[RFC][PATCH] rcu: Use WRITE_ONCE in RCU_INIT_POINTER

From: Peter Zijlstra
Date: Tue Jun 02 2015 - 11:27:06 EST



For the paranoid amongst us GCC would be in its right to use byte stores
to write our NULL value, tell it not to do that.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 33a056bb886f..e173847b6543 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1046,7 +1046,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
#define RCU_INIT_POINTER(p, v) \
do { \
rcu_dereference_sparse(p, __rcu); \
- p = RCU_INITIALIZER(v); \
+ WRITE_ONCE(p, RCU_INITIALIZER(v)); \
} while (0)

/**
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