Hi, Alan Stern <[email protected]> writes: > On Mon, 3 Apr 2017, Roger Quadros wrote: > >> allow usb_del_gadget_udc() and usb add_gadget_udc() to be called >> repeatedly on the same gadget->dev structure. >> >> We need to clear the gadget->dev structure so that kobject_init() >> doesn't complain about already initialized object. >> >> Signed-off-by: Roger Quadros <[email protected]> >> --- >> drivers/usb/gadget/udc/core.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c >> index d685d82..efce68e 100644 >> --- a/drivers/usb/gadget/udc/core.c >> +++ b/drivers/usb/gadget/udc/core.c >> @@ -1273,6 +1273,7 @@ void usb_del_gadget_udc(struct usb_gadget *gadget) >> flush_work(&gadget->work); >> device_unregister(&udc->dev); >> device_unregister(&gadget->dev); >> + memset(&gadget->dev, 0x00, sizeof(gadget->dev)); >> } >> EXPORT_SYMBOL_GPL(usb_del_gadget_udc); > > Isn't this dangerous? It's quite possible that the device_unregister()
not on the gadget API, no.
> call on the previous line invokes the gadget->dev.release callback,
> which might deallocate gadget. If that happens, your new memset will
> oops.
that won't happen. struct usb_gadget is a member of the UDC's private
structure, like this:
struct dwc3 {
[...]
struct usb_gadget gadget;
struct usb_gadget_driver *gadget_driver;
[...]
};
I'm actually thinking that struct usb_gadget shouldn't have a struct
device at all. Just a pointer to a device, that would solve all these
issues.
--
balbi
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