Re: [RFC PATCH v2 07/22] ASoC: Add SOC USB APIs for adding an USB backend

[Zhou Furong]

On 2023/1/29 15:09, Greg KH wrote:
> On Sun, Jan 29, 2023 at 02:54:43PM +0800, Zhou Furong wrote:
> > > > +void *snd_soc_usb_get_priv_data(struct device *usbdev)
> > > > +{
> > > > +	struct snd_soc_usb *ctx;
> > > > +
> > > > +	if (!usbdev)
> > > > +		return NULL;
> > >
> > > How could usbdev ever be NULL?
> > The method is exported to public, valid check should be reasonable
> > as someone may call it by mistake
>
> We do not protect the kernel from itself like this, no need to check
> things that should never happen.  If the caller gets it wrong, their
> code will break :)
>
> thanks,
>
> greg k-h

Thank you Greg!

This has been confused me for long time when I found Linux kernel don't 
check input even for public method.