[PATCH RT 09/19] rcu: Don't allow to change rcu_normal_after_boot on RT

[zanussi]

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

v4.14.137-rt65-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------


[ Upstream commit c6c058c10577815a2491ce661876cff00a4c3b15 ]

On RT rcu_normal_after_boot is enabled by default.
Don't allow to disable it on RT because the "expedited rcu" would
introduce latency spikes.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx>
---
 kernel/rcu/update.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 2006a09680aa..307592810f6b 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -67,7 +67,9 @@ module_param(rcu_expedited, int, 0);
 extern int rcu_normal; /* from sysctl */
 module_param(rcu_normal, int, 0);
 static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
+#ifndef CONFIG_PREEMPT_RT_FULL
 module_param(rcu_normal_after_boot, int, 0);
+#endif
 #endif /* #ifndef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
-- 
2.14.1