linux-kernel - Re: [PATCH v6 16/19] staging: r8188eu: Clean up rtw_read*() and rtw

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Message-ID: <20210916113606.GJ2116@kadam>
Date:   Thu, 16 Sep 2021 14:36:06 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>
Cc:     Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Pavel Skripkin <paskripkin@...il.com>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org,
        David Laight <david.Laight@...lab.com>
Subject: Re: [PATCH v6 16/19] staging: r8188eu: Clean up rtw_read*() and
 rtw_write*()

On Wed, Sep 15, 2021 at 11:11:00PM +0200, Fabio M. De Francesco wrote:
> Clean up rtw_read{8,16,32}() and rtw_write{8,16,32,N}() in usb_ops_linux.c.
> 

It would be good to know what you did more specifically.

1) Rename variables:
	pio_priv => io_priv
	pintfhdl => intfhdl
	wvalue => address.
2) Remove unnecessary casts.
3) Fix types.  Use __le16 instead of __le32.

The last one is a small KASan bug fix.  So good job on that.

> Co-developed-by: Pavel Skripkin <paskripkin@...il.com>
> Signed-off-by: Pavel Skripkin <paskripkin@...il.com>
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@...il.com>
> ---
>  drivers/staging/r8188eu/hal/usb_ops_linux.c | 68 ++++++++++-----------
>  1 file changed, 34 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/staging/r8188eu/hal/usb_ops_linux.c
> index 2098ce935dc0..d87da84eca07 100644
> --- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
> +++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
> @@ -91,91 +91,91 @@ static int usbctrl_vendorreq(struct intf_hdl *intfhdl, u16 value, void *data, u1
>  
>  u8 rtw_read8(struct adapter *adapter, u32 addr)
>  {
> -	struct io_priv *pio_priv = &adapter->iopriv;
> -	struct intf_hdl *pintfhdl = &pio_priv->intf;
> -	u16 wvalue = (u16)(addr & 0x0000ffff);
> +	struct io_priv *io_priv = &adapter->iopriv;
> +	struct intf_hdl *intfhdl = &io_priv->intf;
> +	u16 address = addr & 0xffff;
>  	u8 data;
> -

Deleting this line introduces a checkpatch warning.

> -	usbctrl_vendorreq(pintfhdl, wvalue, &data, 1, REALTEK_USB_VENQT_READ);
> +	usbctrl_vendorreq(intfhdl, address, &data, 1, REALTEK_USB_VENQT_READ);
>  
>  	return data;
>  }
>  
>  u16 rtw_read16(struct adapter *adapter, u32 addr)
>  {
> -	struct io_priv *pio_priv = &adapter->iopriv;
> -	struct intf_hdl *pintfhdl = &pio_priv->intf;
> -	u16 wvalue = (u16)(addr & 0x0000ffff);
> -	__le32 data;
> +	struct io_priv *io_priv = &adapter->iopriv;
> +	struct intf_hdl *intfhdl = &io_priv->intf;
> +	u16 address = addr & 0xffff;
> +	__le16 data;
>  
> -	usbctrl_vendorreq(pintfhdl, wvalue, &data, 2, REALTEK_USB_VENQT_READ);
> +	usbctrl_vendorreq(intfhdl, address, &data, 2, REALTEK_USB_VENQT_READ);
>  
> -	return (u16)(le32_to_cpu(data) & 0xffff);
> +	return le16_to_cpu(data);

The last two bytes of "data" are not initialized.  I do not think that
will cause a bug on either endian type of system during runtime but I
this that KASan will catch it and complain.

>  }
>  
>  u32 rtw_read32(struct adapter *adapter, u32 addr)
>  {
> -	struct io_priv *pio_priv = &adapter->iopriv;
> -	struct intf_hdl *pintfhdl = &pio_priv->intf;
> -	u16 wvalue = (u16)(addr & 0x0000ffff);
> +	struct io_priv *io_priv = &adapter->iopriv;
> +	struct intf_hdl *intfhdl = &io_priv->intf;
> +	u16 address = addr & 0xffff;
>  	__le32 data;
>  
> -	usbctrl_vendorreq(pintfhdl, wvalue, &data, 4, REALTEK_USB_VENQT_READ);
> +	usbctrl_vendorreq(intfhdl, address, &data, 4, REALTEK_USB_VENQT_READ);
>  
>  	return le32_to_cpu(data);
>  }
>  
>  int rtw_write8(struct adapter *adapter, u32 addr, u8 val)
>  {
> -	struct io_priv *pio_priv = &adapter->iopriv;
> -	struct intf_hdl *pintfhdl = &pio_priv->intf;
> -	u16 wvalue = (u16)(addr & 0x0000ffff);
> +	struct io_priv *io_priv = &adapter->iopriv;
> +	struct intf_hdl *intfhdl = &io_priv->intf;
> +	u16 address = addr & 0xffff;
>  	int ret;
>  
> -	ret = usbctrl_vendorreq(pintfhdl, wvalue, &val, 1, REALTEK_USB_VENQT_WRITE);
> +	ret = usbctrl_vendorreq(intfhdl, address, &val, 1, REALTEK_USB_VENQT_WRITE);
>  
>  	return RTW_STATUS_CODE(ret);
>  }
>  
>  int rtw_write16(struct adapter *adapter, u32 addr, u16 val)
>  {
> -	struct io_priv *pio_priv = &adapter->iopriv;
> -	struct intf_hdl *pintfhdl = &pio_priv->intf;
> -	u16 wvalue = (u16)(addr & 0x0000ffff);
> -	__le32 data = cpu_to_le32(val & 0x0000ffff);
> +	struct io_priv *io_priv = &adapter->iopriv;
> +	struct intf_hdl *intfhdl = &io_priv->intf;
> +	__le16 data = cpu_to_le16(val);

This is the other interesting change.  I think the original code works
though.

> +	u16 address = addr & 0xffff;
>  	int ret;
>  
> -	ret = usbctrl_vendorreq(pintfhdl, wvalue, &data, 2, REALTEK_USB_VENQT_WRITE);
> +	ret = usbctrl_vendorreq(intfhdl, address, &data, 2, REALTEK_USB_VENQT_WRITE);
>  
>  	return RTW_STATUS_CODE(ret);
>  }

regards,
dan carpenter