[PATCH v2] rcutorture: Reuse value read using READ_ONCE instead of re-reading it

[linke li]

rp->rtort_pipe_count is modified concurrently by rcu_torture_writer(). To
prevent a data race, reuse i which is read using READ_ONCE before instead
of re-reading it.

Signed-off-by: linke li <lilink...@qq.com>
Reviewed-by: Joel Fernandes (Google) <j...@joelfernandes.org>
---
v1 -> v2: change the patch to focus on data race in rcu_torture_pipe_update_one 
; update change log

 kernel/rcu/rcutorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 7567ca8e743c..53415121be39 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -466,7 +466,7 @@ rcu_torture_pipe_update_one(struct rcu_torture *rp)
                i = RCU_TORTURE_PIPE_LEN;
        atomic_inc(&rcu_torture_wcount[i]);
        WRITE_ONCE(rp->rtort_pipe_count, i + 1);
-       if (rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+       if (i + 1 >= RCU_TORTURE_PIPE_LEN) {
                rp->rtort_mbtest = 0;
                return true;
        }
-- 
2.39.3 (Apple Git-145)