Am Dienstag, den 25.08.2015, 11:58 +0200 schrieb Krzysztof Opasiak:
>
> On 08/24/2015 11:09 PM, Stefan Koch wrote:
> > The kernel supports the device authorization because of wireless USB.
> > These is usable for wired USB devices, too.
> > These new interface authorization allows to enable or disable
> > individual interfaces instead a whole device.
> >
> > If a deauthorized interface will be authorized so the driver probing must
> > be triggered manually by writing INTERFACE to /sys/bus/usb/drivers_probe
> >
> > Signed-off-by: Stefan Koch <stefan.koch10@xxxxxxxxx>
> > ---
> > drivers/usb/core/message.c | 38 ++++++++++++++++++++++++++++++++++++++
> > drivers/usb/core/usb.h | 2 ++
> > 2 files changed, 40 insertions(+)
> >
> > diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
> > index 3d25d89..c090f50 100644
> > --- a/drivers/usb/core/message.c
> > +++ b/drivers/usb/core/message.c
> > @@ -1555,6 +1555,44 @@ static void usb_release_interface(struct device *dev)
> > kfree(intf);
> > }
> >
> > +/*
> > + * usb_deauthorize_interface - deauthorize an USB interface
> > + *
> > + * @intf: USB interface structure
> > + */
> > +void usb_deauthorize_interface(struct usb_interface *intf)
> > +{
> > + struct device *dev = &intf->dev;
> > +
> > + device_lock(dev->parent);
> > +
> > + if (intf->authorized) {
> > + device_lock(dev);
> > + intf->authorized = 0;
> > + device_unlock(dev);
> > +
> > + usb_forced_unbind_intf(intf);
> > + }
> > +
> > + device_unlock(dev->parent);
> > +}
> > +
> > +/*
> > + * usb_authorize_interface - authorize an USB interface
> > + *
> > + * @intf: USB interface structure
> > + */
> > +void usb_authorize_interface(struct usb_interface *intf)
> > +{
> > + struct device *dev = &intf->dev;
> > +
> > + if (!intf->authorized) {
> > + device_lock(dev);
> > + intf->authorized = 1; /* authorize interface */
> > + device_unlock(dev);
> > + }
> > +}
> > +
>
> Why usb_deauthorize_interface() takes both dev->parent and dev locks and
> usb_authorize_interface() takes only dev lock?
>
Because usb_forced_unbind_intf() needs the devices lock...
In the auth case, we change only a flag.
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