USB: mark all struct bus_type as const

Now that the driver core can properly handle constant struct bus_type,
move all of the USB subsystem struct bus_type structures as const,
placing them into read-only memory which can not be modified at runtime.

Cc: Johan Hovold <[e-mail]>
Cc: Evan Green <[e-mail]>
Cc: Alan Stern <[e-mail]>
Cc: [e-mail]
Acked-by: Heikki Krogerus <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/common/ulpi.c

···
 		drv->remove(to_ulpi_dev(dev));
 }
 
-static struct bus_type ulpi_bus = {
+static const struct bus_type ulpi_bus = {
 	.name = "ulpi",
 	.match = ulpi_match,
 	.uevent = ulpi_uevent,

drivers/usb/core/driver.c

···
 
 #endif /* CONFIG_PM */
 
-struct bus_type usb_bus_type = {
+const struct bus_type usb_bus_type = {
 	.name =		"usb",
 	.match =	usb_device_match,
 	.uevent =	usb_uevent,

drivers/usb/core/usb.h

···
 
 #endif
 
-extern struct bus_type usb_bus_type;
+extern const struct bus_type usb_bus_type;
 extern struct mutex usb_port_peer_mutex;
 extern struct device_type usb_device_type;
 extern struct device_type usb_if_device_type;

drivers/usb/gadget/udc/core.c

···
 
 static DEFINE_IDA(gadget_id_numbers);
 
-static struct bus_type gadget_bus_type;
+static const struct bus_type gadget_bus_type;
 
 /**
  * struct usb_udc - describes one usb device controller
···
 	return 0;
 }
 
-static struct bus_type gadget_bus_type = {
+static const struct bus_type gadget_bus_type = {
 	.name = "gadget",
 	.probe = gadget_bind_driver,
 	.remove = gadget_unbind_driver,

drivers/usb/serial/bus.c

···
 	spin_unlock(&drv->dynids.lock);
 }
 
-struct bus_type usb_serial_bus_type = {
+const struct bus_type usb_serial_bus_type = {
 	.name =		"usb-serial",
 	.match =	usb_serial_device_match,
 	.probe =	usb_serial_device_probe,

drivers/usb/typec/bus.c

···
 	adev->ops = NULL;
 }
 
-struct bus_type typec_bus = {
+const struct bus_type typec_bus = {
 	.name = "typec",
 	.dev_groups = typec_groups,
 	.match = typec_match,

drivers/usb/typec/bus.h

···
 
 #define to_altmode(d) container_of(d, struct altmode, adev)
 
-extern struct bus_type typec_bus;
+extern const struct bus_type typec_bus;
 extern const struct device_type typec_altmode_dev_type;
 
 #define is_typec_altmode(_dev_) (_dev_->type == &typec_altmode_dev_type)

include/linux/usb/serial.h

···
 int usb_serial_bus_register(struct usb_serial_driver *device);
 void usb_serial_bus_deregister(struct usb_serial_driver *device);
 
-extern struct bus_type usb_serial_bus_type;
+extern const struct bus_type usb_serial_bus_type;
 extern struct tty_driver *usb_serial_tty_driver;
 
 static inline void usb_serial_debug_data(struct device *dev,