[PATCH tty-next 14/22] tty: Remove tty_wait_until_sent_from_close()

[One Thousand Gnomes]

> The point being that holding the tty lock across the _entire_ close
> is equivalent to the current outcome, regardless of O_NONBLOCK.
> 
> I'm reluctant to start returning EGAIN for non-blocking tty opens
> because no tty driver does that now, and I don't think userspace will
> deal well with new return codes from tty opens.

I do not know about the non blocking case mattering. The blocking open
does need to wait, when I broke that case before I broke the console
login drivers (mingetty).

Returning EAGAIN would also only work if poll/select did the right thing.
Currently Linux can't support a System5 style ttymon process because of
this limitation, which means, for example, that systemd can't implement a
single thread to manage all console prompts/setup

Alan