Re: [PATCH v4 17/18] staging: r8188eu: Shorten calls chain of rtw_read8/16/32()

Fabio M. De Francesco
2021-09-14T12:55:55Z

On Tuesday, September 14, 2021 11:32:58 AM CEST Dan Carpenter wrote:
> On Mon, Sep 13, 2021 at 08:10:01PM +0200, Fabio M. De Francesco wrote:
> > diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/
staging/r8188eu/hal/usb_ops_linux.c
> > index 04402bab805e..75475b0083db 100644
> > --- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
> > +++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
> > @@ -89,6 +89,56 @@ static int usbctrl_vendorreq(struct intf_hdl *intfhdl,
u16 value, void *data, u1
> > return status;
> > }
> >
> > +static int usb_read(struct intf_hdl *intfhdl, u16 addr, void *data, u8
size)
> > +{
> > + int status;
> > + u8 *io_buf; /* pointer to I/O buffer */
> > + struct adapter *adapt = intfhdl->padapter;
> > + struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
> > + struct usb_device *udev = dvobjpriv->pusbdev;
> > +
> > + if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx)
{
> > + status = -EPERM;
> > + goto exit;
> > + }
>
> Just return directly.
>
> if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx)
> return -EPERM;

Dear Dan,

I agree with you, I'll return it directly in v5.

> > +
> > + mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
> > +
> > + io_buf = dvobjpriv->usb_vendor_req_buf;
> > +
> > + status = usb_control_msg_recv(udev, 0, REALTEK_USB_VENQT_CMD_REQ,
> > + REALTEK_USB_VENQT_READ,
addr,
> > + REALTEK_USB_VENQT_CMD_IDX,
io_buf,
> > + size,
RTW_USB_CONTROL_MSG_TIMEOUT,
> > + GFP_KERNEL);
> > + if (!status) {
> > + /* Success this control transfer. */
>
> It's always better to do error handling instead of success handling.

Yes, you're right again. I blindly followed the style that was in the parts
of the code of usbctrl_vendorreq() that I'm reusing here.

> if (status) {
>
> Remove the comment because now it's in the standard format.

OK, those comments are not necessary: I'll remove them.

> > + rtw_reset_continual_urb_error(dvobjpriv);
> > + memcpy(data, io_buf, size);
> > + goto mutex_unlock;
> > + }
> > + /* error cases */
> > + if (status == (-ESHUTDOWN || -ENODEV || -ENOENT)) {
>
> if (status == -ESHUTDOWN ||
> status == -ENODEV ||
> status == -ENOENT) {

This is a stupid mistake and Pavel soon noticed it. Yesterday I sent a
message to ask reviewers for disregarding v4 and wait for v5 with the fix of
this test. :(

However, I noticed that usb_control_msg_recv() might return in "status" some
recoverable errors (like -ENOMEM and others); so I guess that the code must
retry in a while loop (exactly as it did with usb_control_msg() in
usbctrl_vendorreq()).

Actually I'm not 100% sure that the "while" loop is needed. What I know is
that I've been using this version (with _no_ loop) for about a week, not less
than 12 hours a day and I didn't notice any problem...

Can you please tell if a loop for retries is *really* necessary?

>
> > + /*
> > + * device or controller has been disabled due to
> > + * some problem that could not be worked around,
> > + * device or bus doesn’t exist, endpoint does not
> > + * exist or is not enabled.
> > + */
> > + adapt->bSurpriseRemoved = true;
> > + goto mutex_unlock;
>
> Indented wrong.

Yes, it must be fixed.

Regards,

Fabio

>
> > + }
> > + GET_HAL_DATA(adapt)->srestpriv.wifi_error_status =
USB_VEN_REQ_CMD_FAIL;
> > + if (rtw_inc_and_chk_continual_urb_error(dvobjpriv)) {
> > + adapt->bSurpriseRemoved = true;
> > + goto mutex_unlock;
> > + }
> > +mutex_unlock:
> > + mutex_unlock(&dvobjpriv->usb_vendor_req_mutex);
> > +exit:
> > + return status;
> > +}
>
> regards,
> dan carpenter
>