From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Fri, 10 Feb 2017 22:50:46 +0000 (-0800)
Subject: srcu: Allow early boot use of synchronize_srcu()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b5eaeaa509d30812049f9e1c05446d564e91616b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

srcu: Allow early boot use of synchronize_srcu()

This commit checks for pre-scheduler state, and if that early in the
boot process, synchronize_srcu() and friends are no-ops.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---

diff --git a/kernel/rcu/srcu.c b/kernel/rcu/srcu.c
index e6da9fc1f0e9..7e7ecaa50dc5 100644
--- a/kernel/rcu/srcu.c
+++ b/kernel/rcu/srcu.c
@@ -417,6 +417,8 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
 			 lock_is_held(&rcu_sched_lock_map),
 			 "Illegal synchronize_srcu() in same-type SRCU (or in RCU) read-side critical section");
 
+	if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
+		return;
 	might_sleep();
 	init_completion(&rcu.completion);