locking/static_key: Add support for deferred static branches

Add deferred static branches.  We can't unfortunately use the
nice trick of encapsulating the entire structure in true/false
variants, because the inside has to be either struct static_key_true
or struct static_key_false.  Use defines to pass the appropriate
members to the helpers separately.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
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: Will Deacon <will.deacon@arm.com>
Cc: alexei.starovoitov@gmail.com
Cc: ard.biesheuvel@linaro.org
Cc: oss-drivers@netronome.com
Cc: yamada.masahiro@socionext.com
Link: https://lkml.kernel.org/r/20190330000854.30142-2-jakub.kicinski@netronome.comSigned-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/jump_label_ratelimit.h

@@ -12,21 +12,79 @@ struct static_key_deferred {
 	struct delayed_work work;
 };
 
-extern void static_key_slow_dec_deferred(struct static_key_deferred *key);
-extern void static_key_deferred_flush(struct static_key_deferred *key);
+struct static_key_true_deferred {
+	struct static_key_true key;
+	unsigned long timeout;
+	struct delayed_work work;
+};
+
+struct static_key_false_deferred {
+	struct static_key_false key;
+	unsigned long timeout;
+	struct delayed_work work;
+};
+
+#define static_key_slow_dec_deferred(x)					\
+	__static_key_slow_dec_deferred(&(x)->key, &(x)->work, (x)->timeout)
+#define static_branch_slow_dec_deferred(x)				\
+	__static_key_slow_dec_deferred(&(x)->key.key, &(x)->work, (x)->timeout)
+
+#define static_key_deferred_flush(x)					\
+	__static_key_deferred_flush((x), &(x)->work)
+
+extern void
+__static_key_slow_dec_deferred(struct static_key *key,
+			       struct delayed_work *work,
+			       unsigned long timeout);
+extern void __static_key_deferred_flush(void *key, struct delayed_work *work);
 extern void
 jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl);
 
+extern void jump_label_update_timeout(struct work_struct *work);
+
+#define DEFINE_STATIC_KEY_DEFERRED_TRUE(name, rl)			\
+	struct static_key_true_deferred name = {			\
+		.key =		{ STATIC_KEY_INIT_TRUE },		\
+		.timeout =	(rl),					\
+		.work =	__DELAYED_WORK_INITIALIZER((name).work,		\
+						   jump_label_update_timeout, \
+						   0),			\
+	}
+
+#define DEFINE_STATIC_KEY_DEFERRED_FALSE(name, rl)			\
+	struct static_key_false_deferred name = {			\
+		.key =		{ STATIC_KEY_INIT_FALSE },		\
+		.timeout =	(rl),					\
+		.work =	__DELAYED_WORK_INITIALIZER((name).work,		\
+						   jump_label_update_timeout, \
+						   0),			\
+	}
+
+#define static_branch_deferred_inc(x)	static_branch_inc(&(x)->key)
+
 #else	/* !CONFIG_JUMP_LABEL */
 struct static_key_deferred {
 	struct static_key  key;
 };
+struct static_key_true_deferred {
+	struct static_key_true key;
+};
+struct static_key_false_deferred {
+	struct static_key_false key;
+};
+#define DEFINE_STATIC_KEY_DEFERRED_TRUE(name, rl)	\
+	struct static_key_true_deferred name = { STATIC_KEY_TRUE_INIT }
+#define DEFINE_STATIC_KEY_DEFERRED_FALSE(name, rl)	\
+	struct static_key_false_deferred name = { STATIC_KEY_FALSE_INIT }
+
+#define static_branch_slow_dec_deferred(x)	static_branch_dec(&(x)->key)
+
 static inline void static_key_slow_dec_deferred(struct static_key_deferred *key)
 {
 	STATIC_KEY_CHECK_USE(key);
 	static_key_slow_dec(&key->key);
 }
-static inline void static_key_deferred_flush(struct static_key_deferred *key)
+static inline void static_key_deferred_flush(void *key)
 {
 	STATIC_KEY_CHECK_USE(key);
 }

kernel/jump_label.c

@@ -244,12 +244,13 @@ static void __static_key_slow_dec(struct static_key *key,
 	cpus_read_unlock();
 }
 
-static void jump_label_update_timeout(struct work_struct *work)
+void jump_label_update_timeout(struct work_struct *work)
 {
 	struct static_key_deferred *key =
 		container_of(work, struct static_key_deferred, work.work);
 	__static_key_slow_dec(&key->key, 0, NULL);
 }
+EXPORT_SYMBOL_GPL(jump_label_update_timeout);
 
 void static_key_slow_dec(struct static_key *key)
 {
@@ -264,19 +265,21 @@ void static_key_slow_dec_cpuslocked(struct static_key *key)
 	__static_key_slow_dec_cpuslocked(key, 0, NULL);
 }
 
-void static_key_slow_dec_deferred(struct static_key_deferred *key)
+void __static_key_slow_dec_deferred(struct static_key *key,
+				    struct delayed_work *work,
+				    unsigned long timeout)
 {
 	STATIC_KEY_CHECK_USE(key);
-	__static_key_slow_dec(&key->key, key->timeout, &key->work);
+	__static_key_slow_dec(key, timeout, work);
 }
-EXPORT_SYMBOL_GPL(static_key_slow_dec_deferred);
+EXPORT_SYMBOL_GPL(__static_key_slow_dec_deferred);
 
-void static_key_deferred_flush(struct static_key_deferred *key)
+void __static_key_deferred_flush(void *key, struct delayed_work *work)
 {
 	STATIC_KEY_CHECK_USE(key);
-	flush_delayed_work(&key->work);
+	flush_delayed_work(work);
 }
-EXPORT_SYMBOL_GPL(static_key_deferred_flush);
+EXPORT_SYMBOL_GPL(__static_key_deferred_flush);
 
 void jump_label_rate_limit(struct static_key_deferred *key,
 		unsigned long rl)