From: Frederic Weisbecker <frederic@xxxxxxxxxx>
It's more convenient to benefit from the fallthrough feature of
switch / case to handle the timer state machine. Also a new state is
about to be added that will take advantage of it.
No intended functional change.
Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/tree_nocb.h | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index 2605dd234a13c..0923d60c5a338 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -271,22 +271,35 @@ static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype,
raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
- /*
- * Bypass wakeup overrides previous deferments. In case of
- * callback storms, no need to wake up too early.
- */
- if (waketype == RCU_NOCB_WAKE_LAZY &&
- rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_NOT) {
- mod_timer(&rdp_gp->nocb_timer, jiffies + rcu_get_jiffies_lazy_flush());
- WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
- } else if (waketype == RCU_NOCB_WAKE_BYPASS) {
+ switch (waketype) {
+ case RCU_NOCB_WAKE_BYPASS:
+ /*
+ * Bypass wakeup overrides previous deferments. In case of
+ * callback storms, no need to wake up too early.
+ */
mod_timer(&rdp_gp->nocb_timer, jiffies + 2);
WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
- } else {
+ break;
+ case RCU_NOCB_WAKE_LAZY:
+ if (rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_NOT) {
+ mod_timer(&rdp_gp->nocb_timer, jiffies + rcu_get_jiffies_lazy_flush());
+ WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+ }
+ /*
+ * If the timer is already armed, a non-lazy enqueue may have happened
+ * in-between. Don't delay it and fall-through.
+ */
+ break;
+ case RCU_NOCB_WAKE:
+ fallthrough;
+ case RCU_NOCB_WAKE_FORCE:
if (rdp_gp->nocb_defer_wakeup < RCU_NOCB_WAKE)
mod_timer(&rdp_gp->nocb_timer, jiffies + 1);
if (rdp_gp->nocb_defer_wakeup < waketype)
WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+ break;
+ default:
+ WARN_ON_ONCE(1);
}
raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
--
2.40.1
