Re: EXPORT_NO_SYMBOLS vs. (null) ?

[Jeff Garzik <jgarzik@mandrakesoft.com>]

Rogier Wolff wrote:
> 
> Jeff Garzik wrote:
> > Rogier Wolff wrote:
> > >
> > > Alan Cox wrote:
> > > > > What is the difference between a module that exports no symbols and
> > > > > includes EXPORT_NO_SYMBOLS reference, and such a module that lacks
> > > > > EXPORT_NO_SYMBOLS?
> > > > >
> > > > > Alan once upbraided me for assuming they were the same :)
> > > >
> > > > EXPORT_NO_SYMBOLS             -       nothing exported
> > > > MODULE_foo                    -       export specific symbol
> > > >
> > > > none of the above, export all globals but without modvers
> > >                                 ^^^^^^^ and statics!!!!
> > >
> > > I consider that a bug, but...
> >
> > eh?  Can you give an example of this?  This should definitely -not- be
> > the case.
> 
> Compile a kernel, marking "sx" and "riscom8" as modules.
> 
> Install, modprobe sx, and voila, you'll pull in the riscom because
> its "block_til_ready" static was found to satisfy the block_til_ready
> from generic_serial.

That doesn't imply that statics are being exported as symbols. 
generic_serial had no EXPORT_xxx markers, and block_til_ready was
public, so it was expected behavior for g_s to export b_t_r as a symbol.

It is strange that a static which exists in riscom8 causes another
module which exports the same symbol to be pulled in.

> We're working on renaming the one in generic_serial to
> "gs_block_til_ready", but haven't checked yet if the patch got
> applied. So you may have to use a "month-old" kernel for this test.

Can this function be made static?  It looks like many drivers define it
themselves..

In any case, you have a patch coming to you [offline] cleaning up the sx
and riscom8 namespaces...

	Jeff


-- 
Jeff Garzik             |
Building 1024           | The chief enemy of creativity is "good" sense
MandrakeSoft            |          -- Picasso
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