linux-kernel - Re: [PATCH -next] usb: serial: simplify the ark3116_write

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Message-ID: <X9CtGBNfVIZV2eT6@localhost>
Date:   Wed, 9 Dec 2020 11:55:20 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Zheng Yongjun <zhengyongjun3@...wei.com>
Cc:     johan@...nel.org, gregkh@...uxfoundation.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH -next] usb: serial: simplify the ark3116_write_reg()

On Wed, Dec 09, 2020 at 05:29:17PM +0800, Zheng Yongjun wrote:
> Simplify the return expression.
> 
> Signed-off-by: Zheng Yongjun <zhengyongjun3@...wei.com>
> ---
>  drivers/usb/serial/ark3116.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
> index 71a9206ea1e2..0f9fa0e7c50e 100644
> --- a/drivers/usb/serial/ark3116.c
> +++ b/drivers/usb/serial/ark3116.c
> @@ -77,16 +77,11 @@ struct ark3116_private {
>  static int ark3116_write_reg(struct usb_serial *serial,
>  			     unsigned reg, __u8 val)
>  {
> -	int result;
>  	 /* 0xfe 0x40 are magic values taken from original driver */
> -	result = usb_control_msg(serial->dev,
> -				 usb_sndctrlpipe(serial->dev, 0),
> -				 0xfe, 0x40, val, reg,
> -				 NULL, 0, ARK_TIMEOUT);
> -	if (result)
> -		return result;

Since none of the callers bother to check for errors, how about you add
a dev_err() here similar to the one in ark3116_read_reg() instead?

> -
> -	return 0;

Keeping the explicit zero-return on success has the benefit of allowing
the casual developer to know what to expect when using this helper
without having to read the documentation (or implementation) of
usb_control_msg().

> +	return usb_control_msg(serial->dev,
> +			       usb_sndctrlpipe(serial->dev, 0),
> +			       0xfe, 0x40, val, reg,
> +			       NULL, 0, ARK_TIMEOUT);
>  }
>  
>  static int ark3116_read_reg(struct usb_serial *serial,

Johan