Re: [PATCH v3 4/6] staging: r8188eu: add error handling of rtw_read16

[Pavel Skripkin]

On 8/25/21 7:35 AM, Fabio M. De Francesco wrote:
> On Tuesday, August 24, 2021 9:27:35 AM CEST Pavel Skripkin wrote:
> > _rtw_read16 function can fail in case of usb transfer failure. But
> > previous function prototype wasn't designed to return an error to
> > caller. It can cause a lot uninit value bugs all across the driver code,
> > since rtw_read16() returns local stack variable to caller.
> >
> > Fix it by changing the prototype of this function. Now it returns an
> > int: 0 on success, negative error value on failure and callers should pass
> > the pointer to storage location for register value.
> >
> > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
> >
> > [...]
> >
> > -static u16 usb_read16(struct intf_hdl *pintfhdl, u32 addr)
> > +static int usb_read16(struct intf_hdl *pintfhdl, u32 addr, u16 *data)
> >  {
> >  	u8 requesttype;
> >  	u16 wvalue;
> >  	u16 len;
> > -	__le32 data;
> > +	int res;
> > +	__le32 tmp;
> > +
> > +	if (WARN_ON(unlikely(!data)))
> > +		return -EINVAL;
> >  
> >  	requesttype = 0x01;/* read_in */
> >  	wvalue = (u16)(addr & 0x0000ffff);
> >  	len = 2;
> > -	usbctrl_vendorreq(pintfhdl, wvalue, &data, len, requesttype);
> > +	res = usbctrl_vendorreq(pintfhdl, wvalue, &tmp, len, requesttype);
> > +	if (res < 0) {
> > +		dev_err(dvobj_to_dev(pintfhdl->pintf_dev), "Failed to read 16 bytes: %d\n", res);
> > +		return res;
> > +	} else if (res != len) {
>
> Dear Pavel,
>
> Please note that if and when my patch "Use usb_control_msg_recv / send () in
> usbctrl_vendorreq ()" will be merged, "if (res! = len)" will always evaluate 'true'
> and usb_read16 () will always return -EIO even if usbctrl_vendorreq () succeeds.

Yep, thank you, but it depends on which series will go in first :)

There is a chance, that you will need to clean up this part, if mine 
will be merged before yours



With regards,
Pavel Skripkin