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De Francesco" To: Greg Kroah-Hartman Cc: Larry Finger , Phillip Potter , Pavel Skripkin , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/3] staging: r8188eu: Shorten calls chain of rtw_read8/16/32() Date: Thu, 09 Sep 2021 09:53:02 +0200 Message-ID: <7885982.jm2Fxi49sr@localhost.localdomain> In-Reply-To: References: <20210904220048.12822-1-fmdefrancesco@gmail.com> <20210904220048.12822-3-fmdefrancesco@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > > Co-developed-by: Pavel Skripkin > > Signed-off-by: Pavel Skripkin > > Signed-off-by: Fabio M. De Francesco > > --- > > > > 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 >