From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [PATCH] x86/kexec: crash_vmclear_local_vmcss needs __rcu Date: Mon, 10 Dec 2012 18:30:14 -0200 Message-ID: <20121210203014.GB2402@amt.cnet> References: <50C18168.305@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Eric W. Biederman" , Gleb Natapov , "kvm@vger.kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , kbuild test robot To: Zhang Yanfei Return-path: Content-Disposition: inline In-Reply-To: <50C18168.305@cn.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Fri, Dec 07, 2012 at 01:40:56PM +0800, Zhang Yanfei wrote: > This removes the sparse warning: > arch/x86/kernel/crash.c:49:32: sparse: incompatible types in comparison expression (different address spaces) > > Reported-by: kbuild test robot > Signed-off-by: Zhang Yanfei > --- > arch/x86/include/asm/kexec.h | 4 +++- > arch/x86/kernel/crash.c | 4 ++-- > 2 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h > index 28feeba..16882cd 100644 > --- a/arch/x86/include/asm/kexec.h > +++ b/arch/x86/include/asm/kexec.h > @@ -163,7 +163,9 @@ struct kimage_arch { > }; > #endif > > -extern void (*crash_vmclear_loaded_vmcss)(void); > +extern void __rcu (*crash_vmclear_loaded_vmcss)(void); > +#define vmclear_func_rcu(vmclear_func) \ > + ((void (*)(void)) rcu_dereference(vmclear_func)) > > #endif /* __ASSEMBLY__ */ > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index 2f6b8e8..50ce1d6 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -38,7 +38,7 @@ int in_crash_kexec; > * > * protected by rcu. > */ > -void (*crash_vmclear_loaded_vmcss)(void) = NULL; > +void __rcu (*crash_vmclear_loaded_vmcss)(void) = NULL; Isnt this (__rcu AS tag) sufficient? After all, sparse is complaining about namespaces. Creating a #define to cast seems excessive.