linux-kernel - [PATCH 1/2] jump_label: export static_key_slow_inc/dec

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Message-ID: <151501139053.928921.10437479983023205360.stgit@buzz>
Date:   Wed, 03 Jan 2018 23:29:50 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 1/2] jump_label: export static_key_slow_inc/dec_cpuslocked()

For fixing cpu_hotplug_lock recursion in tg_set_cfs_bandwidth().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 include/linux/jump_label.h |   12 ++++++++++++
 kernel/jump_label.c        |   18 +++++++++++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index c7b368c734af..db10e6a9d315 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -160,6 +160,8 @@ extern void arch_jump_label_transform_static(struct jump_entry *entry,
 extern int jump_label_text_reserved(void *start, void *end);
 extern void static_key_slow_inc(struct static_key *key);
 extern void static_key_slow_dec(struct static_key *key);
+extern void static_key_slow_inc_cpuslocked(struct static_key *key);
+extern void static_key_slow_dec_cpuslocked(struct static_key *key);
 extern void jump_label_apply_nops(struct module *mod);
 extern int static_key_count(struct static_key *key);
 extern void static_key_enable(struct static_key *key);
@@ -222,6 +224,16 @@ static inline void static_key_slow_dec(struct static_key *key)
 	atomic_dec(&key->enabled);
 }
 
+static inline void static_key_slow_inc_cpuslocked(struct static_key *key)
+{
+	static_key_slow_inc(key);
+}
+
+static inline void static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+	static_key_slow_dec(key);
+}
+
 static inline int jump_label_text_reserved(void *start, void *end)
 {
 	return 0;
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 8594d24e4adc..9813895231cc 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -79,7 +79,7 @@ int static_key_count(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_count);
 
-static void static_key_slow_inc_cpuslocked(struct static_key *key)
+void static_key_slow_inc_cpuslocked(struct static_key *key)
 {
 	int v, v1;
 
@@ -117,6 +117,7 @@ static void static_key_slow_inc_cpuslocked(struct static_key *key)
 	}
 	jump_label_unlock();
 }
+EXPORT_SYMBOL_GPL(static_key_slow_inc_cpuslocked);
 
 void static_key_slow_inc(struct static_key *key)
 {
@@ -180,9 +181,9 @@ void static_key_disable(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_disable);
 
-static void static_key_slow_dec_cpuslocked(struct static_key *key,
-					   unsigned long rate_limit,
-					   struct delayed_work *work)
+static void __static_key_slow_dec_cpuslocked(struct static_key *key,
+					     unsigned long rate_limit,
+					     struct delayed_work *work)
 {
 	/*
 	 * The negative count check is valid even when a negative
@@ -206,12 +207,19 @@ static void static_key_slow_dec_cpuslocked(struct static_key *key,
 	jump_label_unlock();
 }
 
+void static_key_slow_dec_cpuslocked(struct static_key *key)
+{
+	STATIC_KEY_CHECK_USE(key);
+	__static_key_slow_dec_cpuslocked(key, 0, NULL);
+}
+EXPORT_SYMBOL_GPL(static_key_slow_dec_cpuslocked);
+
 static void __static_key_slow_dec(struct static_key *key,
 				  unsigned long rate_limit,
 				  struct delayed_work *work)
 {
 	cpus_read_lock();
-	static_key_slow_dec_cpuslocked(key, rate_limit, work);
+	__static_key_slow_dec_cpuslocked(key, rate_limit, work);
 	cpus_read_unlock();
 }