From: Paul E. McKenney <paul.mckenney@linaro.org>
Date: Wed, 11 May 2011 12:33:33 +0000 (-0700)
Subject: atomic: Add atomic_or()
X-Git-Tag: v3.0-rc1~24^2~3
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=55c2945aa9d4d907ec5ca4f6a4e30ae908d8d30d;p=karo-tx-linux.git

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>
---

diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 96c038e43d66..ee456c79b0e6 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 */