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>

4 files changed, 6 insertions, 29 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
diff --git a/fs/block_dev.c b/fs/block_dev.c
index c982a9107979..57d572642854 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -548,14 +548,6 @@ static struct kobject *bdev_get_kobj(struct block_device *bdev)
                 return kobject_get(&disk_to_dev(bdev->bd_disk)->kobj);
 }
 
-static struct kobject *bdev_get_holder(struct block_device *bdev)
-{
-        if (bdev->bd_contains != bdev)
-                return kobject_get(bdev->bd_part->holder_dir);
-        else
-                return kobject_get(bdev->bd_disk->holder_dir);
-}
-
 static int add_symlink(struct kobject *from, struct kobject *to)
 {
         if (!from || !to)
@@ -608,7 +600,7 @@ static int bd_holder_grab_dirs(struct block_device *bdev,
         if (!bo->sdev)
                 goto fail_put_hdev;
 
-        bo->hdir = bdev_get_holder(bdev);
+        bo->hdir = kobject_get(bdev->bd_part->holder_dir);
         if (!bo->hdir)
                 goto fail_put_sdev;
 
diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index ace6d03602c7..f0f604950ff4 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -305,16 +305,6 @@ struct device_type part_type = {
         .release        = part_release,
 };
 
-static inline void disk_sysfs_add_subdirs(struct gendisk *disk)
-{
-        struct kobject *k;
-
-        k = kobject_get(&disk_to_dev(disk)->kobj);
-        disk->holder_dir = kobject_create_and_add("holders", k);
-        disk->slave_dir = kobject_create_and_add("slaves", k);
-        kobject_put(k);
-}
-
 static void delete_partition_rcu_cb(struct rcu_head *head)
 {
         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
@@ -464,7 +454,8 @@ void register_disk(struct gendisk *disk)
                 return;
         }
 #endif
-        disk_sysfs_add_subdirs(disk);
+        disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
+        disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 
         /* No minors to use for partitions */
         if (!disk_partitionable(disk))
@@ -592,7 +583,7 @@ void del_gendisk(struct gendisk *disk)
         disk_stat_set_all(disk, 0);
         disk->stamp = 0;
 
-        kobject_put(disk->holder_dir);
+        kobject_put(disk->part0.holder_dir);
         kobject_put(disk->slave_dir);
         disk->driverfs_dev = NULL;
 #ifndef CONFIG_SYSFS_DEPRECATED
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;