Messages in this thread | | | Subject | Re: [2.6 patch] make UNIX a bool | From | "James C. Georgas" <> | Date | Mon, 06 Mar 2006 18:59:14 -0500 |
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Excuse me - sent half a response earlier.
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 get_max_files only if the intent is to eventually remove the get_max_files function from include/linux/fs.h.
This would require that af_unix.c calculate the maximum number of allowed open Unix sockets from information other than the files_stat.max_files value is fs/file_table.c.
If that's the intent, then there's no point in disallowing AF_UNIX=m. Doing this just so one can unEXPORT a symbol only fixes half the issue.
> Cheers, > Kyle Moffett > -- James C. Georgas <jgeorgas@rogers.com>
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