[PATCH rcu 2/7] rcu: Move rcu_data.cpu_no_qs.b.exp reset to rcu_export_exp_rdp()

["Paul E. McKenney" <paulmck@kernel.org>]

From: Frederic Weisbecker <frederic@kernel.org>

On non-preemptible RCU, move clearing of the rcu_data structure's
->cpu_no_qs.b.exp filed to the actual expedited quiescent state report
function, matching hw preemptible RCU handles the ->exp_deferred_qs field.

This prepares for removing ->exp_deferred_qs in favor of ->cpu_no_qs.b.exp
for both preemptible and non-preemptible RCU.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree_exp.h    | 1 +
 kernel/rcu/tree_plugin.h | 6 ++----
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index f3947c49eee71..6c6eb32203852 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -256,6 +256,7 @@ static void rcu_report_exp_cpu_mult(struct rcu_node *rnp,
 static void rcu_report_exp_rdp(struct rcu_data *rdp)
 {
 	WRITE_ONCE(rdp->exp_deferred_qs, false);
+	WRITE_ONCE(rdp->cpu_no_qs.b.exp, false);
 	rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);
 }
 
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 983619ba86656..1e4b4e7630735 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -849,10 +849,8 @@ static void rcu_qs(void)
 	trace_rcu_grace_period(TPS("rcu_sched"),
 			       __this_cpu_read(rcu_data.gp_seq), TPS("cpuqs"));
 	__this_cpu_write(rcu_data.cpu_no_qs.b.norm, false);
-	if (!__this_cpu_read(rcu_data.cpu_no_qs.b.exp))
-		return;
-	__this_cpu_write(rcu_data.cpu_no_qs.b.exp, false);
-	rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
+	if (__this_cpu_read(rcu_data.cpu_no_qs.b.exp))
+		rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
 }
 
 /*
-- 
2.31.1.189.g2e36527f23