[PATCH 3/4] rcu: Move rcu_data.cpu_no_qs.b.exp reset to rcu_export_exp_rdp()

From: Frederic Weisbecker
Date: Thu Sep 16 2021 - 08:11:13 EST


On non-preemptible RCU, move clearing of rcu_data.cpu_no_qs.b.exp to
the actual expedited quiescent state report function, in a similar way
to preemptible RCU dealing with rdp->exp_deferred_qs.

This prepares to remove the exp_deferred_qs field and generalize the use
of cpu_no_qs.b.exp to both preemptible and non-preemptible RCU.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
---
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 4266610b4587..992f9475d243 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)
{
rdp->exp_deferred_qs = false;
+ 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 4c9aeabec242..b20634fde43d 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));
}

/*
--
2.25.1