RE: [PATCH 2/2] gadget: Support for the usb charger framework

[Peter Chen]

> >>  /**
> >>   * struct usb_udc - describes one usb device controller @@ -127,12
> >> +128,45 @@ void usb_gadget_giveback_request(struct usb_ep *ep,  }
> >> EXPORT_SYMBOL_GPL(usb_gadget_giveback_request);
> >>
> >> +int usb_gadget_register_notify(struct usb_gadget *gadget,
> >> +                            struct notifier_block *nb) {
> >> +     unsigned long flags;
> >> +     int ret;
> >> +
> >> +     spin_lock_irqsave(&gadget->lock, flags);
> >
> > I find you use so many spin_lock_irqsave, any reasons for that?
> > Why mutex_lock can't be used?
> >
> 
> The spin_lock_irqsave() can make it as a atomic notifier, that can make sure the
> gadget state event can be quickly reported to the user who register a notifier
> on the gadget device. Is it OK?
> 

I don't think it is a good reason, spin_lock_irqsave is usually used for protecting
data which is accessed at atomic environment. 

Peter