From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030473AbXDJIPS (ORCPT ); Tue, 10 Apr 2007 04:15:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933103AbXDJIOw (ORCPT ); Tue, 10 Apr 2007 04:14:52 -0400 Received: from mga01.intel.com ([192.55.52.88]:2547 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933075AbXDJIOt (ORCPT ); Tue, 10 Apr 2007 04:14:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: i="4.14,389,1170662400"; d="scan'208"; a="227568979:sNHT18805339" Subject: Re: [patch 2/8] [Intel IOMMU] Some generic search functions required to lookup device relationships. From: Shaohua Li To: Greg KH Cc: Ashok Raj , linux-kernel@vger.kernel.org, akpm@osdl.org, ak@suse.de, muli@il.ibm.com, asit.k.mallick@intel.com, suresh.b.siddha@intel.com, anil.s.keshavamurthy@intel.com, arjan@linux.intel.com In-Reply-To: <20070410034617.GA30428@suse.de> References: <20070409215552.221374000@intel.com> <20070409215723.431381000@intel.com> <20070410034617.GA30428@suse.de> Content-Type: text/plain Date: Tue, 10 Apr 2007 16:11:38 +0800 Message-Id: <1176192698.6781.13.camel@sli10-conroe.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2007-04-09 at 20:46 -0700, Greg KH wrote: > On Mon, Apr 09, 2007 at 02:55:54PM -0700, Ashok Raj wrote: > > +/* > > + * find the upstream PCIE-to-PCI bridge of a PCI device > > + * if the device is PCIE, return NULL > > + * if the device isn't connected to a PCIE bridge (that is its parent is a > > + * legacy PCI bridge and the bridge is directly connected to bus 0), return its > > + * parent > > + */ > > +struct pci_dev * > > +pci_find_upstream_pcie_bridge(struct pci_dev *pdev) > > +{ > > + struct pci_dev *tmp = NULL; > > + > > + if (pdev->is_pcie) > > + return NULL; > > + while (1) { > > + if (!pdev->bus->self) > > + break; > > + pdev = pdev->bus->self; > > + /* a p2p bridge */ > > + if (!pdev->is_pcie) { > > + tmp = pdev; > > + continue; > > + } > > + /* PCI device should connect to a PCIE bridge */ > > + BUG_ON(pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE); > > + return pdev; > > + } > > + > > + return tmp; > > +} > > No locking while you walk up the bus list? hmm, iommu driver didn't support pci hotplug in current stage. But we can add lock here. > > --- linux-2.6.21-rc5.orig/include/linux/pci.h 2007-04-03 04:30:51.000000000 -0700 > > +++ linux-2.6.21-rc5/include/linux/pci.h 2007-04-03 06:58:58.000000000 -0700 > > @@ -126,6 +126,7 @@ > > unsigned short subsystem_device; > > unsigned int class; /* 3 bytes: (base,sub,prog-if) */ > > u8 hdr_type; /* PCI header type (`multi' flag masked out) */ > > + u8 pcie_type; /* PCI-E device/port type */ > > u8 rom_base_reg; /* which config register controls the ROM */ > > u8 pin; /* which interrupt pin this device uses */ > > > > @@ -168,6 +169,7 @@ > > unsigned int msi_enabled:1; > > unsigned int msix_enabled:1; > > unsigned int is_managed:1; > > + unsigned int is_pcie:1; > > Do you really need both fields? Wouldn't just the pcie_type one work > (with some NOT_PCIE type being set for it if it isn't I suppose.) There are some encodings are reserved for future. Just don't want to use reserved bits, as we don't know which one is proper for NOT_PCIE. Thanks, Shaohua