From ce7c169dee28866539abb0e603b9a23055d30fdc Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@kernel.org>
Date: Tue, 30 Mar 2021 13:23:49 -0700
Subject: [PATCH] rcu: Remove the unused rcu_irq_exit_preempt() function

Commit 9ee01e0f69a9 ("x86/entry: Clean up idtentry_enter/exit()
leftovers") left the rcu_irq_exit_preempt() in place in order to avoid
conflicts with the -rcu tree.  Now that this change has long since hit
mainline, this commit removes the no-longer-used rcu_irq_exit_preempt()
function.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 include/linux/rcutiny.h |  1 -
 include/linux/rcutree.h |  1 -
 kernel/rcu/tree.c       | 22 ----------------------
 3 files changed, 24 deletions(-)

diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 35e0be326ffc..953e70fafe38 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -86,7 +86,6 @@ static inline void rcu_irq_enter(void) { }
 static inline void rcu_irq_exit_irqson(void) { }
 static inline void rcu_irq_enter_irqson(void) { }
 static inline void rcu_irq_exit(void) { }
-static inline void rcu_irq_exit_preempt(void) { }
 static inline void rcu_irq_exit_check_preempt(void) { }
 #define rcu_is_idle_cpu(cpu) \
 	(is_idle_task(current) && !in_nmi() && !in_irq() && !in_serving_softirq())
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index b89b54130f49..53209d669400 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -49,7 +49,6 @@ void rcu_idle_enter(void);
 void rcu_idle_exit(void);
 void rcu_irq_enter(void);
 void rcu_irq_exit(void);
-void rcu_irq_exit_preempt(void);
 void rcu_irq_enter_irqson(void);
 void rcu_irq_exit_irqson(void);
 bool rcu_is_idle_cpu(int cpu);
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8e78b2430c16..f6543b8004c0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -833,28 +833,6 @@ void noinstr rcu_irq_exit(void)
 	rcu_nmi_exit();
 }
 
-/**
- * rcu_irq_exit_preempt - Inform RCU that current CPU is exiting irq
- *			  towards in kernel preemption
- *
- * Same as rcu_irq_exit() but has a sanity check that scheduling is safe
- * from RCU point of view. Invoked from return from interrupt before kernel
- * preemption.
- */
-void rcu_irq_exit_preempt(void)
-{
-	lockdep_assert_irqs_disabled();
-	rcu_nmi_exit();
-
-	RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) <= 0,
-			 "RCU dynticks_nesting counter underflow/zero!");
-	RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) !=
-			 DYNTICK_IRQ_NONIDLE,
-			 "Bad RCU  dynticks_nmi_nesting counter\n");
-	RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
-			 "RCU in extended quiescent state!");
-}
-
 #ifdef CONFIG_PROVE_RCU
 /**
  * rcu_irq_exit_check_preempt - Validate that scheduling is possible