klist: implement KLIST_INIT() and DEFINE_KLIST()

klist is missing static initializers and definition helper.  Add them.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/klist.h

@@ -25,6 +25,14 @@ struct klist {
 	void			(*put)(struct klist_node *);
 };
 
+#define KLIST_INIT(_name, _get, _put)					\
+	{ .k_lock	= __SPIN_LOCK_UNLOCKED(_name.k_lock),		\
+	  .k_list	= LIST_HEAD_INIT(_name.k_list),			\
+	  .get		= _get,						\
+	  .put		= _put, }
+
+#define DEFINE_KLIST(_name, _get, _put)					\
+	struct klist _name = KLIST_INIT(_name, _get, _put)
 
 extern void klist_init(struct klist * k, void (*get)(struct klist_node *),
 		       void (*put)(struct klist_node *));