dm review needed, was: Re: [PATCH v3 2/3] blk-cgroup: store blkcg in bio instead of blkg

[Christoph Hellwig]

On Fri, Sep 18, 2026 at 12:17:43PM +0800, Yu Kuai wrote:
>  static inline void dm_bio_record(struct dm_bio_details *bd, struct bio *bio)
>  {
>  	bd->bi_bdev = bio->bi_bdev;
> -	bd->bi_flags = bio->bi_flags;
> +	/*
> +	 * Restoring BIO_BLKG_REF would not recreate its associated reference.
> +	 */
> +	bd->bi_flags = bio->bi_flags & ~(1U << BIO_BLKG_REF);

But do we need to restore the reference?  I have to admit that
this surrounding code is very confusing and I would really like
to have the dm maintainers look over it.