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Date:   Wed, 30 Mar 2022 09:18:12 -0700
From:   "Darrick J. Wong" <djwong@kernel.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Shiyang Ruan <ruansy.fnst@fujitsu.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-xfs <linux-xfs@vger.kernel.org>,
        Linux NVDIMM <nvdimm@lists.linux.dev>,
        Linux MM <linux-mm@kvack.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        david <david@fromorbit.com>, Jane Chu <jane.chu@oracle.com>
Subject: Re: [PATCH v11 1/8] dax: Introduce holder for dax_device
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On Wed, Mar 30, 2022 at 08:49:29AM -0700, Christoph Hellwig wrote:
> On Wed, Mar 30, 2022 at 06:58:21PM +0800, Shiyang Ruan wrote:
> > As the code I pasted before, pmem driver will subtract its ->data_offset,
> > which is byte-based. And the filesystem who implements ->notify_failure()
> > will calculate the offset in unit of byte again.
> > 
> > So, leave its function signature byte-based, to avoid repeated conversions.
> 
> I'm actually fine either way, so I'll wait for Dan to comment.

FWIW I'd convinced myself that the reason for using byte units is to
make it possible to reduce the pmem failure blast radius to subpage
units... but then I've also been distracted for months. :/

--D