[PATCH v2 3/3] rcu_qs: Use READ_ONCE() AND WRITE_ONCE() for shared variable rcu_gp_ctr

[Junchang Wang <junchangwang@xxxxxxxxx>]

Signed-off-by: Junchang Wang <junchangwang@xxxxxxxxx>
Reviewed-by: Akira Yokosawa <akiyks@xxxxxxxxx>
---
 CodeSamples/defer/rcu_qs.c | 2 +-
 CodeSamples/defer/rcu_qs.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CodeSamples/defer/rcu_qs.c b/CodeSamples/defer/rcu_qs.c
index 27e45f7..f3d0cd6 100644
--- a/CodeSamples/defer/rcu_qs.c
+++ b/CodeSamples/defer/rcu_qs.c
@@ -41,7 +41,7 @@ void synchronize_rcu(void)
 
 	/* Advance to a new grace-period number, enforce ordering. */
 
-	rcu_gp_ctr += 2;
+	WRITE_ONCE(rcu_gp_ctr, rcu_gp_ctr + 2);
 	smp_mb();
 
 	/*
diff --git a/CodeSamples/defer/rcu_qs.h b/CodeSamples/defer/rcu_qs.h
index 3bb45a4..d8be43e 100644
--- a/CodeSamples/defer/rcu_qs.h
+++ b/CodeSamples/defer/rcu_qs.h
@@ -59,14 +59,14 @@ static void rcu_read_unlock(void)
 static void rcu_quiescent_state(void)
 {
 	smp_mb();
-	__get_thread_var(rcu_reader_qs_gp) = ACCESS_ONCE(rcu_gp_ctr) + 1;
+	__get_thread_var(rcu_reader_qs_gp) = READ_ONCE(rcu_gp_ctr) + 1;
 	smp_mb();
 }
 
 static void rcu_thread_offline(void)
 {
 	smp_mb();
-	__get_thread_var(rcu_reader_qs_gp) = ACCESS_ONCE(rcu_gp_ctr);
+	__get_thread_var(rcu_reader_qs_gp) = READ_ONCE(rcu_gp_ctr);
 	smp_mb();
 }
 
-- 
2.7.4