On Thu, Sep 09, 2021 at 07:17:57AM +0000, Linyu Yuan (QUIC) wrote:
>
>
> > From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Sent: Thursday, September 9, 2021 2:11 PM
> > To: Linyu Yuan (QUIC) <quic_linyyuan@xxxxxxxxxxx>
> > Cc: Felipe Balbi <balbi@xxxxxxxxxx>; linux-usb@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH] usb: dwc3: gadget: clear gadget pointer after exit
> >
> > On Thu, Sep 09, 2021 at 01:45:47PM +0800, Linyu Yuan wrote:
> > > change device release function to clear gadget pointer.
> >
> > That does not properly describe what and why this change is needed.
> >
> > >
> > > Signed-off-by: Linyu Yuan <quic_linyyuan@xxxxxxxxxxx>
> > > ---
> > > drivers/usb/dwc3/gadget.c | 5 +++--
> > > 1 file changed, 3 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > > index 804b505..e2ab5f6 100644
> > > --- a/drivers/usb/dwc3/gadget.c
> > > +++ b/drivers/usb/dwc3/gadget.c
> > > @@ -4188,9 +4188,10 @@ static int dwc3_gadget_get_irq(struct dwc3
> > *dwc)
> > >
> > > static void dwc_gadget_release(struct device *dev)
> > > {
> > > - struct usb_gadget *gadget = container_of(dev, struct usb_gadget,
> > dev);
> > > + struct dwc3 *dwc = dev_get_platdata(dev);
> >
> > Are you sure this is the same?
> Yes, in dwc3_gadget_init()
> usb_initialize_gadget(dwc->dev, dwc->gadget, dwc_gadget_release);
> dev = &dwc->gadget->dev;
> dev->platform_data = dwc;
>
> here original code use follow container_of, it use same dev,
> container_of(dev, struct usb_gadget, dev);
> >
> > >
> > > - kfree(gadget);
> > > + kfree(dwc->gadget);
> > > + dwc->gadget = NULL;
> >
> > Why set this to NULL? Who cares about this now? What changed to make
> > it required?
> It better to set to NULL for better understanding.
Understanding of what? What issue does this fix? You need a reason to
make this, or any, kernel change.
thanks,
greg k-h
