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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Sun, 31 Oct 2021 10:47:22 -0700
Message-ID: <CAPcyv4gU0q=UhDhGoDjK1mwS8WNcWYUXgEb7Rd8Amqr1XFs6ow@mail.gmail.com>
Subject: Re: [PATCH 03/13] nvdimm/btt: do not call del_gendisk() if not needed
To:     Luis Chamberlain <mcgrof@kernel.org>
Cc:     Jens Axboe <axboe@kernel.dk>, Geoff Levand <geoff@infradead.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, Jim Paris <jim@jtan.com>,
        Minchan Kim <minchan@kernel.org>,
        Nitin Gupta <ngupta@vflare.org>, senozhatsky@chromium.org,
        Richard Weinberger <richard@nod.at>, miquel.raynal@bootlin.com,
        vigneshr@ti.com, Vishal L Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        "Weiny, Ira" <ira.weiny@intel.com>,
        Keith Busch <kbusch@kernel.org>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>, linux-block@vger.kernel.org,
        linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
        linux-mtd@lists.infradead.org,
        Linux NVDIMM <nvdimm@lists.linux.dev>,
        linux-nvme@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Oct 15, 2021 at 4:53 PM Luis Chamberlain <mcgrof@kernel.org> wrote:
>
> We know we don't need del_gendisk() if we haven't added
> the disk, so just skip it. This should fix a bug on older
> kernels, as del_gendisk() became able to deal with
> disks not added only recently, after the patch titled
> "block: add flag for add_disk() completion notation".

Perhaps put this in:

    commit $abbrev_commit ("block: add flag for add_disk() completion notation")

...format, but I can't seem to find that commit?

If you're touching the changelog how about one that clarifies the
impact and drops "we"?

"del_gendisk() is not required if the disk has not been added. On
kernels prior to commit $abbrev_commit ("block: add flag for
add_disk() completion notation")
it is mandatory to not call del_gendisk() if the underlying device has
not been through device_add()."

Fixes: 41cd8b70c37a ("libnvdimm, btt: add support for blk integrity")

With that you can add:

Reviewed-by: Dan Williams <dan.j.williams@intel.com>