linux/debian/patches-rt/0110-sched-Do-not-account-rcu_preempt_depth-on-RT-in-migh.patch

From c1079fcb888f7bbdef9e2d4cc03c1d4eb26e4dd5 Mon Sep 17 00:00:00 2001
Message-Id: <c1079fcb888f7bbdef9e2d4cc03c1d4eb26e4dd5.1601675152.git.zanussi@kernel.org>
In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
From: Thomas Gleixner <tglx@linutronix.de>
Date: Tue, 7 Jun 2011 09:19:06 +0200
Subject: [PATCH 110/333] sched: Do not account rcu_preempt_depth on RT in
 might_sleep()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz

RT changes the rcu_preempt_depth semantics, so we cannot check for it
in might_sleep().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rcupdate.h | 7 +++++++
 kernel/sched/core.c      | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 68cbe111420b..027c58cdbb6e 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -73,6 +73,11 @@ void synchronize_rcu(void);
  * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
  */
 #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
+#ifndef CONFIG_PREEMPT_RT_FULL
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+#else
+static inline int sched_rcu_preempt_depth(void) { return 0; }
+#endif
 
 #else /* #ifdef CONFIG_PREEMPT_RCU */
 
@@ -96,6 +101,8 @@ static inline int rcu_preempt_depth(void)
 	return 0;
 }
 
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
 /* Internal to kernel */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 53d9f8927619..2aa1d2a9ee5e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6193,7 +6193,7 @@ void __init sched_init(void)
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 static inline int preempt_count_equals(int preempt_offset)
 {
-	int nested = preempt_count() + rcu_preempt_depth();
+	int nested = preempt_count() + sched_rcu_preempt_depth();
 
 	return (nested == preempt_offset);
 }
-- 
2.17.1