From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:38450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752835AbcFUCAK (ORCPT ); Mon, 20 Jun 2016 22:00:10 -0400 Date: Mon, 20 Jun 2016 20:50:45 -0500 From: Bjorn Helgaas To: Yongji Xie Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, bhelgaas@google.com, alex.williamson@redhat.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, corbet@lwn.net, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, gwshan@linux.vnet.ibm.com Subject: Re: [RESEND PATCH v2 2/4] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources Message-ID: <20160621015045.GB30307@localhost> References: <1464846411-16895-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1464846411-16895-3-git-send-email-xyjxie@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1464846411-16895-3-git-send-email-xyjxie@linux.vnet.ibm.com> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thu, Jun 02, 2016 at 01:46:49PM +0800, Yongji Xie wrote: > Now we use the IORESOURCE_STARTALIGN to identify bridge resources > in __assign_resources_sorted(). That's quite fragile. We can't > make sure that the PCI devices' resources will not use > IORESOURCE_STARTALIGN any more. Can you explain this a little more? I don't quite understand the problem. Maybe you can give an example of the problem? > In this patch, we try to use a more robust way to identify > bridge resources. > > Signed-off-by: Yongji Xie > --- > drivers/pci/setup-bus.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c > index 55641a3..216ddbc 100644 > --- a/drivers/pci/setup-bus.c > +++ b/drivers/pci/setup-bus.c > @@ -390,6 +390,7 @@ static void __assign_resources_sorted(struct list_head *head, > struct pci_dev_resource *dev_res, *tmp_res, *dev_res2; > unsigned long fail_type; > resource_size_t add_align, align; > + int index; > > /* Check if optional add_size is there */ > if (!realloc_head || list_empty(realloc_head)) > @@ -410,11 +411,13 @@ static void __assign_resources_sorted(struct list_head *head, > > /* > * There are two kinds of additional resources in the list: > - * 1. bridge resource -- IORESOURCE_STARTALIGN > - * 2. SR-IOV resource -- IORESOURCE_SIZEALIGN > + * 1. bridge resource > + * 2. SR-IOV resource > * Here just fix the additional alignment for bridge > */ > - if (!(dev_res->res->flags & IORESOURCE_STARTALIGN)) > + index = dev_res->res - dev_res->dev->resource; > + if (index < PCI_BRIDGE_RESOURCES || > + index > PCI_BRIDGE_RESOURCE_END) I think the code looks OK; at least, it seems to match the comment. I'd just like to understand the problem a little better. > continue; > > add_align = get_res_add_align(realloc_head, dev_res->res); > -- > 1.7.9.5 >