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From:   Feng Li <lifeng1519@gmail.com>
Date:   Tue, 12 Jan 2021 23:34:06 +0800
Message-ID: <CAEK8JBD68oTcuV+Cf-S1Vv-n6nyr5UM_zWA5iJFHP=UvQ14AZg@mail.gmail.com>
Subject: Re: [PATCH] blk: avoid divide-by-zero with zero granularity
To:     Li Feng <fengli@smartx.com>
Cc:     Jens Axboe <axboe@kernel.dk>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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I'm sorry, ignore this one.

Li Feng <fengli@smartx.com> =E4=BA=8E2021=E5=B9=B41=E6=9C=8812=E6=97=A5=E5=
=91=A8=E4=BA=8C =E4=B8=8B=E5=8D=8811:30=E5=86=99=E9=81=93=EF=BC=9A
>
> If the physical_block_size and io_min is less than a sector, the
> 'granularity >> SECTOR_SHIFT' will be zero.
>
> Signed-off-by: Li Feng <fengli@smartx.com>
> ---
>  include/linux/blkdev.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index f94ee3089e01..4d029e95adb4 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1485,6 +1485,10 @@ static inline int queue_alignment_offset(const str=
uct request_queue *q)
>  static inline int queue_limit_alignment_offset(struct queue_limits *lim,=
 sector_t sector)
>  {
>         unsigned int granularity =3D max(lim->physical_block_size, lim->i=
o_min);
> +       granularity =3D granularity >> SECTOR_SHIFT;
> +       if (!granularity)
> +               return 0;
> +
>         unsigned int alignment =3D sector_div(sector, granularity >> SECT=
OR_SHIFT)
>                 << SECTOR_SHIFT;
>
> --
> 2.29.2
>