From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 24 Jul 2015 13:03:40 +0000 (+0200)
Subject: locking/static_keys: Add static_key_{en,dis}able() helpers
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=e33886b38cc82a9fc3b2d655dfc7f50467594138;p=openwrt%2Fstaging%2Fblogic.git

locking/static_keys: Add static_key_{en,dis}able() helpers

Add two helpers to make it easier to treat the refcount as boolean.

Suggested-by: Jason Baron <jasonbaron0@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 0ddb208b8449..65f0ebac63cf 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -198,6 +198,26 @@ static inline bool static_key_enabled(struct static_key *key)
 	return static_key_count(key) > 0;
 }
 
+static inline void static_key_enable(struct static_key *key)
+{
+	int count = static_key_count(key);
+
+	WARN_ON_ONCE(count < 0 || count > 1);
+
+	if (!count)
+		static_key_slow_inc(key);
+}
+
+static inline void static_key_disable(struct static_key *key)
+{
+	int count = static_key_count(key);
+
+	WARN_ON_ONCE(count < 0 || count > 1);
+
+	if (count)
+		static_key_slow_dec(key);
+}
+
 #endif	/* _LINUX_JUMP_LABEL_H */
 
 #endif /* __ASSEMBLY__ */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 78b4bad10081..66ae8baf42fe 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -164,14 +164,12 @@ struct static_key sched_feat_keys[__SCHED_FEAT_NR] = {
 
 static void sched_feat_disable(int i)
 {
-	if (static_key_enabled(&sched_feat_keys[i]))
-		static_key_slow_dec(&sched_feat_keys[i]);
+	static_key_disable(&sched_feat_keys[i]);
 }
 
 static void sched_feat_enable(int i)
 {
-	if (!static_key_enabled(&sched_feat_keys[i]))
-		static_key_slow_inc(&sched_feat_keys[i]);
+	static_key_enable(&sched_feat_keys[i]);
 }
 #else
 static void sched_feat_disable(int i) { };