linux-kernel - Re: [PATCH] media: dvb_demux: Fix a bug for the continuity counter

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Message-ID: <CANXPkT4QS1OO_BW5xWguNxa3jXVjwfFTxPmHYAYT=+MRc-FZOg@mail.gmail.com>
Date:   Sun, 16 Apr 2023 21:02:09 +0900
From:   YongSu Yoo <yongsuyoo0215@...il.com>
To:     0215yys@...mail.net, yongsu.yoo@....com, mchehab@...nel.org,
        tommaso.merciai@...rulasolutions.com, yongsuyoo0215@...il.com,
        hverkuil-cisco@...all.nl, colin.i.king@...il.com,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: dvb_demux: Fix a bug for the continuity counter

Hi ~ Everyone
Can you share how this patch is going ?

2023년 3월 6일 (월) 오전 6:25, <yongsuyoo0215@...il.com>님이 작성:
>
> From: YongSu Yoo <yongsuyoo0215@...il.com>
>
> Signed-off-by: Yongsu Yoo <yongsuyoo0215@...il.com>
>
> In dvb_demux.c, some logics exist which compare the expected
> continuity counter and the real continuity counter. If they
> are not matched each other, both of the expected continuity
> counter and the real continuity counter should be printed.
> But there exists a bug that the expected continuity counter
> is not correctly printed. The expected continuity counter is
> replaced with the real countinuity counter + 1 so that
> the epected continuity counter is not correclty printed.
> This is wrong. This bug is fixed.
> ---
>  drivers/media/dvb-core/dvb_demux.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/dvb-core/dvb_demux.c b/drivers/media/dvb-core/dvb_demux.c
> index 398c86279b5b..7c4d86bfdd6c 100644
> --- a/drivers/media/dvb-core/dvb_demux.c
> +++ b/drivers/media/dvb-core/dvb_demux.c
> @@ -115,12 +115,12 @@ static inline int dvb_dmx_swfilter_payload(struct dvb_demux_feed *feed,
>
>         cc = buf[3] & 0x0f;
>         ccok = ((feed->cc + 1) & 0x0f) == cc;
> -       feed->cc = cc;
>         if (!ccok) {
>                 set_buf_flags(feed, DMX_BUFFER_FLAG_DISCONTINUITY_DETECTED);
>                 dprintk_sect_loss("missed packet: %d instead of %d!\n",
>                                   cc, (feed->cc + 1) & 0x0f);
>         }
> +       feed->cc = cc;
>
>         if (buf[1] & 0x40)      // PUSI ?
>                 feed->peslen = 0xfffa;
> @@ -300,7 +300,6 @@ static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
>
>         cc = buf[3] & 0x0f;
>         ccok = ((feed->cc + 1) & 0x0f) == cc;
> -       feed->cc = cc;
>
>         if (buf[3] & 0x20) {
>                 /* adaption field present, check for discontinuity_indicator */
> @@ -336,6 +335,7 @@ static int dvb_dmx_swfilter_section_packet(struct dvb_demux_feed *feed,
>                 feed->pusi_seen = false;
>                 dvb_dmx_swfilter_section_new(feed);
>         }
> +       feed->cc = cc;
>
>         if (buf[1] & 0x40) {
>                 /* PUSI=1 (is set), section boundary is here */
> --
> 2.17.1
>