Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 9146558..18b1ed9 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -1,26 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  * Read-Copy Update mechanism for mutual exclusion (tree-based version)
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
  * Copyright IBM Corporation, 2008
  *
  * Author: Dipankar Sarma <dipankar@in.ibm.com>
- *	   Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
+ *	   Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical algorithm
  *
- * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
+ * Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
  * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
  *
  * For detailed explanation of Read-Copy Update mechanism see -
@@ -30,6 +17,7 @@
 #ifndef __LINUX_RCUTREE_H
 #define __LINUX_RCUTREE_H
 
+void rcu_softirq_qs(void);
 void rcu_note_context_switch(bool preempt);
 int rcu_needs_cpu(u64 basem, u64 *nextevt);
 void rcu_cpu_stall_reset(void);
@@ -44,41 +32,13 @@
 	rcu_note_context_switch(false);
 }
 
-void synchronize_rcu_bh(void);
-void synchronize_sched_expedited(void);
 void synchronize_rcu_expedited(void);
-
 void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
 
-/**
- * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
- *
- * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
- * approach to force the grace period to end quickly.  This consumes
- * significant time on all CPUs and is unfriendly to real-time workloads,
- * so is thus not recommended for any sort of common-case code.  In fact,
- * if you are using synchronize_rcu_bh_expedited() in a loop, please
- * restructure your code to batch your updates, and then use a single
- * synchronize_rcu_bh() instead.
- *
- * Note that it is illegal to call this function while holding any lock
- * that is acquired by a CPU-hotplug notifier.  And yes, it is also illegal
- * to call this function from a CPU-hotplug notifier.  Failing to observe
- * these restriction will result in deadlock.
- */
-static inline void synchronize_rcu_bh_expedited(void)
-{
-	synchronize_sched_expedited();
-}
-
 void rcu_barrier(void);
-void rcu_barrier_bh(void);
-void rcu_barrier_sched(void);
 bool rcu_eqs_special_set(int cpu);
 unsigned long get_state_synchronize_rcu(void);
 void cond_synchronize_rcu(unsigned long oldstate);
-unsigned long get_state_synchronize_sched(void);
-void cond_synchronize_sched(unsigned long oldstate);
 
 void rcu_idle_enter(void);
 void rcu_idle_exit(void);
@@ -93,7 +53,9 @@
 extern int rcu_scheduler_active __read_mostly;
 void rcu_end_inkernel_boot(void);
 bool rcu_is_watching(void);
+#ifndef CONFIG_PREEMPTION
 void rcu_all_qs(void);
+#endif
 
 /* RCUtree hotplug events */
 int rcutree_prepare_cpu(unsigned int cpu);