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Subject: Re: [PATCH 02/14] block: switch register_disk to use
 blkdev_get_by_dev
To:     Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>
Cc:     Josef Bacik <josef@toxicpanda.com>,
        Minchan Kim <minchan@kernel.org>,
        Stefan Haberland <sth@linux.ibm.com>,
        Jan Hoeppner <hoeppner@linux.ibm.com>,
        Joseph Qi <joseph.qi@linux.alibaba.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Pavel Machek <pavel@ucw.cz>, Len Brown <len.brown@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, nbd@other.debian.org,
        linux-ide@vger.kernel.org, linux-s390@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com,
        linux-pm@vger.kernel.org, linux-mm@kvack.org,
        linux-block@vger.kernel.org
References: <20200917165720.3285256-1-hch@lst.de>
 <20200917165720.3285256-3-hch@lst.de>
From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Organization: Brain-dead Software
Message-ID: <091931b1-eb9c-e45e-c9e8-501554618508@gmail.com>
Date:   Fri, 18 Sep 2020 11:52:39 +0300
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Hello!

On 17.09.2020 19:57, Christoph Hellwig wrote:

> Use blkdev_get_by_dev instead of open coding it using bdget_disk +
> blkdev_get.

    I don't see where you are removing bdget_disk() call (situated just before
the below code?)...

> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/genhd.c | 7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/block/genhd.c b/block/genhd.c
> index 7b56203c90a303..f778716fac6cde 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -732,10 +732,9 @@ static void register_disk(struct device *parent, struct gendisk *disk,
>   		goto exit;
>   
>   	set_bit(GD_NEED_PART_SCAN, &disk->state);
> -	err = blkdev_get(bdev, FMODE_READ, NULL);
> -	if (err < 0)
> -		goto exit;
> -	blkdev_put(bdev, FMODE_READ);
> +	bdev = blkdev_get_by_dev(disk_devt(disk), FMODE_READ, NULL);
> +	if (!IS_ERR(bdev))
> +		blkdev_put(bdev, FMODE_READ);
>   
>   exit:
>   	/* announce disk after possible partitions are created */

MBR, Sergei