Re: [2.6 patch] make UNIX a bool

From: James C. Georgas
Date: Mon Mar 06 2006 - 18:39:51 EST


On Sat, 2006-04-03 at 17:57 -0500, Kyle Moffett wrote:
> On Mar 3, 2006, at 16:31:51, James C. Georgas wrote:
> > On Thu, 2006-02-03 at 23:32 -0500, Kyle Moffett wrote:
> >> af_unix (IE: CONFIG_UNIX) currently uses the symbol
> >> get_max_files. It is the only module that uses that symbol, and
> >> that symbol probably should not be exported as it's kind of an
> >> internal API. Therefore if we mandate that CONFIG_UNIX != m, then
> >> that symbol may be properly unexported and made private, because
> >> nothing modular would use it. Does that clear things up?
> >
> > Yes, I think I understand.
> >
> > However, even if you don't export the symbol, I don't see how you
> > can make it private (i.e. static declaration) to file_table.c,
> > since it has to remain extern, in order to be visible to af_unix.c.
>
> You're missing some crucial information about how Linux operates.
> EXPORT_SYMBOL != extern. Basically, Linux maintains a list of
> symbols that dynamically loaded modules are allowed to use, along
> with some technical usage restrictions on each (Symbols exported
> with EXPORT_SYMBOL_GPL may only be used by modules that declare
> 'MODULE_LICENSE("GPL");'.) Exporting a symbol increases the
> likliehood that some module author will use it inappropriately, and
> bloats the kernel. In this case, removing the EXPORT_SYMBOL() would
> be a good thing.

Isn't it kind of pointless to not EXPORT a symbol if the symbol is still
declared globally in an include/linux/ header file? If the intent is to
prevent abuse of the symbol, then this doesn't do it, because I can just
statically compile my module into the kernel, and keep on using that
symbol.

It makes sense to me to remove the EXPORT of geget_max_filest_max_files,
if the intent is to eventually remove




I was under the impression that Adrian wanted
>
> Cheers,
> Kyle Moffett
>
--
James C. Georgas <jgeorgas@xxxxxxxxxx>

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