[PATCH 09/13] rcu/nocb: Cancel nocb_timer upon nocb_gp wakeup

[Frederic Weisbecker]

As we wake up in nocb_gp_wait(), there is no need to keep the nocb_timer
around as we are going to go through the whole rdp list again. Any update
performed before the timer was armed will now be visible after the
nocb_gp_lock acquire.

Signed-off-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Neeraj Upadhyay <neeraju@xxxxxxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
---
 kernel/rcu/tree_plugin.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 0fdf0223f08f..b62ad79bbda5 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2221,6 +2221,10 @@ static void nocb_gp_wait(struct rcu_data *my_rdp)
 		raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
 		if (bypass)
 			del_timer(&my_rdp->nocb_bypass_timer);
+		if (my_rdp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) {
+			WRITE_ONCE(my_rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+			del_timer(&my_rdp->nocb_timer);
+		}
 		WRITE_ONCE(my_rdp->nocb_gp_sleep, true);
 		raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
 	}
-- 
2.25.1