From mboxrd@z Thu Jan 1 00:00:00 1970 From: Josh Triplett Subject: Re: [BUG report]sparse warnings on DEFINE_PER_CPU() symbols non-static Date: Tue, 3 Dec 2013 15:43:20 -0800 Message-ID: <20131203234320.GA15141@jtriplet-mobl1> References: <5294175F.2080407@cn.fujitsu.com> <20131203222543.GQ8277@htj.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from relay5-d.mail.gandi.net ([217.70.183.197]:54151 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753201Ab3LCXnc (ORCPT ); Tue, 3 Dec 2013 18:43:32 -0500 Content-Disposition: inline In-Reply-To: <20131203222543.GQ8277@htj.dyndns.org> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Tejun Heo Cc: Wanlong Gao , linux-sparse@vger.kernel.org, Wu Fengguang , kbuild-all@01.org, Rusty Russell , Christoph Lameter On Tue, Dec 03, 2013 at 05:25:43PM -0500, Tejun Heo wrote: > Hello, > > On Tue, Nov 26, 2013 at 11:37:03AM +0800, Wanlong Gao wrote: > > If kernel config CONFIG_DEBUG_FORCE_WEAK_PER_CPU=y, then the sparse will report non-static > > warnings like following: > > > > > /git/linux/fs/inode.c:74:8: warning: symbol 'nr_inodes' was not declared. Should it be static? > > > /git/linux/fs/inode.c:75:8: warning: symbol 'nr_unused' was not declared. Should it be static? > > > > > > $ vi +74 fs/inode.c > > > 73 > > > 74 static DEFINE_PER_CPU(unsigned long, nr_inodes); > > > 75 static DEFINE_PER_CPU(unsigned long, nr_unused); > > > 76 > > Hmmm, so, if FORCE_WEAK_PER_CPU is set or the arch needs WEAK_PER_CPU, > DEFINE_PER_CPU() explodes into mind-bending series of definitions to > ensure that the symbol is globally unique to avoid breaking weak decl > requirements on a few archs. In the process static is dropped from > the actual declaration and it's apparently missing extern decl in > front of it. > > Does the following patch make it go away? It should, but is there some reason why you couldn't make the definition on the line immediately below that static? > Thanks. > > diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h > index 57e890a..8c490cc 100644 > --- a/include/linux/percpu-defs.h > +++ b/include/linux/percpu-defs.h > @@ -69,6 +69,7 @@ > __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \ > extern __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \ > __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \ > + extern __typeof__(type) name; \ > __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak \ > __typeof__(type) name > #else > -- > To unsubscribe from this list: send the line "unsubscribe linux-sparse" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html