Re: [PATCH v6 16/19] staging: r8188eu: Clean up rtw_read*() and rtw_write*()

["Fabio M. De Francesco" <fmdefrancesco@gmail.com>]

On Thursday, September 16, 2021 1:36:06 PM CEST Dan Carpenter wrote:
> 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.

Dear Dan,

I'm sorry for missing that. :( 

Now I remember that you asked for this specifications at least once (if not 
twice). I'll redo the commit message and add the list above in v7. I guess 
that I have to do the same in 15/19.

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

Thanks (even if I don't yet know anything about KASan).

> > Co-developed-by: Pavel Skripkin <paskripkin@gmail.com>
> > Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.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.

I didn't notice the warning. This too will be fixed in v7.

> > -	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.

I don't want to add mistakes on mistakes. I guess that you are talking of the 
same fix you wrote above and that "return le16_to_cpu(data);" is correct.
Am I interpreting your words in the correct way?
 
> >  }
> >  
> >  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.

Here too, I'm a bit confused... Do yo prefer the original code or you're 
saying that, although the original code works fine, I made the correct choice 
in changing it? Can you please confirm?

> 
> > +	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
> 
> 

Regards,

Fabio