jump_label: Provide jump_label_key initializers

Provide two initializers for jump_label_key that initialize it enabled
or disabled. Also modify all jump_label code to allow for jump_labels to be
initialized enabled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jason Baron <jbaron@redhat.com>
Link: http://lkml.kernel.org/n/tip-p40e3yj21b68y03z1yv825e7@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/jump_label.h

@@ -128,4 +128,7 @@ static inline void jump_label_rate_limit(struct jump_label_key_deferred *key,
 }
 #endif	/* HAVE_JUMP_LABEL */
 
+#define jump_label_key_enabled	((struct jump_label_key){ .enabled = ATOMIC_INIT(1), })
+#define jump_label_key_disabled	((struct jump_label_key){ .enabled = ATOMIC_INIT(0), })
+
 #endif	/* _LINUX_JUMP_LABEL_H */

kernel/jump_label.c

@@ -248,8 +248,13 @@ void jump_label_apply_nops(struct module *mod)
 	if (iter_start == iter_stop)
 		return;
 
-	for (iter = iter_start; iter < iter_stop; iter++)
-		arch_jump_label_transform_static(iter, JUMP_LABEL_DISABLE);
+	for (iter = iter_start; iter < iter_stop; iter++) {
+		struct jump_label_key *iterk;
+
+		iterk = (struct jump_label_key *)(unsigned long)iter->key;
+		arch_jump_label_transform_static(iter, jump_label_enabled(iterk) ?
+				JUMP_LABEL_ENABLE : JUMP_LABEL_DISABLE);
+	}
 }
 
 static int jump_label_add_module(struct module *mod)
@@ -289,8 +294,7 @@ static int jump_label_add_module(struct module *mod)
 		key->next = jlm;
 
 		if (jump_label_enabled(key))
-			__jump_label_update(key, iter, iter_stop,
-					    JUMP_LABEL_ENABLE);
+			__jump_label_update(key, iter, iter_stop, JUMP_LABEL_ENABLE);
 	}
 
 	return 0;