[PATCH 1/2] jump_label: export static_key_slow_inc/dec_cpuslocked()

From: Konstantin Khlebnikov
Date: Wed Jan 03 2018 - 15:39:22 EST


For fixing cpu_hotplug_lock recursion in tg_set_cfs_bandwidth().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
---
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();
}