Re: 2.6.5-rc3-mm1

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Tue, Mar 30, 2004 at 06:26:27PM -0800, Andrew Morton wrote:
> Andrew Morton <akpm@osdl.org> wrote:
> >
> > I'm thinking that this can be fixed from the other direction: just before
> >  release_dev() calls close (dropping BKL), if tty->count==1, make the
> >  going-away tty ineligible for concurrent lookups.  Do that by setting
> >  tty->driver->ttys[idx] to NULL.  Maybe.
> 
> Famous last word: Volia!

I suspect you may just be able to get away with this for serial drivers
using serial_core.  However, I suspect it'll break non-serial_core using
serial drivers.

The serial drivers track the tty count themselves, so that they know
when to do the final close processing (why you may ask - because of
the blocking for DCD in the open code.)  I wouldn't like to say what
would happen if ->open were called for a different tty structure for
the same port while ->close was in progress.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core