Re: [PATCH] media: dvb_ringbuffer : Fix a bug in dvb_ringbuffer.c

[유용수]

Dear All,

Can you pay your attention to this patch ?
This is a very simple modification.
But, too much time has already passed since I sent the first E-mail.

2022년 8월 3일 (수) 오후 9:04, 유용수 <yongsuyoo0215@xxxxxxxxx>님이 작성:
>
> Dear All.
> Too much time has already passed since I first sent this Email.
> Can you share how this patch is going ?
>
> 2022년 6월 23일 (목) 오후 6:11, 유용수 <yongsuyoo0215@xxxxxxxxx>님이 작성:
> >
> > Dear Kieran Bingham
> >
> > I sent E-mail again by Linux terminal by using the command " ... git
> > send-email .."
> > I believe that you will surely get the diff file.
> >
> > Thank you
> >
> > 2022년 6월 22일 (수) 오후 10:12, Hans Petter Selasky <hps@xxxxxxxxxxx>님이 작성:
> > >
> > > Hi Kieran,
> > >
> > > The consumed variable should not be negative. This bug has been there
> > > since the beginning of the GIT at Linux from what I can see.
> > >
> > > +1
> > >
> > > --HPS
> > >
> > >  From 108c6acb2cc4bc4314b96f6f254a04b2873a096c Mon Sep 17 00:00:00 2001
> > > From: YongSu Yoo <yongsuyoo0215@xxxxxxxxx>
> > > Date: Sun, 22 May 2022 04:53:12 +0000
> > > Subject: [PATCH] media: dvb_ringbuffer : Fix a bug in dvb_ringbuffer.c
> > >
> > > Signed-off-by:Yongsu Yoo <yongsuyoo0215@xxxxxxxxx>
> > >
> > > The function dvb_ringbuffer_pkt_next in
> > > /linux-next/drviers/media/dvb-core/dvb_ringbuffer.c,
> > > which searches the idx of the next valid packet in the ring
> > > buffer of the ca->slot_info[slot].rx_buffer at
> > > /linux-next/drivers/media/dvb-core/dvb_ca_en50221.c,
> > > has the following problem.
> > > In calculating the amounts of the consumed address of the ring
> > > buffer, if the read address(rbuf->pread) of the ring buffer is
> > > smaller than the idx, the amounts of the searched address
> > > should be (idx - rbuf->pread),
> > > whereas if the read address(rbuf->pread) of the ring buffer is
> > > larger than the idx, the amounts of the consumed address should
> > > be (idx - rbuf->pread + rbug->size). But there exists an
> > > incorrect logic that the rbug-size was not properly added on
> > > (idx - rbug->pread) in the later case. With this commit, we
> > > fixed this bug.
> > > ---
> > >   drivers/media/dvb-core/dvb_ringbuffer.c | 4 +++-
> > >   1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/media/dvb-core/dvb_ringbuffer.c
> > > b/drivers/media/dvb-core/dvb_ringbuffer.c
> > > index d1d471af0636..7d4558de8e83 100644
> > > --- a/drivers/media/dvb-core/dvb_ringbuffer.c
> > > +++ b/drivers/media/dvb-core/dvb_ringbuffer.c
> > > @@ -335,7 +335,9 @@ ssize_t dvb_ringbuffer_pkt_next(struct
> > > dvb_ringbuffer *rbuf, size_t idx, size_t*
> > >                 idx = (idx + curpktlen + DVB_RINGBUFFER_PKTHDRSIZE) % rbuf->size;
> > >         }
> > >
> > > -       consumed = (idx - rbuf->pread) % rbuf->size;
> > > +       consumed = (idx - rbuf->pread);
> > > +       if (consumed < 0)
> > > +               consumed += rbuf->size;
> > >
> > >         while((dvb_ringbuffer_avail(rbuf) - consumed) >
> > > DVB_RINGBUFFER_PKTHDRSIZE) {
> > >
> > > --
> > > 2.17.1