rcu: Replace smp_wmb() with smp_store_release() for stall check

This commit gets rid of the smp_wmb() in record_gp_stall_check_time()
in favor of an smp_store_release().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a4277c1..439228b 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1246,9 +1246,9 @@ static void record_gp_stall_check_time(struct rcu_state *rsp)
        unsigned long j1;
 
        rsp->gp_start = j;
-       smp_wmb(); /* Record start time before stall time. */
        j1 = rcu_jiffies_till_stall_check();
-       WRITE_ONCE(rsp->jiffies_stall, j + j1);
+       /* Record ->gp_start before ->jiffies_stall. */
+       smp_store_release(&rsp->jiffies_stall, j + j1); /* ^^^ */
        rsp->jiffies_resched = j + j1 / 2;
        rsp->n_force_qs_gpstart = READ_ONCE(rsp->n_force_qs);
 }