Re: linux-next: build failure after merge of the ext4 tree

From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: Sam Ravnborg <sam@ravnborg.org>
Cc: Michal Marek <mmarek@suse.cz>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Steven Rostedt <rostedt@goodmis.org>,
	Kevin Hilman <khilman@linaro.org>,
	sedat.dilek@gmail.com, Theodore Ts'o <tytso@mit.edu>,
	linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
	Linux kbuild ML <linux-kbuild@vger.kernel.org>
Subject: Re: linux-next: build failure after merge of the ext4 tree
Date: Fri, 16 Aug 2013 20:02:40 +0200	[thread overview]
Message-ID: <20130816180240.GA2715@free.fr> (raw)
In-Reply-To: <20130816171448.GA13841@merkur.ravnborg.org>

Sam, Michal, All,

On 2013-08-16 19:14 +0200, Sam Ravnborg spake thusly:
> On Fri, Aug 16, 2013 at 03:10:38PM +0200, Michal Marek wrote:
> > On 11.8.2013 23:39, Yann E. MORIN wrote:
> > > On 2013-08-09 13:42 +0200, Sam Ravnborg spake thusly:
> > >> If we drop the special handling of "MODULES" and introduced
> > >> the following in we may fix it - hopefully:
> > >>
> > >> config MODULES
> > >> 	option modules
> > >>
> > >> The option handling is already in place. It is even documented :-)
> > > 
> > > Yes, indeed, that one is pretty easy! :-)
> > > 
> > >> At least we could then drop the sym_lookup here (zconf.y):
> > >>         if (!modules_sym->prop) {
> > >>                 struct property *prop;
> > >>
> > >>                 prop = prop_alloc(P_DEFAULT, modules_sym);
> > >>                 prop->expr = expr_alloc_symbol(sym_lookup("MODULES", 0));
> > >>         }
> > >> Without the sym_lookup I think the symbol will not be defined and tus not marked valid.
> > > 
> > > Sorry, I don't understand what we should do here.
> > > 
> > > From what I understand, here's what happens:
> > >   - there's no symbol that declared the 'modules' option, so the
> > >     modules_sym->prop is NULL;
> > >   - so we look for the symbol 'MODULES' and use that as the symbol used
> > >     to evaluate if tristates are enabled.
> > > 
> > > So, now we have 'option modules' added to MODULES, we never enter this
> > > if() condition.
> > > 
> > > But what would happen to other projects that do not have a symbol set
> > > with 'option modules' and no 'MODULES' symbol? Surely, those projects do
> > > not need tristates, but what should the code do in this case?
> > > 
> > > So, I don't know what to replace this 'sym_lookup("MODULES", 0)' with.
> > 
> > If the Kconfig files do not provide any symbol with 'option modules',
> > then set modules_sym to a dummy bool with the value 'n'?
> This is my thinking too - to use the symbol "n".
> But I wanted to try it out - but so far have not had time for it.

OK, I'll tackle this. Thanks for the info. :-)

Regards,
Yann E. MORIN.

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