[PATCHv3 1/2] jump_label: Provide static_key_[enable|/slow_inc]_cpuslocked()

[Mark Rutland]

From: Sebastian Andrzej Siewior <bige...@linutronix.de>

Provide static_key_[enable|slow_inc]_cpuslocked() variant that
don't take cpu_hotplug_lock().

Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Signed-off-by: Mark Rutland <mark.rutl...@arm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Sebastian Siewior <bige...@linutronix.de>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: jba...@akamai.com
---
 include/linux/jump_label.h |  7 +++++++
 kernel/jump_label.c        | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index d7b17d1..c80d8b1 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -164,6 +164,7 @@ extern void arch_jump_label_transform_static(struct 
jump_entry *entry,
 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);
+extern void static_key_enable_cpuslocked(struct static_key *key);
 extern void static_key_disable(struct static_key *key);
 extern void static_key_disable_cpuslocked(struct static_key *key);
 
@@ -252,6 +253,11 @@ static inline void static_key_enable(struct static_key 
*key)
                static_key_slow_inc(key);
 }
 
+static inline void static_key_enable_cpuslocked(struct static_key *key)
+{
+       static_key_enable(key);
+}
+
 static inline void static_key_disable(struct static_key *key)
 {
        int count = static_key_count(key);
@@ -429,6 +435,7 @@ struct static_key_false {
  */
 
 #define static_branch_enable(x)                        
static_key_enable(&(x)->key)
+#define static_branch_enable_cpuslocked(x)     
static_key_enable_cpuslocked(&(x)->key)
 #define static_branch_disable(x)               static_key_disable(&(x)->key)
 #define static_branch_disable_cpuslocked(x)    
static_key_disable_cpuslocked(&(x)->key)
 
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index d71124e..6343f4c 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -90,6 +90,16 @@ void static_key_enable(struct static_key *key)
 }
 EXPORT_SYMBOL_GPL(static_key_enable);
 
+void static_key_enable_cpuslocked(struct static_key *key)
+{
+       int count = static_key_count(key);
+
+       WARN_ON_ONCE(count < 0 || count > 1);
+
+       if (!count)
+               static_key_slow_inc_cpuslocked(key);
+}
+
 void static_key_disable(struct static_key *key)
 {
        int count = static_key_count(key);
-- 
1.9.1