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SubjectRe: [patch 2/2] [media] ds3000: off by one in ds3000_read_snr()


Am 17.01.2012 08:30, schrieb Dan Carpenter:
> This is a static checker patch and I don't have the hardware to test
> this, so please review it carefully. The dvbs2_snr_tab[] array has 80
> elements so when we cap it at 80, that's off by one. I would have
> assumed that the test was wrong but in the lines right before we have
> the same test but use "snr_reading - 1" as the array offset. I've done
> the same thing here.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> diff --git a/drivers/media/dvb/frontends/ds3000.c b/drivers/media/dvb/frontends/ds3000.c
> index af65d01..3f5ae0a 100644
> --- a/drivers/media/dvb/frontends/ds3000.c
> +++ b/drivers/media/dvb/frontends/ds3000.c
> @@ -681,7 +681,7 @@ static int ds3000_read_snr(struct dvb_frontend *fe, u16 *snr)
> snr_reading = dvbs2_noise_reading / tmp;
> if (snr_reading > 80)
> snr_reading = 80;
> - *snr = -(dvbs2_snr_tab[snr_reading] / 1000);
> + *snr = -(dvbs2_snr_tab[snr_reading - 1] / 1000);
> }
> dprintk("%s: raw / cooked = 0x%02x / 0x%04x\n", __func__,
> snr_reading, *snr);

hi dan,

perhaps it is more useful to do it in the check above ?
thinking about that why not replace the number (80) with ARRAY_SIZE() ?

re,
wh





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