From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751766AbdGZOmN (ORCPT <rfc822;w@1wt.eu>);
        Wed, 26 Jul 2017 10:42:13 -0400
Received: from mx1.redhat.com ([209.132.183.28]:50272 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1751495AbdGZOmM (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 26 Jul 2017 10:42:12 -0400
DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C8DF861D37
Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com
Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=pbonzini@redhat.com
Subject: Re: [PATCH v2] smp_call_function: use inline helpers instead of
 macros
To: Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>
Cc: Ralf Baechle <ralf@linux-mips.org>,
        James Hogan <james.hogan@imgtec.com>,
        Paul Burton <paul.burton@imgtec.com>,
        Peter Zijlstra <peterz@infradead.org>, Juergen Gross <jgross@suse.com>,
        Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        linux-mips@linux-mips.org, linux-kernel@vger.kernel.org
References: <20170726133447.2056379-1-arnd@arndb.de>
From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <cc227181-ef9f-dede-d478-ba0714e4bfbb@redhat.com>
Date: Wed, 26 Jul 2017 16:42:07 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.2.1
MIME-Version: 1.0
In-Reply-To: <20170726133447.2056379-1-arnd@arndb.de>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 26 Jul 2017 14:42:12 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 26/07/2017 15:32, Arnd Bergmann wrote:
> A new caller of smp_call_function() passes a local variable as the 'wait'
> argument, and that variable is otherwise unused, so we get a warning
> in non-SMP configurations:
> 
> virt/kvm/kvm_main.c: In function 'kvm_make_all_cpus_request':
> virt/kvm/kvm_main.c:195:7: error: unused variable 'wait' [-Werror=unused-variable]
>   bool wait = req & KVM_REQUEST_WAIT;
> 
> This addresses the warning by changing the two macros into inline functions.
> As reported by the 0day build bot, a small change is required in the MIPS
> r4k code for this, which then gets a warning about a missing variable.
> 
> Fixes: 7a97cec26b94 ("KVM: mark requests that need synchronization")
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Link: https://patchwork.kernel.org/patch/9722063/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

This is not needed anymore, I've fixed it in KVM:

    commit b49defe83659cefbb1763d541e779da32594ab10
    Author: Paolo Bonzini <pbonzini@redhat.com>
    Date:   Fri Jun 30 13:25:45 2017 +0200

    kvm: avoid unused variable warning for UP builds

    The uniprocessor version of smp_call_function_many does not evaluate
    all of its argument, and the compiler emits a warning about "wait"
    being unused.  This breaks the build on architectures for which
    "-Werror" is enabled by default.

    Work around it by moving the invocation of smp_call_function_many to
    its own inline function.

    Reported-by: Paul Mackerras <paulus@ozlabs.org>
    Cc: stable@vger.kernel.org
    Fixes: 7a97cec26b94c909f4cbad2dc3186af3e457a522
    Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Paolo