Date: Mon, 14 Jul 2008 15:07:31 -0700
From: Randy Dunlap <randy.dunlap@oracle.com>
To: Daniel Guilak <guilak@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, trivial@kernel.org,
       akpm@linux-foundation.org, torvalds@linux-foundation.org,
       daniel@danielguilak.com
Subject: Re: [PATCH] init/version.c: Define version_string only if
 CONFIG_KALLSYMS is not defined.
Message-Id: <20080714150731.e86295b2.randy.dunlap@oracle.com>
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	<1216070438.6497.27.camel@dguilak-desk>
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On Mon, 14 Jul 2008 14:20:38 -0700 Daniel Guilak wrote:

> On Mon, 2008-07-14 at 12:38 -0700, Randy Dunlap wrote:
> > On Mon, 14 Jul 2008 12:04:46 -0700 Daniel Guilak wrote:
> > 
> > > int Version_* is only used with ksymoops, which is only needed (according to
> > > README and Documentation/Changes) if CONFIG_KALLSYMS is NOT defined.  Therefore
> > > this patch defines version_string only if CONFIG_KALLSYMS is not defined.
> > > 
> > > Signed-off-by: Daniel Guilak <daniel@danielguilak.com>
> > > ---
> > >  init/version.c |    2 ++
> > >  1 files changed, 2 insertions(+), 0 deletions(-)
> > > 
> > > Depends on "[PATCH] init/version.c: Silenced sparse warning by declaring the version string."
> > > 
> > > diff --git a/init/version.c b/init/version.c
> > > index 041fd82..52a8b98 100644
> > > --- a/init/version.c
> > > +++ b/init/version.c
> > > @@ -13,11 +13,13 @@
> > >  #include <linux/utsrelease.h>
> > >  #include <linux/version.h>
> > >  
> > > +#ifndef CONFIG_KALLSYMS
> > >  #define version(a) Version_ ## a
> > >  #define version_string(a) version(a)
> > >  
> > >  extern int version_string(LINUX_VERSION_CODE);
> > >  int version_string(LINUX_VERSION_CODE);
> > > +#endif
> > >  
> > >  struct uts_namespace init_uts_ns = {
> > >  	.kref = {
> > > -- 
> > 
> > Does not apply cleanly to linux-2.6.26, linux-next-20080714, or Linus-git-head.
> > 
> 
> Did you apply "[PATCH] init/version.c: Silenced sparse warning by
> declaring the version string." beforehand? I just applied it on the most
> recent tree and I didn't have any issues.

Clearly I didn't apply that patch.  I missed anything saying that this was
patch 2/2 in a dependent series.

> > and why do we ned both extern int version_string()
> > and int version_string() ?
> Because sparse was complaining that it wasn't prototyped or static.
> There isn't a header file to put it in since it only exists to be a
> kernel.

so the extern makes it be published in the symbol table, whereas a static
would keep it private.  Is that correct?

and the second line (int version_string(LINUX_VERSION_CODE)) actually
defines it.

---
~Randy
Linux Plumbers Conference, 17-19 September 2008, Portland, Oregon USA
http://linuxplumbersconf.org/
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