Re: [RFC] add module reference to struct tty_driver

[Greg KH <greg@kroah.com>]

On Mon, Jan 13, 2003 at 09:27:34AM +0000, Russell King wrote:
> On Sun, Jan 12, 2003 at 09:47:09PM -0800, Greg KH wrote:
> > In digging into the tty layer locking, I noticed that the tty layer
> > doesn't handle module reference counting for any tty drivers.  Well, I've
> > known this for a long time, just finally got around to fixing it :)
> > Here's a patch against 2.5.56 that should fix this issue (works for
> > me...)
> > 
> > Comments?  If no one objects, I'll send it on to Linus, and add support
> > for this to a number of tty drivers that commonly get built as modules.
> 
> I'd just ask whether you considered what happens when:
> 
> 1. two people open the same tty
> 2. the tty is hung up
> 3. both people close the tty
> 
> (this isn't an indication that the patch is wrong, I'm just interested
> to know.)

It "should" work with the above situation, as we only decrement the
module count when the tty device structure that is bound to a driver is
freed, and increment it when it is created.  So if those functions work
properly with regards to memory management, the module reference
counting should also work.

Hm, well I hope so at least :)

Let me know if your tests show up any problems.

thanks,

gregk -h