iucv: make iucv_bus const

Now that the driver core can properly handle constant struct bus_type,
move the iucv_bus variable to be a constant structure as well, placing
it into read-only memory which can not be modified at runtime.

Cc: Wenjia Zhang <wenjia@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: linux-s390@vger.kernel.org
Cc: netdev@vger.kernel.org
Acked-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/iucv/iucv.h

@@ -80,7 +80,7 @@ struct iucv_array {
 	u32 length;
 } __attribute__ ((aligned (8)));
 
-extern struct bus_type iucv_bus;
+extern const struct bus_type iucv_bus;
 extern struct device *iucv_root;
 
 /*
@@ -489,7 +489,7 @@ struct iucv_interface {
 	int (*path_sever)(struct iucv_path *path, u8 userdata[16]);
 	int (*iucv_register)(struct iucv_handler *handler, int smp);
 	void (*iucv_unregister)(struct iucv_handler *handler, int smp);
-	struct bus_type *bus;
+	const struct bus_type *bus;
 	struct device *root;
 };
 

net/iucv/iucv.c

@@ -67,7 +67,7 @@ static int iucv_bus_match(struct device *dev, struct device_driver *drv)
 	return 0;
 }
 
-struct bus_type iucv_bus = {
+const struct bus_type iucv_bus = {
 	.name = "iucv",
 	.match = iucv_bus_match,
 };