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From ce74a620bf9e1a40b7ba06d35160e20633a4d8bb Mon Sep 17 00:00:00 2001
From: Catalin Enache <catalin.enache@windriver.com>
Date: Fri, 7 Jul 2017 13:11:16 +0300
Subject: [PATCH 1/6] Add atomic_exchange_relaxed.
* include/atomic.h (atomic_exchange_relaxed): New
Upstream-Status: Backport
Author: Torvald Riegel <triegel@redhat.com>
Signed-off-by: Catalin Enache <catalin.enache@windriver.com>
---
ChangeLog | 4 ++++
include/atomic.h | 9 +++++++++
2 files changed, 13 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 0fbda90..cb87279 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2016-08-05 Torvald Riegel <triegel@redhat.com>
+
+ * include/atomic.h (atomic_exchange_relaxed): New.
+
2016-01-28 Carlos O'Donell <carlos@redhat.com>
Alexey Makhalov <amakhalov@vmware.com>
Florian Weimer <fweimer@redhat.com>
diff --git a/include/atomic.h b/include/atomic.h
index ad3db25..129ee24 100644
--- a/include/atomic.h
+++ b/include/atomic.h
@@ -588,6 +588,9 @@ void __atomic_link_error (void);
__atomic_compare_exchange_n ((mem), (expected), (desired), 1, \
__ATOMIC_RELEASE, __ATOMIC_RELAXED); })
+# define atomic_exchange_relaxed(mem, desired) \
+ ({ __atomic_check_size((mem)); \
+ __atomic_exchange_n ((mem), (desired), __ATOMIC_RELAXED); })
# define atomic_exchange_acquire(mem, desired) \
({ __atomic_check_size((mem)); \
__atomic_exchange_n ((mem), (desired), __ATOMIC_ACQUIRE); })
@@ -684,6 +687,12 @@ void __atomic_link_error (void);
*(expected) == __atg103_expected; })
# endif
+/* XXX Fall back to acquire MO because archs do not define a weaker
+ atomic_exchange. */
+# ifndef atomic_exchange_relaxed
+# define atomic_exchange_relaxed(mem, val) \
+ atomic_exchange_acq ((mem), (val))
+# endif
# ifndef atomic_exchange_acquire
# define atomic_exchange_acquire(mem, val) \
atomic_exchange_acq ((mem), (val))
--
2.10.2
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