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, 2 insertions, 7 deletions

diff --git a/block/cmd-filter.c b/block/cmd-filter.c
index 79c14996ac11..e669aed4c6bc 100644
--- a/block/cmd-filter.c
+++ b/block/cmd-filter.c
@@ -211,14 +211,10 @@ int blk_register_filter(struct gendisk *disk)
 {
         int ret;
         struct blk_cmd_filter *filter = &disk->queue->cmd_filter;
-        struct kobject *parent = kobject_get(disk->holder_dir->parent);
 
-        if (!parent)
-                return -ENODEV;
-
-        ret = kobject_init_and_add(&filter->kobj, &rcf_ktype, parent,
+        ret = kobject_init_and_add(&filter->kobj, &rcf_ktype,
+                                   &disk_to_dev(disk)->kobj,
                                    "%s", "cmd_filter");
-
         if (ret < 0)
                 return ret;
 
@@ -231,7 +227,6 @@ void blk_unregister_filter(struct gendisk *disk)
         struct blk_cmd_filter *filter = &disk->queue->cmd_filter;
 
         kobject_put(&filter->kobj);
-        kobject_put(disk->holder_dir->parent);
 }
 EXPORT_SYMBOL(blk_unregister_filter);
 #endif