From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752890AbZCIIMu (ORCPT ); Mon, 9 Mar 2009 04:12:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751940AbZCIIMe (ORCPT ); Mon, 9 Mar 2009 04:12:34 -0400 Received: from mga02.intel.com ([134.134.136.20]:13542 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751796AbZCIIMd (ORCPT ); Mon, 9 Mar 2009 04:12:33 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.38,328,1233561600"; d="scan'208";a="496174710" Date: Mon, 9 Mar 2009 16:13:37 +0800 From: Yu Zhao To: Matthew Wilcox Cc: "jbarnes@virtuousgeek.org" , "linux-pci@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v10 3/7] PCI: reserve bus range for SR-IOV device Message-ID: <20090309081337.GB4638@yzhao-otc.sh.intel.com> References: <1235112888-9524-1-git-send-email-yu.zhao@intel.com> <1235112888-9524-4-git-send-email-yu.zhao@intel.com> <20090306202024.GF25995@parisc-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090306202024.GF25995@parisc-linux.org> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 07, 2009 at 04:20:24AM +0800, Matthew Wilcox wrote: > On Fri, Feb 20, 2009 at 02:54:44PM +0800, Yu Zhao wrote: > > +static inline void virtfn_bdf(struct pci_dev *dev, int id, u8 *busnr, u8 *devfn) > > +{ > > + u16 bdf; > > + > > + bdf = (dev->bus->number << 8) + dev->devfn + > > + dev->sriov->offset + dev->sriov->stride * id; > > + *busnr = bdf >> 8; > > + *devfn = bdf & 0xff; > > +} > > I find the interface here a bit clunky -- a function returning void > while having two OUT parameters. How about this variation on the theme > (viewers are encouraged to come up with their own preferred > implementations and interfaces): > > static inline __pure u16 virtfn_bdf(struct pci_dev *dev, int id) > { > return (dev->bus->number << 8) + dev->devfn + dev->sriov->offset + > dev->sriov->stride * id; > } > > #define VIRT_BUS(dev, id) (virtfn_bdf(dev, id) >> 8) > #define VIRT_DEVFN(dev, id) (virtfn_bdf(dev, id) & 0xff) > > We rely on GCC to do CSE and not actually invoke virtfn_bdf more than > once. Yes, that's a good idea. Will replace that function with macros.