block: move holder_dir from disk to part0

Move disk->holder_dir to part0->holder_dir.  Kill now mostly
superflous bdev_get_holder().

While at it, kill superflous kobject_get/put() around holder_dir,
slave_dir and cmd_filter creation and collapse
disk_sysfs_add_subdirs() into register_disk().  These serve no purpose
but obfuscating the code.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 4411bdd671dd..2c0e1b597ab4 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -141,7 +141,6 @@ struct gendisk {
 
         int flags;
         struct device *driverfs_dev;  // FIXME: remove
-        struct kobject *holder_dir;
         struct kobject *slave_dir;
 
         struct timer_rand_state *random;