.
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*
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* Based on code taken from GLib 2.32, under the LGPLv2+
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*
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* Copyright (C) 2011 Ryan Lortie
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*
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* This 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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*
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* This 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; If not, see
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* <http://www.gnu.org/licenses/>.
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*
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*/
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#include <config.h>
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#include "viratomic.h"
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#ifdef VIR_ATOMIC_OPS_PTHREAD
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pthread_mutex_t virAtomicLock = PTHREAD_MUTEX_INITIALIZER;
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#endif
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