Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759428Ab3EOPIA (ORCPT ); Wed, 15 May 2013 11:08:00 -0400 Received: from mail-pb0-f51.google.com ([209.85.160.51]:52826 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755811Ab3EOPH6 (ORCPT ); Wed, 15 May 2013 11:07:58 -0400 Message-ID: <5193A4C7.1040607@gmail.com> Date: Wed, 15 May 2013 23:07:51 +0800 From: Liu Jiang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130404 Thunderbird/17.0.5 MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: Bjorn Helgaas , Yinghai Lu , Jiang Liu , "Rafael J . Wysocki" , Greg Kroah-Hartman , Gu Zheng , Toshi Kani , Myron Stowe , Yijing Wang , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Paul Mackerras , Gavin Shan , Grant Likely , Bill Pemberton , linuxppc-dev@lists.ozlabs.org Subject: Re: [RFC PATCH v2, part 2 09/18] PCI, PPC: use hotplug-safe iterators to walk PCI buses References: <1368550322-1045-1-git-send-email-jiang.liu@huawei.com> <1368550322-1045-9-git-send-email-jiang.liu@huawei.com> <1368574202.31689.54.camel@pasglop> In-Reply-To: <1368574202.31689.54.camel@pasglop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2260 Lines: 69 On 05/15/2013 07:30 AM, Benjamin Herrenschmidt wrote: > On Wed, 2013-05-15 at 00:51 +0800, Jiang Liu wrote: >> Enhance PPC architecture specific code to use hotplug-safe iterators >> to walk PCI buses. > I was about to ack it but then I saw: > >> diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c >> index 51a133a..a41c6dd 100644 >> --- a/arch/powerpc/kernel/pci_64.c >> +++ b/arch/powerpc/kernel/pci_64.c >> @@ -208,7 +208,6 @@ long sys_pciconfig_iobase(long which, unsigned long in_bus, >> unsigned long in_devfn) >> { >> struct pci_controller* hose; >> - struct list_head *ln; >> struct pci_bus *bus = NULL; >> struct device_node *hose_node; >> >> @@ -229,18 +228,16 @@ long sys_pciconfig_iobase(long which, unsigned long in_bus, >> /* That syscall isn't quite compatible with PCI domains, but it's >> * used on pre-domains setup. We return the first match >> */ >> - >> - for (ln = pci_root_buses.next; ln != &pci_root_buses; ln = ln->next) { >> - bus = pci_bus_b(ln); >> - if (in_bus >= bus->number && in_bus <= bus->busn_res.end) >> + for_each_pci_root_bus(bus) >> + if (in_bus >= bus->number && in_bus <= bus->busn_res.end && >> + bus->dev.of_node) >> break; >> - bus = NULL; >> - } >> - if (bus == NULL || bus->dev.of_node == NULL) >> + if (bus == NULL) >> return -ENODEV; > You just removed the NULL check for the of_node field... Hi Benjamin, Thanks for review. I just moved the "bus->dev.of_node == NULL" into the above for_each_pci_root_bus() loop:) Will send you another version according to your suggestion to use pci_bus_to_host() to simplify the code. Regards! Gerry > >> hose_node = bus->dev.of_node; >> hose = PCI_DN(hose_node)->phb; > Which is dereferrenced here. > >> + pci_bus_put(bus); > On the other hand, the whole thing can probably be using > pci_bus_to_host() instead.... the above code is bitrotted. > >> switch (which) { >> case IOBASE_BRIDGE_NUMBER: > > Cheeers, > Ben. > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/