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Subject: Re: [PATCH] media: pvrusb2: fix parsing error
To:     Tong Zhang <ztong0001@gmail.com>, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, mchehab@kernel.org, isely@pobox.com
References: <20200816064901.977682-1-ztong0001@gmail.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <75b8354b-362a-0215-8038-45bd68be7de5@xs4all.nl>
Date:   Wed, 19 Aug 2020 16:38:00 +0200
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Hi Tong,

On 16/08/2020 08:49, Tong Zhang wrote:
> pvr2_std_str_to_id() returns 0 on failure and 1 on success,
> however the caller is checking failure case using <0
> 
> Signed-off-by: Tong Zhang <ztong0001@gmail.com>
> ---
>  drivers/media/usb/pvrusb2/pvrusb2-hdw.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/pvrusb2/pvrusb2-hdw.c b/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
> index 1cfb7cf64131..db5aa66c1936 100644
> --- a/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
> +++ b/drivers/media/usb/pvrusb2/pvrusb2-hdw.c
> @@ -867,7 +867,8 @@ static int ctrl_std_sym_to_val(struct pvr2_ctrl *cptr,
>  	int ret;
>  	v4l2_std_id id;
>  	ret = pvr2_std_str_to_id(&id,bufPtr,bufSize);
> -	if (ret < 0) return ret;
> +	if (ret == 0)
> +		return ret;

But now you return 0 instead of an error when pvr2_std_str_to_id failed.

Just do this:

	if (!pvr2_std_str_to_id(&id,bufPtr,bufSize))
		return -EINVAL;

And you can drop the ret variable as well since that's no longer needed.

Regards,

	Hans

>  	if (mskp) *mskp = id;
>  	if (valp) *valp = id;
>  	return 0;
>