unaddressed issues around tty_open_by_driver

[Okash Khawaja]

On Wed, Jun 28, 2017 at 09:27:56PM +0100, Okash Khawaja wrote:
> Here's what I mean. I've done some rudimentary testing. It seems to
> clean up alright, allowing ttyUSB0 or ttyS0 to be reused by user space
> programs. It also prevents user program from using the tty held by
> speakup while speakup is loaded.
> 
> We don't need tty_kclose though because we can instead call
> tty_release_struct which will free up the tty, removing the need to
> clear TTY_KOPENED flag.
Thinking of raising this on wider mailing list - basically same that we
submitted the patch for exporting tty_open_by_driver to. If that makes
sense.

Thanks,
Okash