From: Peter Zijlstra <[email protected]>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit e33886b38cc82a9fc3b2d655dfc7f50467594138 upstream.

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

[js] do not involve WARN_ON_ONCE as it causes build failures

Suggested-by: Jason Baron <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Jiri Slaby <[email protected]>
---
 include/linux/jump_label.h | 16 ++++++++++++++++
 kernel/sched/core.c        |  6 ++----
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 9216e465289a..6fdea8105f45 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -188,4 +188,20 @@ 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);
+
+       if (!count)
+               static_key_slow_inc(key);
+}
+
+static inline void static_key_disable(struct static_key *key)
+{
+       int count = static_key_count(key);
+
+       if (count)
+               static_key_slow_dec(key);
+}
+
 #endif /* _LINUX_JUMP_LABEL_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 426193802b1f..602b6c08c47d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -179,14 +179,12 @@ 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) { };
-- 
2.12.2

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