[PATCH v2 2/3] rcu_nest: 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_nest.c | 2 +-
 CodeSamples/defer/rcu_nest.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/CodeSamples/defer/rcu_nest.c b/CodeSamples/defer/rcu_nest.c
index 64e4087..733b01a 100644
--- a/CodeSamples/defer/rcu_nest.c
+++ b/CodeSamples/defer/rcu_nest.c
@@ -35,7 +35,7 @@ void synchronize_rcu(void)
 
 	/* Advance to a new grace-period number, enforce ordering. */
 
-	rcu_gp_ctr += RCU_GP_CTR_BOTTOM_BIT;
+	WRITE_ONCE(rcu_gp_ctr, rcu_gp_ctr + RCU_GP_CTR_BOTTOM_BIT);
 	smp_mb();
 
 	/*
diff --git a/CodeSamples/defer/rcu_nest.h b/CodeSamples/defer/rcu_nest.h
index bcc4cde..64d9679 100644
--- a/CodeSamples/defer/rcu_nest.h
+++ b/CodeSamples/defer/rcu_nest.h
@@ -52,7 +52,7 @@ static void rcu_read_lock(void)
 retry:
 	tmp = *rrgp;
 	if ((tmp & RCU_GP_CTR_NEST_MASK) == 0)
-		tmp = rcu_gp_ctr;
+		tmp = READ_ONCE(rcu_gp_ctr);
 	tmp++;
 	*rrgp = tmp;
 	smp_mb();
-- 
2.7.4