Re: [PATCH V2 for-4.21 1/2] blk-mq: not embed .mq_kobj and ctx->kobj into queue instance

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

On Fri, Nov 16, 2018 at 07:23:10PM +0800, Ming Lei wrote:
> @@ -456,7 +456,7 @@ struct request_queue {
>  	/*
>  	 * mq queue kobject
>  	 */
> -	struct kobject mq_kobj;
> +	struct kobject *mq_kobj;

What is this kobject even used for?  It wasn't obvious at all from this
patch, why is it needed if you are not using it to reference count the
larger structure here?

thanks,

greg k-h