Re: [PATCH v3 9/9] usb: rework usb_maxpacket() using usb_pipe_endpoint()

[Vincent MAILHOL <mailhol.vincent@wanadoo.fr>]

On Thu. 17 Mar 2022 at 02:17, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Thu, Mar 17, 2022 at 01:19:35AM +0900, Vincent Mailhol wrote:
> > Rework the body of usb_maxpacket() in order not to reinvent the wheel
> > and just rely on the usb_pipe_endpoint() helper function instead.
> >
> > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> > ---
> >  include/linux/usb.h | 14 +-------------
> >  1 file changed, 1 insertion(+), 13 deletions(-)
> >
> > diff --git a/include/linux/usb.h b/include/linux/usb.h
> > index 8127782aa7a1..653d34ff0999 100644
> > --- a/include/linux/usb.h
> > +++ b/include/linux/usb.h
> > @@ -1971,19 +1971,7 @@ usb_pipe_endpoint(struct usb_device *dev, unsigned int pipe)
> >
> >  static inline u16 usb_maxpacket(struct usb_device *udev, int pipe)
> >  {
> > -     struct usb_host_endpoint        *ep;
> > -     unsigned                        epnum = usb_pipeendpoint(pipe);
> > -
> > -     if (usb_pipeout(pipe))
> > -             ep = udev->ep_out[epnum];
> > -     else
> > -             ep = udev->ep_in[epnum];
> > -
> > -     if (!ep)
> > -             return 0;
> > -
> > -     /* NOTE:  only 0x07ff bits are for packet size... */
> > -     return usb_endpoint_maxp(&ep->desc);
> > +     return usb_endpoint_maxp(&usb_pipe_endpoint(udev, pipe)->desc);
>
> The original code was careful to handle the case where ep was a NULL
> pointer.  What will your routine do if usb_pipe_endpoint(udev, pipe)
> returns NULL?

Sorry, you are absolutely right. Will send a v4.

Thank you!


Yours sincerely,
Vincent Maihol