rcu: Make call_rcu() lazy only when CONFIG_RCU_LAZY is enabled

Currently, regardless of whether the CONFIG_RCU_LAZY is enabled,
invoke the call_rcu() is always lazy, it also means that when
CONFIG_RCU_LAZY is disabled, invoke the call_rcu_flush() is also
lazy. therefore, this commit make call_rcu() lazy only when
CONFIG_RCU_LAZY is enabled.

Signed-off-by: Zqiang <[email protected]>
Acked-by: Joel Fernandes (Google) <[email protected]>

Author: qiangzh3

kernel/rcu/tree.c

@@ -2887,7 +2887,7 @@ EXPORT_SYMBOL_GPL(call_rcu_flush);
  */
 void call_rcu(struct rcu_head *head, rcu_callback_t func)
 {
-	return __call_rcu_common(head, func, true);
+	return __call_rcu_common(head, func, IS_ENABLED(CONFIG_RCU_LAZY));
 }
 EXPORT_SYMBOL_GPL(call_rcu);