Re: [PATCH v2] ubifs: fix kconfig dependency warning

[Artem Bityutskiy <dedekind1@gmail.com>]

On Tue, 2011-03-29 at 08:48 -0700, Randy Dunlap wrote:
> On Tue, 29 Mar 2011 18:04:15 +0300 Artem Bityutskiy wrote:
> 
> > On Tue, 2011-03-29 at 08:01 -0700, Randy Dunlap wrote:
> > > On 03/29/11 00:02, Artem Bityutskiy wrote:
> > > > On Mon, 2011-03-28 at 13:40 -0700, Randy Dunlap wrote:
> > > >> From: Randy Dunlap <randy.dunlap@oracle.com>
> > > >>
> > > >> Fix another kconfig dependency warning, this time in ubifs.
> > > >>
> > > >> warning: (UBIFS_FS_DEBUG && LOCKDEP && LATENCYTOP) selects KALLSYMS_ALL which has unmet direct dependencies (DEBUG_KERNEL && KALLSYMS)
> > > >>
> > > >> Without this patch, we can have:
> > > >> # CONFIG_KALLSYMS is not set
> > > >> CONFIG_KALLSYMS_ALL=y
> > > >> which is useless (does nothing unless KALLSYMS is enabled).
> > > >>
> > > >> However, ubifs builds successfully with or without this patch,
> > > >> and it builds with this line completely deleted,
> > > >> so what was this 'select' for?  Just developer convenience?
> > > > 
> > > > Well, here is the idea. You can compile UBIFS with debugging and without
> > > > debugging. Without debugging the resulting ubifs.ko is much smaller, so
> > > > some embedded people prefer it this way.
> > > > 
> > > > If you select debugging support, then we'll compile it a lot of
> > > > assertions, self-checks, test-modes, extra error messages with detailed
> > > > dumps. And we want to see stackdumps when errors or problems happen,
> > > > this is why we select KALLSYMS_ALL.
> > > > 
> > > > So I guess instead we should do:
> > > > 
> > > > select KALLSYMS
> > > > select KALLSYMS_ALL
> > > 
> > > Yes, that should do it.  Thanks for the explanation.
> > 
> > Will you submit a patch? Alternatively, I can make it myself. What is
> > your preference?
> 
> Here's an updated patch.  But since KALLSYMS_ALL depends on DEBUG_KERNEL,
> the lines above aren't quite sufficient and I don't care to select
> DEBUG_KERNEL.

What is the real difference between KALLSYMS_ALL and KALLSYMS? It looks
like for stack dumps KALLSYMS is enough. The Kconfig help text is not
very helpful. And when I look at the help text of
CONFIG_KALLSYMS_EXTRA_PASS I get feeling that this area needs some
clean-up work.

Anyway, any idea why we wouldn't just kill KALLSYMS_ALL by merging it
with KALLSYMS?

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)