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Subject[PATCHv2 1/2] jump_label: Provide static_key_[enable|/slow_inc]_cpuslocked()
Date
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

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

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: jbaron@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
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