Header organization/separation rule in kernel

Hi, I wonder the header separation rule in kernel. To make this question concrete, for example, let's targeting genetlink.h It can be found in: http://elixir.free-electrons.com/linux/latest/source/include/net/genetlink.h http://elixir.free-electrons.com/linux/latest/source/include/linux/genetlink... http://elixir.free-electrons.com/linux/latest/source/include/uapi/linux/gene... so basically three parts, in uapi, linux/genetlink.h, and net/genetlink.h. I understand the necessity of uapi, but why divide the genetlink.h in linux and the net folder? What's the benefit of such separation? -- Best, Shiyao