On Monday, September 6, 2021 4:07:26 PM CEST Greg Kroah-Hartman wrote:
> On Sun, Sep 05, 2021 at 12:00:47AM +0200, Fabio M. De Francesco wrote:
> > Shorten the calls chain of rtw_read8/16/32() down to the actual reads.
> > For this purpose unify the three usb_read8/16/32 into the new
> > usb_read(); make the latter parameterizable with 'size'; embed most of
> > the code of usbctrl_vendorreq() into usb_read() and use in it the new
> > usb_control_msg_recv() API of USB Core.
> >
> > Suggested-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Co-developed-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
> > Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
> > ---
> >
> > v2->v3: No changes.
> >
> > v1->v2: No changes.
> >
> > drivers/staging/r8188eu/hal/usb_ops_linux.c | 92 +++++++++++++++++----
> > 1 file changed, 78 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/staging/r8188eu/hal/usb_ops_linux.c b/drivers/
staging/r8188eu/hal/usb_ops_linux.c
> > index a87b0d2e87d0..f9c4fd5a2c53 100644
> > --- a/drivers/staging/r8188eu/hal/usb_ops_linux.c
> > +++ b/drivers/staging/r8188eu/hal/usb_ops_linux.c
> > @@ -97,38 +97,102 @@ static int usbctrl_vendorreq(struct intf_hdl
*pintfhdl, u16 value, void *pdata,
> > return status;
> > }
> >
> > +static int usb_read(struct intf_hdl *intfhdl, u32 addr, void *data, u8
size)
> > +{
> > + u16 value = (u16)(addr & 0x0000ffff);
>
> Why not just pass in the address as a 16bit value?
Yes, it should be better. It will be done in v4.
>
>
> > + struct adapter *adapt = intfhdl->padapter;
> > + struct dvobj_priv *dvobjpriv = adapter_to_dvobj(adapt);
> > + struct usb_device *udev = dvobjpriv->pusbdev;
> > + int status;
> > + u8 *io_buf;
> > + int vendorreq_times = 0;
> > +
> > + if (adapt->bSurpriseRemoved || adapt->pwrctrlpriv.pnp_bstop_trx)
{
> > + status = -EPERM;
> > + goto exit;
>
> This is "interesting" to see if it's really even working as they think
> it does, but let's leave it alone for now...
As you suggest, I also prefer to leave it alone for now.
>
> > + }
> > +
> > + mutex_lock(&dvobjpriv->usb_vendor_req_mutex);
> > +
> > + /* Acquire IO memory for vendorreq */
> > + io_buf = dvobjpriv->usb_vendor_req_buf;
> > +
> > + if (!io_buf) {
> > + DBG_88E("[%s] io_buf == NULL\n", __func__);
>
> How can this buffer ever be NULL?
As you noticed a few lines below this, I moved some code around and ignored
and left as was anything that wasn't functional for my purpose..
>
> > + status = -ENOMEM;
> > + goto release_mutex;
> > + }
>
> Why share a buffer at all anyway?
Same answer as above.
>
> > + while (++vendorreq_times <= MAX_USBCTRL_VENDORREQ_TIMES) {
> > + status = usb_control_msg_recv(udev, 0,
REALTEK_USB_VENQT_CMD_REQ,
> > +
REALTEK_USB_VENQT_READ, value,
> > +
REALTEK_USB_VENQT_CMD_IDX, io_buf,
> > + size,
RTW_USB_CONTROL_MSG_TIMEOUT,
> > + GFP_KERNEL);
> > + if (!status) { /* Success this control transfer. */
>
> Comments go on the next line.
This will be fixed in v4, although I'm not sure if this comment and the next
are really necessary. The code seems self-explanatory.
>
> > + rtw_reset_continual_urb_error(dvobjpriv);
> > + memcpy(data, io_buf, size);
> > + } else { /* error cases */
>
> Again, next line for the comment.
Same as above.
>
> > + DBG_88E("reg 0x%x, usb %s %u fail, status:
%d vendorreq_times:%d\n",
> > + value, "read", size, status,
vendorreq_times);
>
> These should be removed eventually...
>
I could use pr_debug() for now or remove it immediately. I'd prefer the
latter but I'm not sure if it is the most appropriate thing to do. Let me
think about it...
> > +
> > + if (status == (-ESHUTDOWN) || status == -
ENODEV) {
> > + adapt->bSurpriseRemoved = true;
>
> Odd, but ok...
>
> > + } else {
> > + struct hal_data_8188e *haldata =
GET_HAL_DATA(adapt);
> > +
> > + haldata-
>srestpriv.wifi_error_status = USB_VEN_REQ_CMD_FAIL;
>
> Why are we not saying the command failed even if the device was removed?
This question is not clear to me. Are you talking about -ENOENT?
I suppose it should be if (status == (-ESHUTDOWN || -ENODEV || -ENOENT)) ...
> But if we do say an error happened, why are we trying to send this out
> again? What would happen to make it work the second time?
There are some errors that are unrecoverable and the loop has no reason to
re-iterate again and again. I'll break this loop on unrecoverable errors.
I see that usb_submit_urb() at the very end of the calls chain may fail for a
lot of different reasons and some of them are a bit obscure to me
(unfortunately, at the moment I have no time to go deeper into the
architecture and the inner workings of the USB subsystem :) )
I hope that I won't overlook any of them - as far as it regards some of all
possible errors I have doubts in telling whether or not they are
unrecoverable and if some can actually happen in this code :(
> > + }
> > +
> > + if
(rtw_inc_and_chk_continual_urb_error(dvobjpriv)) {
> > + adapt->bSurpriseRemoved = true;
>
> So we try to see if the device was removed again?
This must be changed, let me see if I can understand how. At the moment I
don't have the whole picture.
> > + break;
> > + }
> > + }
> > +
> > + /* firmware download is checksummed, don't retry */
> > + if ((value >= FW_8188E_START_ADDRESS && value <=
FW_8188E_END_ADDRESS) || !status)
> > + break;
>
> Nothing like a special case for firmware magic.
This is something that I really cannot understand, so I think I'll leave it
as-is unless I may get some more hints... :)
> Those calls should just use a different write function entirely,
> eventually, to remove this...
>
> Ok, I know you are just moving code around, this is fine, just pointing
> out things that should be fixed up eventually...
Yes, I'm just moving the code around. Anyway I guess that I can fix/change
most of the things you pointed out.
Thanks very much for your review,
Fabio
>
> thanks,
>
> greg k-h
>
