Re: [Linaro-mm-sig] Re: [PATCH] epoll: try to be a _bit_ better about file lifetimes

[Linus Torvalds <torvalds@linux-foundation.org>]

On Tue, 7 May 2024 at 11:04, Daniel Vetter <daniel@ffwll.ch> wrote:
>
> On Tue, May 07, 2024 at 09:46:31AM -0700, Linus Torvalds wrote:
>
> > I'd be perfectly ok with adding a generic "FISAME" VFS level ioctl
> > too, if this is possibly a more common thing. and not just DRM wants
> > it.
> >
> > Would something like that work for you?
>
> Yes.
>
> Adding Simon and Pekka as two of the usual suspects for this kind of
> stuff. Also example code (the int return value is just so that callers know
> when kcmp isn't available, they all only care about equality):
>
> https://gitlab.freedesktop.org/mesa/mesa/-/blob/main/src/util/os_file.c#L239

That example thing shows that we shouldn't make it a FISAME ioctl - we
should make it a fcntl() instead, and it would just be a companion to
F_DUPFD.

Doesn't that strike everybody as a *much* cleaner interface? I think
F_ISDUP would work very naturally indeed with F_DUPFD.

Yes? No?

                       Linus