Re: [RFC] new module format

[Roman Zippel <zippel@linux-m68k.org>]

Hi,

On Wed, 17 Jul 2002, Daniel Phillips wrote:

> > 1. Properly fixing module races: I'm playing with a init/start/stop/exit
> > model, this has the advantage that we can stop anyone from reusing a
> > module and we only have to wait for remaining users to go away until we
> > can safely unload the module.
>
> I'm satisfied that, for filesystems at least, all the module races can be
> solved without adding start/stop, and I will present code in due course.

The start/stop methods are not needed to fix the races, they allow better
control of the unload process.

> However, Rusty tells me there are harder cases than filesystems.  At this
> point I'm waiting for a specific example.

For filesystems it's only simpler because they only have a single entry
point, but the basic problem is always the same. We have to protect
against module load/unload and unregister. Without an interface change we
will have to add module owner pointers everywhere and we will see
contention on the unload_lock due to try_inc_mod_count.

bye, Roman