Commit 593efa40 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

USB: allow some usb functions to take a const pointer. 

The functions to_usb_interface(), to_usb_device, and
interface_to_usbdev() sometimes would like to take a const * and return
a const * back.  As we are doing pointer math, a call to container_of()
loses the const-ness of a pointer, so use a _Generic() macro to pick the
proper inline function to call instead.

Link: https://lore.kernel.org/r/20221016104155.1260201-1-gregkh@linuxfoundation.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7ebe49b7

include/linux/usb.h

+52 −3
Original line number Diff line number Diff line
@@ -258,7 +258,27 @@ struct usb_interface { 
	struct device *usb_dev;

	struct work_struct reset_ws;	/* for resets in atomic context */

};

#define	to_usb_interface(d) container_of(d, struct usb_interface, dev)



static inline struct usb_interface *__to_usb_interface(struct device *d)

{

	return container_of(d, struct usb_interface, dev);

}



static inline const struct usb_interface *__to_usb_interface_const(const struct device *d)

{

	return container_of(d, struct usb_interface, dev);

}



/*

 * container_of() will happily take a const * and spit back a non-const * as it

 * is just doing pointer math.  But we want to be a bit more careful in the USB

 * driver code, so manually force any const * of a device to also be a const *

 * to a usb_device.

 */

#define to_usb_interface(dev)						\

	_Generic((dev),							\

		 const struct device *: __to_usb_interface_const,	\

		 struct device *: __to_usb_interface)(dev)



static inline void *usb_get_intfdata(struct usb_interface *intf)

{
@@ -709,12 +729,41 @@ struct usb_device { 
	u16 hub_delay;

	unsigned use_generic_driver:1;

};

#define	to_usb_device(d) container_of(d, struct usb_device, dev)



static inline struct usb_device *interface_to_usbdev(struct usb_interface *intf)

static inline struct usb_device *__to_usb_device(struct device *d)

{

	return container_of(d, struct usb_device, dev);

}



static inline const struct usb_device *__to_usb_device_const(const struct device *d)

{

	return container_of(d, struct usb_device, dev);

}



/*

 * container_of() will happily take a const * and spit back a non-const * as it

 * is just doing pointer math.  But we want to be a bit more careful in the USB

 * driver code, so manually force any const * of a device to also be a const *

 * to a usb_device.

 */

#define to_usb_device(dev)					\

	_Generic((dev),						\

		 const struct device *: __to_usb_device_const,	\

		 struct device *: __to_usb_device)(dev)



static inline struct usb_device *__intf_to_usbdev(struct usb_interface *intf)

{

	return to_usb_device(intf->dev.parent);

}

static inline const struct usb_device *__intf_to_usbdev_const(const struct usb_interface *intf)

{

	return to_usb_device((const struct device *)intf->dev.parent);

}



#define interface_to_usbdev(intf)					\

	_Generic((intf),						\

		 const struct usb_interface *: __intf_to_usbdev_const,	\

		 struct usb_interface *: __intf_to_usbdev)(intf)



extern struct usb_device *usb_get_dev(struct usb_device *dev);

extern void usb_put_dev(struct usb_device *dev);