linux-kernel - Re: [PATCH v2] iio: adc: qcom-pm8xxx-xoadc: Remove useless condition in pm8xxx_xoadc_parse

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Message-ID: <20230318154853.0c91e055@jic23-huawei>
Date:   Sat, 18 Mar 2023 15:48:53 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     Kasumov Ruslan <xhxgldhlpfy@...il.com>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Andi Shyti <andi.shyti@...nel.org>,
        linux-arm-msm@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-kernel@...r.kernel.org, lvc-project@...uxtesting.org,
        Kasumov Ruslan <s02210418@....cs.msu.ru>
Subject: Re: [PATCH v2] iio: adc: qcom-pm8xxx-xoadc: Remove useless
 condition in pm8xxx_xoadc_parse_channel()

On Wed, 15 Mar 2023 16:51:14 +0300
Kasumov Ruslan <xhxgldhlpfy@...il.com> wrote:

> The left side of the loop condition never becomes false.
> hwchan cannot be NULL, because it points to elements of the
> hw_channels array that takes one of 4 predefined values:
> pm8018_xoadc_channels, pm8038_xoadc_channels,
> pm8058_xoadc_channels, pm8921_xoadc_channels.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Reviewed-by: Andi Shyti <andi.shyti@...nel.org>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
> Signed-off-by: Kasumov Ruslan <s02210418@....cs.msu.ru>

We could file this under the category of (overly) paranoid checking that
he variant structure has the hw_channels set, but given there are only 4 instances
of that it is (as you have done) easy to check.

So fair enough to drop this check.

Applied.

Thanks,

Jonathan

> ---
> v2: Removed "Fixes" tag as Andi Shyti <andi.shyti@...nel.org> suggested.
>  drivers/iio/adc/qcom-pm8xxx-xoadc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> index eb424496ee1d..64a3aeb6261c 100644
> --- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> +++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
> @@ -758,7 +758,7 @@ static int pm8xxx_xoadc_parse_channel(struct device *dev,
>  	/* Find the right channel setting */
>  	chid = 0;
>  	hwchan = &hw_channels[0];
> -	while (hwchan && hwchan->datasheet_name) {
> +	while (hwchan->datasheet_name) {
>  		if (hwchan->pre_scale_mux == pre_scale_mux &&
>  		    hwchan->amux_channel == amux_channel)
>  			break;