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Date: Tue, 7 Apr 2026 22:46:26 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Christoph =?iso-8859-1?Q?B=F6hmwalder?= <christoph.boehmwalder@linbit.com>
Subject: Re: [PATCH 08/20] drbd: add DAX/PMEM support for metadata access
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References: <20260327223820.2244227-1-christoph.boehmwalder@linbit.com>
	<20260327223820.2244227-9-christoph.boehmwalder@linbit.com>
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Cc: Jens Axboe <axboe@kernel.dk>, nvdimm@lists.linux.dev,
	Dave Jiang <dave.jiang@intel.com>, Vishal Verma <vishal.l.verma@intel.com>,
	Philipp Reisner <philipp.reisner@linbit.com>,
	linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
	Lars Ellenberg <lars.ellenberg@linbit.com>,
	an Williams <dan.j.williams@intel.com>, drbd-dev@lists.linbit.com
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Adding the dax maintainers and they really need to review this.

> +	long want = (drbd_md_last_sector(bdev) + 1 - first_sector) >> (PAGE_SHIFT - SECTOR_SHIFT);
> +	pgoff_t pgoff = first_sector >> (PAGE_SHIFT - SECTOR_SHIFT);
> +	long md_offset_byte = (bdev->md.md_offset - first_sector) << SECTOR_SHIFT;
> +	long al_offset_byte = (al_sector - first_sector) << SECTOR_SHIFT;

You really want helpers to make all these unit conversions maintainable.