Use kobj_to_dev() instead of container_of()
Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>