Linux kernel: why do 'subclass' structs put base class info at end?

Question

I was reading the chapter in Beautiful Code on the Linux kernel and the author discusses how Linux kernel implements inheritance in the C language (amongst other topics). In a

Answer 1

It's for multiple inheritance. struct dev isn't the only interface you can apply to a struct in the linux kernel, and if you have more than one, just casting the sub class to a base class wouldn't work. For example:

struct device {
     int a;
     int b;
     // etc...
};

struct asdf {
   int asdf_a;
};

struct usb_device {
    int usb_a;
    int usb_b;
    struct device dev;
    struct asdf asdf;
};