[patch 1/6] tty_port: allow a port to be opened with a tty that has no file handle

[Samuel Thibault]

Okash Khawaja, on mar. 23 mai 2017 09:30:34 +0100, wrote:
> Here's quote:
> 
>     "It doesn't deal with the case of a user opening a port that's also kernel
>     opened and that would need some locking out (so it returned EBUSY if bound
>     to a kernel device of some kind)."

Ah, ok, so that doesn't exist yet and needs to be added. Something like
a flag added to the tty structure, which is set and cleared when opening
and closing the device from the kernel.

> > AFAICS, tty_open() will just always manage to open
> > the tty, and reach the check_tty_count() call.
> Yes. Wonder if that is okay then or do we need to do something about it?

On the contrary, that the problem: we don't want it to reach
check_tty_count(), since that's what warns out.

Samuel