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Subject: Re: [PATCH] media: ccs: replace snprintf in show functions with sysfs_emit
From:   Kieran Bingham <kieran.bingham@ideasonboard.com>
Cc:     Qing Wang <wangqing@vivo.com>
To:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        Qing Wang <wangqing@vivo.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-media@vger.kernel.org
Date:   Fri, 15 Oct 2021 23:36:33 +0100
Message-ID: <163433739388.456562.9392744334237641054@Monstersaurus>
User-Agent: alot/0.9.1
Precedence: bulk

Hello,

Quoting Qing Wang (2021-10-15 07:49:22)
> show() must not use snprintf() when formatting the value to be
> returned to user space.
>=20
> Fix the following coccicheck warning:
> drivers/media/i2c/ccs/ccs-core.c:2717: WARNING: use scnprintf or sprintf.
>=20
> Use sysfs_emit instead of scnprintf or sprintf makes more sense.
>=20
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
>  drivers/media/i2c/ccs/ccs-core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/media/i2c/ccs/ccs-core.c b/drivers/media/i2c/ccs/ccs=
-core.c
> index a9403a2..21a156d 100644
> --- a/drivers/media/i2c/ccs/ccs-core.c
> +++ b/drivers/media/i2c/ccs/ccs-core.c
> @@ -2715,11 +2715,11 @@ ccs_sysfs_ident_read(struct device *dev, struct d=
evice_attribute *attr,

What version of the kernel is this patch against?

I can't find the direct line mapping for this in either the linux-media
tree or torvalds master branch (closest match at
https://git.linuxtv.org/media_tree.git/tree/drivers/media/i2c/ccs/ccs-core.=
c#n2754)

Ah: https://lore.kernel.org/all/20210603071750.11594-1-thunder.leizhen@huaw=
ei.com/
updated this, so I suspect this patch has been submitted against perhaps
a v5.14 kernel? It would be best to rebase and repost against the latest
branch of https://git.linuxtv.org/media_tree.git


>         struct ccs_module_info *minfo =3D &sensor->minfo;
> =20
>         if (minfo->mipi_manufacturer_id)
> -               return snprintf(buf, PAGE_SIZE, "%4.4x%4.4x%2.2x\n",
> +               return sysfs_emit(buf, "%4.4x%4.4x%2.2x\n",
>                                 minfo->mipi_manufacturer_id, minfo->model=
_id,
>                                 minfo->revision_number) + 1;

This change looks good, but I think it might be better to re-indent the
minfo lines to match as well...

>         else
> -               return snprintf(buf, PAGE_SIZE, "%2.2x%4.4x%2.2x\n",
> +               return sysfs_emit(buf, "%2.2x%4.4x%2.2x\n",
>                                 minfo->smia_manufacturer_id, minfo->model=
_id,
>                                 minfo->revision_number) + 1;

here as well of course.

--
Kieran


>  }
> --=20
> 2.7.4
>