[patch v3 0/3] tty contention resulting from tty_open_by_driver export

[Okash Khawaja]

Hi,

I have updated the patches so that the exclusivity flag is in tty_port.
When closing the struct - by calling tty_release_struct - we also need
to reset the flag. One way to do that is to reset the flag inside
tty_release_struct function, regardless of whether the tty was opened
through tty_kopen or not. In order to keep the code clean, I have
instead created a separate function called tty_kclose which is the same
as tty_release_struct except that it also resets the exclusivity flag.
As a result, any changes to tty_release_struct won't be in tty_kclose
untless manually added. Please advise on this.

Here is a summary of changes when compared to v2:

- Patch 1 uses TTY_PORT_KOPENED flag instead of TTY_KOPENED and as a
        result adds helper functions to read and change the flag
- Patch 1 adds tty_kclose function to close tty opened by tty_kopen
- Patch 2 calls tty_kclose instead of tty_release_struct

Thanks,
Okash