linux-kernel - Re: [PATCH v5,8/8] media: mediatek: vcodec: Add dbgfs help function

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAGXv+5FFS6cC+drzXfAbtoEq8b_-9sA1Ry4Xb74hndCkCNiSSA@mail.gmail.com>
Date:   Tue, 30 May 2023 18:15:07 +0800
From:   Chen-Yu Tsai <wenst@...omium.org>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     Yunfei Dong <yunfei.dong@...iatek.com>,
        Nicolas Dufresne <nicolas.dufresne@...labora.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Benjamin Gaignard <benjamin.gaignard@...labora.com>,
        Nícolas F . R . A . Prado 
        <nfraprado@...labora.com>, Nathan Hebert <nhebert@...omium.org>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Fritz Koenig <frkoenig@...omium.org>,
        Daniel Vetter <daniel@...ll.ch>,
        Steve Cho <stevecho@...omium.org>, linux-media@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com
Subject: Re: [PATCH v5,8/8] media: mediatek: vcodec: Add dbgfs help function

On Tue, May 30, 2023 at 6:06 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com> wrote:
>
> Il 25/05/23 04:12, Yunfei Dong ha scritto:
> > Getting dbgfs help information with command "echo -help > vdec".
> >
> > Signed-off-by: Yunfei Dong <yunfei.dong@...iatek.com>
> > ---
> >   .../mediatek/vcodec/mtk_vcodec_dbgfs.c        | 24 ++++++++++++++++++-
> >   1 file changed, 23 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > index 237d0dc8a1fc..2372fc449b45 100644
> > --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c
> > @@ -52,6 +52,23 @@ static void mtk_vdec_dbgfs_get_format_type(struct mtk_vcodec_ctx *ctx, char *buf
> >       *used += curr_len;
> >   }
> >
> > +static void mtk_vdec_dbgfs_get_help(char *buf, int *used, int total)
> > +{
> > +     int curr_len;
> > +
> > +     curr_len = snprintf(buf + *used, total - *used,
> > +                         "help: (1: echo -'info' > vdec 2: cat vdec)\n");
> > +     *used += curr_len;
> > +
> > +     curr_len = snprintf(buf + *used, total - *used,
> > +                         "\t-picinfo: get resolution\n");
> > +     *used += curr_len;
> > +
> > +     curr_len = snprintf(buf + *used, total - *used,
> > +                         "\t-format: get output & capture queue format\n");
> > +     *used += curr_len;
> > +}
> > +
> >   static ssize_t mtk_vdec_dbgfs_write(struct file *filp, const char __user *ubuf,
> >                                   size_t count, loff_t *ppos)
> >   {
> > @@ -84,6 +101,11 @@ static ssize_t mtk_vdec_dbgfs_read(struct file *filp, char __user *ubuf,
> >       if (!buf)
> >               return -ENOMEM;
> >
> > +     if (strstr(dbgfs->dbgfs_buf, "-help")) {
>
> I would print the help strings in two conditions:
> 1. -help
> 2. (nothing)
>
> ...so that if you don't echo anything to vdec (no params), you get the help text.
> Otherwise, you would have to know that "-help" is a parameter that gives you help
> text in the first place.
>
> As for this commit "as is", it works as intended and it is useful to retrieve
> the help text; you can either send a followup commit that extends the help to
> the corner case that I've explained, or send a v6 adding that to this same commit.
>
> I would prefer to see a v6 -- BUT -- since this series was sent a long time ago,
> you will get my R-b and I will leave the final choice to Hans.
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>

The help file could just exist as a separate file. You can then use cleaner
interfaces for it.

ChenYu