From patchwork Tue May 13 01:35:22 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 348202 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 746C6140087 for ; Tue, 13 May 2014 11:36:01 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753920AbaEMBfh (ORCPT ); Mon, 12 May 2014 21:35:37 -0400 Received: from e23smtp06.au.ibm.com ([202.81.31.148]:35430 "EHLO e23smtp06.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754392AbaEMBff (ORCPT ); Mon, 12 May 2014 21:35:35 -0400 Received: from /spool/local by e23smtp06.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 13 May 2014 11:35:33 +1000 Received: from d23dlp02.au.ibm.com (202.81.31.213) by e23smtp06.au.ibm.com (202.81.31.212) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 13 May 2014 11:35:31 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 34CF62BB0047; Tue, 13 May 2014 11:35:31 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s4D1EEO035454986; Tue, 13 May 2014 11:14:14 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s4D1ZUZh011695; Tue, 13 May 2014 11:35:30 +1000 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.190.163.12]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s4D1ZU2Q011692; Tue, 13 May 2014 11:35:30 +1000 Received: from shangw (haven.au.ibm.com [9.190.164.82]) by ozlabs.au.ibm.com (Postfix) with ESMTP id D5A7BA0194; Tue, 13 May 2014 11:35:29 +1000 (EST) Received: by shangw (Postfix, from userid 1000) id 121783E3129; Tue, 13 May 2014 11:35:30 +1000 (EST) From: Gavin Shan To: kvm@vger.kernel.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, linux-pci@vger.kernel.org, Gavin Shan Subject: [PATCH 2/4] drivers/vfio: Rework offsetofend() Date: Tue, 13 May 2014 11:35:22 +1000 Message-Id: <1399944924-1200-3-git-send-email-gwshan@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1399944924-1200-1-git-send-email-gwshan@linux.vnet.ibm.com> References: <1399944924-1200-1-git-send-email-gwshan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051301-7014-0000-0000-000004E07686 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org The macro offsetofend() introduces unnecessary temporary variable "tmp". The patch avoids that and saves a bit memory in stack. Signed-off-by: Gavin Shan --- include/linux/vfio.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 81022a52..8ec980b 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -86,9 +86,8 @@ extern void vfio_unregister_iommu_driver( * from user space. This allows us to easily determine if the provided * structure is sized to include various fields. */ -#define offsetofend(TYPE, MEMBER) ({ \ - TYPE tmp; \ - offsetof(TYPE, MEMBER) + sizeof(tmp.MEMBER); }) \ +#define offsetofend(TYPE, MEMBER) \ + (offsetof(TYPE, MEMBER) + sizeof(((TYPE *)0)->MEMBER)) /* * External user API