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    SubjectRe: [PATCH v6 16/19] staging: r8188eu: Clean up rtw_read*() and rtw_write*()
    On Thu, Sep 16, 2021 at 02:14:14PM +0200, Fabio M. De Francesco wrote:
    > 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?
    >

    In the original code the last two bytes of "data" were uninitialized.
    KASan will spot this as a bug, but it doesn't affect runtime because we
    mask away those bytes anyway.

    > > > }
    > > >
    > > > 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?
    >

    Yeah. The original code was buggy but it still worked fine. Ideally
    this kind of logic fix would be in a separate patch from the other
    "rename a variable" changes.

    regards,
    dan carpenter

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