[PATCH tty-next 14/22] tty: Remove tty_wait_until_sent_from_close()
One Thousand Gnomes
gnomes at lxorguk.ukuu.org.uk
Fri Oct 10 19:58:28 EST 2014
> 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
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