RE: [PATCH] serial: 8250: Add cpufreq support

From: Shankarmurthy, Akshay
Date: Tue Apr 17 2012 - 05:44:03 EST


On Thu, Apr 12, 2012 at 15:17:58, Alan Cox wrote:
> > > > I will have a look at this and add the lock if necessary.
> > >
> > > At the very least you need reference counts held on the tty struct and to allow for the tty having vanished under you.
> > >
> >
> > I am planning to add "tty->termios_mutex" lock. Any comments ?
>
> Explain how this will help. You need a reference count to the tty itself.
>


I have gone through the serial driver, still I am not able to figure out the requirement
of tty reference count here. Correct me if I am wrong.
As per my understanding, tty count keeps the count of tty_open and tty_release, that is
how many open and close happened on the tty device file(/dev/ttyS*).
The requirement here is a tty count check, if it is greater than zero then only it should
proceed for further execution.
Kindly elaborate more on the same if it's not correct.

>
> Alan
>

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