Re: 2.6.12-rc2-mm2

From: Paul E. McKenney
Date: Tue Apr 12 2005 - 20:42:33 EST


On Wed, Apr 13, 2005 at 02:36:04AM +0200, Adrian Bunk wrote:
> On Mon, Apr 11, 2005 at 08:18:32AM -0700, Paul E. McKenney wrote:
> > On Mon, Apr 11, 2005 at 12:48:34AM +0200, Adrian Bunk wrote:
> > > kernel-rcupdatec-make-the-exports-export_symbol_gpl.patch
> > > add-deprecated_for_modules.patch
> > > add-deprecated_for_modules-fix.patch
> > > deprecate-synchronize_kernel-gpl-replacement.patch
> > > deprecate-synchronize_kernel-gpl-replacement-fix.patch
> > > change-synchronize_kernel-to-_rcu-and-_sched.patch
> > >
> > >
> > > Please drop these patches.
> >
> > Please keep them!
> >
> > > Using these symbols in non-GPL modules is a legal problem at least in
> > > the USA except for IBM,
> >
> > Again, based on what line of reasoning? Again, the obvious lines
> > of reasoning do not apply.
>
> Shouldn't the IBM patents be enough reason to prevent everyone except
> IBM from using RCU in non-GPL modules?

Not necessarily, at least according to the lawyers that I talk to.

> > > and all we've heard from IBM is that they are
> > > not 100% sure that there is really no binary-only module by IBM that
> > > might use these symbols.
> >
> > >From my earlier message (http://lkml.org/lkml/2005/4/4/244):
> >
> > Agreed, in that I know of no binary module that uses RCU. However,
> > I cannot -prove- that there is no such module.
> >
> > IOW, I am also not 100% sure that there is really no binary-only module
> > using these symbols by -anyone-, including someone -other- than IBM.
> > In addition, I know of no way that -anyone- could possibly be 100% sure
> > that there is really no binary-only module using symbols. Hence the
> > approach of providing the year "grace period" before transitioning to
> > EXPORT_SYMBOL_GPL().
> >...
>
> If kernel development was based on the assumption that every change that
> might break binary-only modules would need a one year "grace period", it
> was much different from how it's today...

This is not "every change", but a specific change, and a rather unusual
one at that.

Thanx, Paul

> cu
> Adrian
>
> --
>
> "Is there not promise of rain?" Ling Tan asked suddenly out
> of the darkness. There had been need of rain for many days.
> "Only a promise," Lao Er said.
> Pearl S. Buck - Dragon Seed
>
>
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