From patchwork Mon May 19 03:01:08 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gavin Shan X-Patchwork-Id: 4198961 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 81418BEEAB for ; Mon, 19 May 2014 03:01:26 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id BF28120274 for ; Mon, 19 May 2014 03:01:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4E2A201FA for ; Mon, 19 May 2014 03:01:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752572AbaESDBV (ORCPT ); Sun, 18 May 2014 23:01:21 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:44420 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751897AbaESDBS (ORCPT ); Sun, 18 May 2014 23:01:18 -0400 Received: from /spool/local by e23smtp05.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 19 May 2014 13:01:17 +1000 Received: from d23dlp03.au.ibm.com (202.81.31.214) by e23smtp05.au.ibm.com (202.81.31.211) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Mon, 19 May 2014 13:01:15 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id CCCA83578052; Mon, 19 May 2014 13:01:14 +1000 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s4J2dfmP61210836; Mon, 19 May 2014 12:39:41 +1000 Received: from d23av02.au.ibm.com (localhost [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s4J31DRm013361; Mon, 19 May 2014 13:01:14 +1000 Received: from ozlabs.au.ibm.com (ozlabs.au.ibm.com [9.190.163.12]) by d23av02.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s4J31DwN013354; Mon, 19 May 2014 13:01:13 +1000 Received: from shangw (haven.au.ibm.com [9.190.164.82]) by ozlabs.au.ibm.com (Postfix) with ESMTP id 7D5D1A011B; Mon, 19 May 2014 13:01:13 +1000 (EST) Received: by shangw (Postfix, from userid 1000) id C3C713E0291; Mon, 19 May 2014 13:01:13 +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: Mon, 19 May 2014 13:01:08 +1000 Message-Id: <1400468470-11262-3-git-send-email-gwshan@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1400468470-11262-1-git-send-email-gwshan@linux.vnet.ibm.com> References: <1400468470-11262-1-git-send-email-gwshan@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14051903-1396-0000-0000-000004DCEA87 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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