locking/atomic, kref: Add KREF_INIT()

Since we need to change the implementation, stop exposing internals.

Provide KREF_INIT() to allow static initialization of struct kref.

Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Paul E. McKenney <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

drivers/block/drbd/drbd_bitmap.c

···
 		.done = 0,
 		.flags = flags,
 		.error = 0,
-		.kref = { ATOMIC_INIT(2) },
+		.kref = KREF_INIT(2),
 	};
 
 	if (!get_ldev_if_state(device, D_ATTACHING)) {  /* put is in drbd_bm_aio_ctx_destroy() */

fs/fuse/fuse_i.h

···
 
 #define FUSE_IO_PRIV_SYNC(f) \
 {					\
-	.refcnt = { ATOMIC_INIT(1) },	\
+	.refcnt = KREF_INIT(1),		\
 	.async = 0,			\
 	.file = f,			\
 }

include/linux/kref.h

···
 	atomic_t refcount;
 };
 
+#define KREF_INIT(n)	{ .refcount = ATOMIC_INIT(n), }
+
 /**
  * kref_init - initialize object.
  * @kref: object in question.

init/version.c

···
 #endif
 
 struct uts_namespace init_uts_ns = {
-	.kref = {
-		.refcount	= ATOMIC_INIT(2),
-	},
+	.kref = KREF_INIT(2),
 	.name = {
 		.sysname	= UTS_SYSNAME,
 		.nodename	= UTS_NODENAME,

kernel/pid.c

···
  * the scheme scales to up to 4 million PIDs, runtime.
  */
 struct pid_namespace init_pid_ns = {
-	.kref = {
-		.refcount       = ATOMIC_INIT(2),
-	},
+	.kref = KREF_INIT(2),
 	.pidmap = {
 		[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
 	},