Re: [PATCH] cxacru: ignore cx82310_eth devices

[Greg KH <greg@kroah.com>]

On Sun, Sep 05, 2010 at 07:01:11PM +0200, Ondrej Zary wrote:
> On Sunday 05 September 2010 06:03:52 Greg KH wrote:
> > On Sat, Sep 04, 2010 at 05:30:20PM +0100, Simon Arlott wrote:
> > > Ignore ADSL routers, which can have the same vendor and product IDs
> > > as ADSL modems but should be handled by the cx82310_eth driver.
> > >
> > > This intentionally ignores device IDs that aren't currently handled
> > > by cx82310_eth. There may be other device IDs that perhaps shouldn't
> > > be claimed by cxacru.
> > >
> > > Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> > > [SA: Moved to cxacru_usb_probe, message level lowered to info]
> > > Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
> > > ---
> > >  drivers/usb/atm/cxacru.c |   18 ++++++++++++++++--
> > >  1 files changed, 16 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/usb/atm/cxacru.c b/drivers/usb/atm/cxacru.c
> > > index 593fc5e..96fa736 100644
> > > --- a/drivers/usb/atm/cxacru.c
> > > +++ b/drivers/usb/atm/cxacru.c
> > > @@ -1324,8 +1324,22 @@ static struct usbatm_driver cxacru_driver = {
> > >  	.tx_padding	= 11,
> > >  };
> > >
> > > -static int cxacru_usb_probe(struct usb_interface *intf, const struct
> > > usb_device_id *id) -{
> > > +static int cxacru_usb_probe(struct usb_interface *intf,
> > > +		const struct usb_device_id *id) {
> > > +	struct usb_device *usb_dev = interface_to_usbdev(intf);
> > > +	char buf[15];
> > > +
> > > +	/* avoid ADSL routers (cx82310_eth)
> > > +	 * abort if bDeviceClass is 0xff and iProduct is "USB NET CARD" */
> > > +	if (usb_dev->descriptor.bDeviceClass == 0xff
> >
> > vendor class?  We have a macro for that?
> >
> > > +			&& usb_dev->descriptor.iProduct
> >
> > Almost everyone has a iProduct, right?  Why even test for that?
> >
> > > +			&& usb_string(usb_dev,
> > > +				usb_dev->descriptor.iProduct, buf, sizeof(buf))
> >
> > usb_string() should handle a 0 string, right?
> >
> > > +			&& !strcmp(buf, "USB NET CARD")) {
> >
> > Just to make it a bit easier to follow, how about you do the
> > usb_string() call in the if statment, and then compare the string and
> >
> > then, if that matches you do:
> > > +		dev_info(&intf->dev, "ignoring cx82310_eth device\n");
> > > +		return -ENODEV;
> 
> Does it look that much better?:
> 
> 	if (usb_dev->descriptor.bDeviceClass == USB_CLASS_VENDOR_SPEC
> 			&& usb_string(usb_dev, usb_dev->descriptor.iProduct,
> 				buf, sizeof(buf)) > 0)
> 		if (!strcmp(buf, "USB NET CARD")) {
> 			dev_info(&intf->dev, "ignoring cx82310_eth device\n");
> 			return -ENODEV;
> 		}

Yes, don't you think so?

> I also found a bug in my first patch - usb_string() can return negative value 
> which can cause problems when not checked for.

Ah, nice catch.  Care to resend it now?

thanks,

greg k-h