From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755870AbbCCJcL (ORCPT ); Tue, 3 Mar 2015 04:32:11 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:50306 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752921AbbCCJcH (ORCPT ); Tue, 3 Mar 2015 04:32:07 -0500 Message-ID: <54F57F80.6050205@huawei.com> Date: Tue, 3 Mar 2015 17:31:44 +0800 From: Yijing Wang User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Bjorn Helgaas CC: Jiang Liu , , Yinghai Lu , , Marc Zyngier , , Russell King , , Thomas Gleixner , Benjamin Herrenschmidt , Rusty Russell , Tony Luck , , "David S. Miller" , "Guan Xuetao" , , , Liviu Dudau , "Arnd Bergmann" , Geert Uytterhoeven , "Yijing Wang" , "James E.J. Bottomley" , Subject: Re: [PATCH v4 22/30] PCI/Parisc: Use pci_scan_root_bus() for simplicity References: <1424938344-4017-1-git-send-email-wangyijing@huawei.com> <1424938344-4017-23-git-send-email-wangyijing@huawei.com> <20150303032412.GK11978@google.com> In-Reply-To: <20150303032412.GK11978@google.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.27.212] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/3/3 11:24, Bjorn Helgaas wrote: > On Thu, Feb 26, 2015 at 04:12:16PM +0800, Yijing Wang wrote: >> From: Yijing Wang > > When you write subject lines, I think it's friendly to run > "git log --oneline" on the file you're changing, and make yours > match the previous ones. > > $ git log --oneline drivers/parisc/dino.c > 3f05536d226d PCI/Parisc: Use pci_scan_root_bus() for simplicity > 3335f75a8877 parisc: dino: fix %d confusingly prefixed with 0x in format string > 3fad9b8d597f drivers/parisc: Use printf extension %pR for struct resource > 0fe763c570ad Drivers: misc: remove __dev* attributes. > 0b79ca2a800d parisc/PCI: Use list_for_each_entry() for bus->devices traversal > 30aa80da43a5 parisc/PCI: register busn_res for root buses > ... > > Yours doesn't match any of them, but "parisc/PCI" seems the best match. OK, I will refresh the title, sorry. > >> Now pci_bus_add_devices() has been ripped out >> from pci_scan_root_bus(), we could use pci_scan_root_bus() >> instead of pci_create_root_bus() + pci_scan_child_bus() >> for simplicity. We could also remove the pci bus >> resource(dino_current_bus,255) and pci_bus_update_busn_res_end(), >> because pci_scan_root_bus() would do the same thing. >> >> Signed-off-by: Yijing Wang >> CC: "James E.J. Bottomley" >> CC: linux-parisc@vger.kernel.org >> --- >> drivers/parisc/dino.c | 11 ++--------- >> drivers/parisc/lba_pci.c | 7 ++----- >> 2 files changed, 4 insertions(+), 14 deletions(-) >> >> diff --git a/drivers/parisc/dino.c b/drivers/parisc/dino.c >> index a0580af..e5ee339 100644 >> --- a/drivers/parisc/dino.c >> +++ b/drivers/parisc/dino.c >> @@ -977,15 +977,11 @@ static int __init dino_probe(struct parisc_device *dev) >> if (dino_dev->hba.gmmio_space.flags) >> pci_add_resource(&resources, &dino_dev->hba.gmmio_space); >> >> - dino_dev->hba.bus_num.start = dino_current_bus; >> - dino_dev->hba.bus_num.end = 255; >> - dino_dev->hba.bus_num.flags = IORESOURCE_BUS; >> - pci_add_resource(&resources, &dino_dev->hba.bus_num); > > I know pci_scan_root_bus() does default to bus 0-255, but I don't really > like that behavior, and I think it's a bug for drivers like this to rely on > that. The PCI core has no way to discover the actual bus number range, and > the only reason it supplies a default is because it was inconvenient to > change all the callers. The host bridge driver is the only code that has > any chance of discovering and/or configuring the correct range. > > So I think it's more correct to leave the existing code here, even though > this code is is likely incorrect. At least then if we trip over an issue > with the bus range being incorrect, it will be clear that the fix should > be in dino.c rather than the PCI core. OK, I would keep this code here, thanks! > > . > -- Thanks! Yijing