[tip: core/rcu] kvfree_rcu: Update "monitor_todo" once a batch is started

[tip: core/rcu] kvfree_rcu: Update "monitor_todo" once a batch is started

[tip-bot2 for Uladzislau Rezki (Sony)]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     dd28c9f057ad099f6221829053e48f331e6f0b7f
Gitweb:        https://git.kernel.org/tip/dd28c9f057ad099f6221829053e48f331e6f0b7f
Author:        Uladzislau Rezki (Sony) <urezki@gmail.com>
AuthorDate:    Thu, 15 Apr 2021 19:19:59 +02:00
Committer:     Paul E. McKenney <paulmck@kernel.org>
CommitterDate: Mon, 10 May 2021 16:00:48 -07:00

kvfree_rcu: Update "monitor_todo" once a batch is started

Before attempting to start a new batch the "monitor_todo" variable is
set to "false" and set back to "true" when a previous RCU batch is still
in progress.  This is at best confusing.

Thus change this variable to "false" only when a new batch has been
successfully queued, otherwise, just leave it be.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/tree.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e86f32d..1ae5f88 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3442,15 +3442,14 @@ static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,
 					  unsigned long flags)
 {
 	// Attempt to start a new batch.
-	krcp->monitor_todo = false;
 	if (queue_kfree_rcu_work(krcp)) {
 		// Success! Our job is done here.
+		krcp->monitor_todo = false;
 		raw_spin_unlock_irqrestore(&krcp->lock, flags);
 		return;
 	}
 
 	// Previous RCU batch still in progress, try again later.
-	krcp->monitor_todo = true;
 	schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
 	raw_spin_unlock_irqrestore(&krcp->lock, flags);
 }