Commit 3b3449c1 authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

block: store the holder kobject in bd_holder_disk 



We hold a reference to the holder kobject for each bd_holder_disk,
so to make the code a bit more robust, use a reference to it instead
of the block_device.  As long as no one clears ->bd_holder_dir in
before freeing the disk, this isn't strictly required, but it does
make the code more clear and more robust.

Orignally-From: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221115141054.1051801-10-yukuai1@huaweicloud.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 62f535e1

block/holder.c

+6 −5
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


struct bd_holder_disk {

	struct list_head	list;

	struct block_device	*bdev;

	struct kobject		*holder_dir;

	int			refcnt;

};
@@ -14,7 +14,7 @@ static struct bd_holder_disk *bd_find_holder_disk(struct block_device *bdev, 
	struct bd_holder_disk *holder;



	list_for_each_entry(holder, &disk->slave_bdevs, list)

		if (holder->bdev == bdev)

		if (holder->holder_dir == bdev->bd_holder_dir)

			return holder;

	return NULL;

}
@@ -94,8 +94,9 @@ int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk) 
	}



	INIT_LIST_HEAD(&holder->list);

	holder->bdev = bdev;

	holder->refcnt = 1;

	holder->holder_dir = bdev->bd_holder_dir;



	ret = add_symlink(disk->slave_dir, bdev_kobj(bdev));

	if (ret)

		goto out_free_holder;
@@ -140,8 +141,8 @@ void bd_unlink_disk_holder(struct block_device *bdev, struct gendisk *disk) 
	holder = bd_find_holder_disk(bdev, disk);

	if (!WARN_ON_ONCE(holder == NULL) && !--holder->refcnt) {

		del_symlink(disk->slave_dir, bdev_kobj(bdev));

		del_symlink(bdev->bd_holder_dir, &disk_to_dev(disk)->kobj);

		kobject_put(bdev->bd_holder_dir);

		del_symlink(holder->holder_dir, &disk_to_dev(disk)->kobj);

		kobject_put(holder->holder_dir);

		list_del_init(&holder->list);

		kfree(holder);

	}