Re: [PATCH v2 04/11] USB: core: hub.c: use usb_control_msg_send() in a few places

[Greg Kroah-Hartman]

On Mon, Sep 07, 2020 at 11:08:58AM -0400, Alan Stern wrote:
> On Mon, Sep 07, 2020 at 04:51:01PM +0200, Greg Kroah-Hartman wrote:
> > There are a few calls to usb_control_msg() that can be converted to use
> > usb_control_msg_send() instead, so do that in order to make the error
> > checking a bit simpler and the code smaller.
> > 
> > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> > v2:
> >  - dropped changes to usb_req_set_sel() thanks to review from Alan
> 
> > @@ -4056,7 +4035,7 @@ static void usb_enable_link_state(struct usb_hcd *hcd, struct usb_device *udev,
> >  	 * associated with the link state we're about to enable.
> >  	 */
> >  	ret = usb_req_set_sel(udev, state);
> > -	if (ret < 0) {
> > +	if (ret) {
> >  		dev_warn(&udev->dev, "Set SEL for device-initiated %s failed.\n",
> >  				usb3_lpm_names[state]);
> >  		return;
> 
> Did this change survive by mistake?
> 
> Actually, it looks like usb_req_set_sel needs to check the value 
> returned by usb_control_msg -- a perfect example of the sort of thing 
> you were trying to fix in the first place!

Ugh, good catch, and yes, the original code is buggy :)

thanks,

greg k-h