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Date: Fri, 18 Sep 2026 09:16:34 +0200
From: Christoph Hellwig <hch@lst.de>
To: Yu Kuai <yukuai@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>, Josef Bacik <josef@toxicpanda.com>,
	Tejun Heo <tj@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>,
	Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>,
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	Benjamin Marzinski <bmarzins@redhat.com>,
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Subject: dm review needed, was: Re: [PATCH v3 2/3] blk-cgroup: store blkcg
 in bio instead of blkg
Message-ID: <20260918071634.GA10884@lst.de>
References: <20260918041744.1526924-1-yukuai@kernel.org> <20260918041744.1526924-3-yukuai@kernel.org>
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In-Reply-To: <20260918041744.1526924-3-yukuai@kernel.org>
User-Agent: Mutt/1.5.17 (2007-11-01)

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.