Re: [PATCH] uapi: avoid namespace conflict in linux/posix_types.h

From: Linus Torvalds
Date: Mon Jun 17 2019 - 13:55:03 EST

On Mon, Jun 17, 2019 at 4:45 AM Florian Weimer <fweimer@xxxxxxxxxx> wrote:
> I wanted to introduce a new header, <asm/kernel_long_t.h>, and include
> it where the definition of __kernel_long_t is needed, something like
> this (incomplete, untested):

So this doesn't look interesting to me: __kernel_long_t is neither
interesting as a type anyway (it's just a way for user space to
override "long"), nor is it a namespace violation.

So honestly, user space could do whatever it wants for __kernel_long_t anyway.

The thing that I think we should try to fix is just the "val[]" thing, ie

> A different approach would rename <asm/posix_types.h> to something more
> basic, exclude the two structs, and move all internal #includes which do
> need the structs to the new header.

In fact, I wouldn't even rename <posix_types.h> at all, I'd just make
sure it's namespace-clean.

I _think_ the only thing causing problems is '__kernel_fsid_t' due to
that "val[]" thing, so just remove ity entirely, and add it to
<statfs.h> instead.

And yeah, then we'd need to maybe make sure that the (couple) of
__kernel_fsid_t users properly include that statfs.h file.