From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu Zhao Subject: Re: [PATCH 2/16 v6] PCI: define PCI resource names in an 'enum' Date: Wed, 22 Oct 2008 22:53:59 +0800 Message-ID: <48FF3E87.4090407@uniscape.net> References: <20081022083809.GA3757@yzhao12-linux.sh.intel.com> <200810220824.21356.bjorn.helgaas@hp.com> <48FF3C48.9060809@uniscape.net> <200810220851.13413.bjorn.helgaas@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200810220851.13413.bjorn.helgaas@hp.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Bjorn Helgaas Cc: "randy.dunlap@oracle.com" , "grundler@parisc-linux.org" , "achiang@hp.com" , "matthew@wil.cx" , "linux-pci@vger.kernel.org" , "rdreier@cisco.com" , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "greg@kroah.com" , "mingo@elte.hu" List-Id: virtualization@lists.linuxfoundation.org Bjorn Helgaas wrote: > On Wednesday 22 October 2008 08:44:24 am Yu Zhao wrote: >> Bjorn Helgaas wrote: >>> On Wednesday 22 October 2008 02:40:41 am Yu Zhao wrote: >>>> This patch moves all definitions of the PCI resource names to an 'enum', >>>> and also replaces some hard-coded resource variables with symbol >>>> names. This change eases introduction of device specific resources. >>> Thanks for removing a bunch of magic numbers from the code. >>> >>>> static void >>>> pci_restore_bars(struct pci_dev *dev) >>>> { >>>> - int i, numres; >>>> - >>>> - switch (dev->hdr_type) { >>>> - case PCI_HEADER_TYPE_NORMAL: >>>> - numres = 6; >>>> - break; >>>> - case PCI_HEADER_TYPE_BRIDGE: >>>> - numres = 2; >>>> - break; >>>> - case PCI_HEADER_TYPE_CARDBUS: >>>> - numres = 1; >>>> - break; >>>> - default: >>>> - /* Should never get here, but just in case... */ >>>> - return; >>>> - } >>>> + int i; >>>> >>>> - for (i = 0; i < numres; i++) >>>> + for (i = 0; i < PCI_BRIDGE_RESOURCES; i++) >>>> pci_update_resource(dev, i); >>>> } >>> The behavior of this function used to depend on dev->hdr_type. Now >>> we don't look at hdr_type at all, so we do the same thing for all >>> devices. >>> >>> For example, for a CardBus device, we used to call pci_update_resource() >>> only for BAR 0; now we call it for BARs 0-6. >>> >>> Maybe this is safe, but I can't tell from the patch, so I think you >>> should explain *why* it's safe in the changelog. >> It's safe because pci_update_resource() will ignore unused resources. >> E.g., for a Cardbus, only BAR 0 is used and its 'flags' is set, then >> pci_update_resource() only updates it. BAR 1-6 are ignored since their >> 'flags' are 0. >> >> I'll put more explanation in the changelog. > > This is a logically separate change from merely substituting enum > names for magic numbers, so you might even consider splitting it > into a separate patch. Better bisection and all that, you know :-) Will do. Thanks, Yu