Re: [PATCH 0/1] devpts: use dynamic_dname() to generate proc name

[Linus Torvalds]

On Wed, Aug 23, 2017 at 6:49 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Argh. And it's *not* fairly straightforward, because the
> tty_operations "ioctl()" function pointer only gets 'struct tty *'.
>
> So in the TIOCGPTPEER path, we don't actually have access to the file
> pointer of the fd we're doing the ioctl on.
>
> And that's where the 'struct path' to the 'ptmx' node is - which we
> need to then look up the 'pts' directory.
>
> How very annoying. I think that's why we did it all at ptmx_open()
> time, because then we had all the information.

Anyway, the revert is pushed out. So we're back to the old behavior
that gives the wrong pathname in /proc.

And I think I can handle the lack of a 'struct file *' to the ioctl
operations by just special-casing TIOCGPTPEER directly in tty_ioctl()
itself.

That's where we handle "generic" tty ioctls, and doing pty stuff there
is kind of wrong, but pty's are special.

But I think I'll leave it for tomorrow. So Eric, if you feel like
looking at this, I'd appreciate it.

                Linus