[PATCH v2 5/5] static_key: improve deferred inc behavior

["Radim Krčmář" <rkrcmar@redhat.com>]

We can cancel deferred static_key_slow_dec() instead of increasing
.enabled.counter.

Timer now won't fire before 'timeout' since the last increase, so this patch
further stabilizes the case of frequent switching.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
 kernel/jump_label.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index bd7ad31..9b57261 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -79,7 +79,8 @@ void static_key_slow_inc_deferred(struct static_key_deferred *key)
 	STATIC_KEY_CHECK_USE();
 	if (atomic_dec_if_positive(&key->enabled_debt) >= 0)
 		return;
-	static_key_slow_inc(&key->key);
+	if (!cancel_delayed_work(&key->work))
+		static_key_slow_inc(&key->key);
 }
 EXPORT_SYMBOL_GPL(static_key_slow_inc_deferred);
 
-- 
1.8.4.2