Re: [PATCH 1/4] net: usbnet: use usb_control_msg_recv() and usb_control_msg_send()

Himadri Pandya
2020-09-23T14:08:28Z

On Wed, Sep 23, 2020 at 3:54 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Wed, Sep 23, 2020 at 02:35:16PM +0530, Himadri Pandya wrote:
> > Potential incorrect use of usb_control_msg() has resulted in new wrapper
> > functions to enforce its correct usage with proper error check. Hence
> > use these new wrapper functions instead of calling usb_control_msg()
> > directly.
> >
> > Signed-off-by: Himadri Pandya <himadrispandya@gmail.com>
> > ---
> > drivers/net/usb/usbnet.c | 46 ++++------------------------------------
> > 1 file changed, 4 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
> > index 2b2a841cd938..a38a85bef46a 100644
> > --- a/drivers/net/usb/usbnet.c
> > +++ b/drivers/net/usb/usbnet.c
> > @@ -1982,64 +1982,26 @@ EXPORT_SYMBOL(usbnet_link_change);
> > static int __usbnet_read_cmd(struct usbnet *dev, u8 cmd, u8 reqtype,
> > u16 value, u16 index, void *data, u16 size)
> > {
> > - void *buf = NULL;
> > - int err = -ENOMEM;
> > -
> > netdev_dbg(dev->net, "usbnet_read_cmd cmd=0x%02x reqtype=%02x"
> > " value=0x%04x index=0x%04x size=%d\n",
> > cmd, reqtype, value, index, size);
> >
> > - if (size) {
> > - buf = kmalloc(size, GFP_KERNEL);
> > - if (!buf)
> > - goto out;
> > - }
> > -
> > - err = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> > - cmd, reqtype, value, index, buf, size,
> > + return usb_control_msg_recv(dev->udev, 0,
> > + cmd, reqtype, value, index, data, size,
> > USB_CTRL_GET_TIMEOUT);
> > - if (err > 0 && err <= size) {
> > - if (data)
> > - memcpy(data, buf, err);
> > - else
> > - netdev_dbg(dev->net,
> > - "Huh? Data requested but thrown away.\n");
> > - }
> > - kfree(buf);
> > -out:
> > - return err;
> > }
>
> Now there is no real need for these wrapper functions at all, except for
> the debugging which I doubt anyone needs anymore.
>
> So how about just deleting these and calling the real function instead?
>

Yes, that would be a better thing to do.

Thanks,
Himadri

> thanks,
>
> greg k-h