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a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789715801; b=YZzrn/AVjIyE1xMxIDQpwsLfmylp9MbsQwQwwTU+EiBZVpxYhVRjSRuQH+IJ0/CTA/10qb Q56cyZX3+W5iV3EfSVUT1MYNAbLE42/0qXuf4Zvd5Hbw6W88LpVGN6VVyBIP5gwFHeRAHV zRR9Ao7yMgmYZQofMRHytaXLHKlazPQ= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=none; spf=pass (imf24.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=pass (policy=none) header.from=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 619B168C4E; Fri, 18 Sep 2026 09:16:34 +0200 (CEST) Date: Fri, 18 Sep 2026 09:16:34 +0200 From: Christoph Hellwig To: Yu Kuai Cc: Jens Axboe , Josef Bacik , Tejun Heo , Johannes Weiner , Michal =?iso-8859-1?Q?Koutn=FD?= , Jonathan Corbet , Shuah Khan , Randy Dunlap , Coly Li , Kent Overstreet , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , Benjamin Marzinski , Song Liu , Li Nan , Xiao Ni , Andreas Gruenbacher , Matthew Wilcox , Jan Kara , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , Yu Kuai , Christoph Hellwig , Nilay Shroff , Tao Cui , linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@lists.linux.dev, linux-raid@vger.kernel.org, gfs2@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, llvm@lists.linux.dev 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260918041744.1526924-3-yukuai@kernel.org> User-Agent: Mutt/1.5.17 (2007-11-01) X-Stat-Signature: gi913515h75kdup16yygsdxr5tp9ccft X-Rspam-User: X-Rspamd-Queue-Id: 12C56180007 X-Rspamd-Server: rspam03 X-HE-Tag: 1789715800-325303 X-HE-Meta: U2FsdGVkX1/TcuMLbxx0R72yR52BYNiRCjQrSAWnXnWCSuIWOSRY34ZSd71nqhQrxo4ufc/1/7Uq0j6qA77n08QYUXoBoQRkfi43DfrpRiqNCvSU0KMmDvc3dOdJMtgoD4gqPelcrB/CMWvfQ8/DjbCfxQo1i68Cgx2Z/BxrW2Ddu6GQkCzumPCVOwBgUyNFaPZfliAKNJE9Dz+X0UysSKKDZ+SEHMpmFqVf+RO0XQ8t+RLxIPuRaSAkTgmPjEQiUamvZuhKdW/KhxPilWfJLGN/NhSvE5U2t/TNwoII6mPiRgcycHGdM6O/OQhGsvPdF47tREtyb9uJU3g4t7dE7DyzeYAr8EafyG5i/XaaDzKkVv2d519d9gxK3FvW4vEu9fgqgFcfp38ohiI9BRE1sKfldVEDaXeoTHSp1tNb2rpbWXEsLyD1+dVRPOpOFM7YdJRkB+JmOzd3Q+c4na0mK0IFWWSQhYOEYsaGamaekGfk3Z4w9X3bJ9fzqirIoy/Hex5zVAe2vFNd5S8s3Y2m+8PBhgeHAJt3C1Fv7DrubTK+Uwd6RAAlDJ3MOlV6djuLrb+GevouvORjHou6dNv9GrCq7VwJoyx2Bl/kzDarvwaRIfvMjQ80RCJgtMf7uJZ6Ft+jySo2qo4EvLa7qrIwize/VxJUIjnFFVj5UndlkdzRQXeLL8/irdFbrl7vUHRdR/UrnVqAiBwecWS4JX3oUufFKzsx4pZd4DDFfFa2x5Kz44RBAMn1xZ9OGFykhd2DlVwQtPBD1lp1NxLD18IaTSTfLC8V0nditVPl7l2w5AwMAkIIo3/tuvWfEDa18VM/A/zMf+PWKNoR7AmYot2GvRpFZknPMDS8BkprPse/KEDefAwjtWj386j49CfOZf9rvG5fN1zaQeJ5aW8qRRZzrnNu2G3PGo+eJhqosKFEgwWJ0HTtSAYd1JmdhmB1dp3LKhsOnEF+bvFzLA+uY7a PePK5u+R cYOhZdPqfhaDw+9oOIoKX6wn0TY5dc68b3Dq47529K29q6A7SE0xRvbPa2Ca9IRGCxAU22HU5quL+Cu1CAFEGbHPI7BmGkZk1nFfc Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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.