From 89e005ff8a02ef206e4e7755ec7d37e45262cc2d Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paul.mckenney@linaro.org>
Date: Wed, 11 May 2011 05:33:33 -0700
Subject: [PATCH] atomic: Add atomic_or()
An atomic_or() function is needed by TREE_RCU to avoid deadlock, so
add a generic version.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/atomic.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 96c038e43d667..ee456c79b0e67 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -34,4 +34,17 @@ static inline int atomic_inc_not_zero_hint(atomic_t *v, int hint)
}
#endif
+#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
+static inline void atomic_or(int i, atomic_t *v)
+{
+ int old;
+ int new;
+
+ do {
+ old = atomic_read(v);
+ new = old | i;
+ } while (atomic_cmpxchg(v, old, new) != old);
+}
+#endif /* #ifndef CONFIG_ARCH_HAS_ATOMIC_OR */
+
#endif /* _LINUX_ATOMIC_H */
--
2.39.5