From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97EF0C433FF for ; Tue, 13 Aug 2019 12:59:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 733C3206C2 for ; Tue, 13 Aug 2019 12:59:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728682AbfHMM7c (ORCPT ); Tue, 13 Aug 2019 08:59:32 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:38052 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728289AbfHMM7c (ORCPT ); Tue, 13 Aug 2019 08:59:32 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id A4520AA611A670BAC016; Tue, 13 Aug 2019 20:43:46 +0800 (CST) Received: from [127.0.0.1] (10.133.213.239) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Tue, 13 Aug 2019 20:43:41 +0800 Subject: Re: [PATCH] PCI: hv: Fix build error without CONFIG_SYSFS To: Lorenzo Pieralisi References: <20190531150923.12376-1-yuehaibing@huawei.com> <7d8ca05e-7519-45d8-e694-d31e221696d5@huawei.com> <20190813101845.GB14977@e121166-lin.cambridge.arm.com> CC: Michael Kelley , "bhelgaas@google.com" , Stephen Hemminger , "sashal@kernel.org" , Dexuan Cui , "linux-hyperv@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" From: Yuehaibing Message-ID: <7c651711-7bf6-f2ca-cd4e-edcc0a7438e2@huawei.com> Date: Tue, 13 Aug 2019 20:43:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20190813101845.GB14977@e121166-lin.cambridge.arm.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.133.213.239] X-CFilter-Loop: Reflected Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On 2019/8/13 18:18, Lorenzo Pieralisi wrote: > On Sat, Jun 15, 2019 at 02:48:24PM +0800, Yuehaibing wrote: >> +cc Lorenzo Pieralisi > > Can we drop this patch and merge: > > https://patchwork.ozlabs.org/patch/1131444/ > > instead ? Ok, it looks good to me, thanks! > > Thanks, > Lorenzo > >> >> On 2019/6/15 14:18, Yuehaibing wrote: >>> >>> On 2019/6/2 6:59, Michael Kelley wrote: >>>> From: YueHaibing Sent: Friday, May 31, 2019 8:09 AM >>>>> >>>>> while building without CONFIG_SYSFS, fails as below: >>>>> >>>>> drivers/pci/controller/pci-hyperv.o: In function 'hv_pci_assign_slots': >>>>> pci-hyperv.c:(.text+0x40a): undefined reference to 'pci_create_slot' >>>>> drivers/pci/controller/pci-hyperv.o: In function 'pci_devices_present_work': >>>>> pci-hyperv.c:(.text+0xc02): undefined reference to 'pci_destroy_slot' >>>>> drivers/pci/controller/pci-hyperv.o: In function 'hv_pci_remove': >>>>> pci-hyperv.c:(.text+0xe50): undefined reference to 'pci_destroy_slot' >>>>> drivers/pci/controller/pci-hyperv.o: In function 'hv_eject_device_work': >>>>> pci-hyperv.c:(.text+0x11f9): undefined reference to 'pci_destroy_slot' >>>>> >>>>> Select SYSFS while PCI_HYPERV is set to fix this. >>>>> >>>> >>>> I'm wondering if is the right way to fix the problem. Conceptually >>>> is it possible to setup & operate virtual PCI devices like >>>> pci-hyperv.c does, even if sysfs is not present? Or is it right to >>>> always required sysfs? >>>> >>>> The function pci_dev_assign_slot() in slot.c has a null implementation >>>> in include/linux/pci.h when CONFIG_SYSFS is not defined, which >>>> seems to be trying to solve the same problem for that function. And >>>> if CONFIG_HOTPLUG_PCI is defined but CONFIG_SYSFS is not, >>>> pci_hp_create_module_link() and pci_hp_remove_module_link() >>>> look like they would have the same problem. Maybe there should >>>> be degenerate implementations of pci_create_slot() and >>>> pci_destroy_slot() for cases when CONFIG_SYSFS is not defined? >>>> >>>> But I'll admit I don't know the full story behind how PCI slots >>>> are represented and used, so maybe I'm off base. I just noticed >>>> the inconsistency in how other functions in slot.c are handled. >>>> >>>> Thoughts? >>> >>> 268a03a42d33 ("PCI: drivers/pci/slot.c should depend on CONFIG_SYSFS") >>> >>> make slot.o depends CONFIG_SYSFS >>> >>> commit 268a03a42d3377d5fb41e6e7cbdec4e0b65cab2e >>> Author: Alex Chiang >>> Date: Wed Jun 17 19:03:57 2009 -0600 >>> >>> PCI: drivers/pci/slot.c should depend on CONFIG_SYSFS >>> >>> There is no way to interact with a physical PCI slot without >>> sysfs, so encode the dependency and prevent this build error: >>> >>> drivers/pci/slot.c: In function 'pci_hp_create_module_link': >>> drivers/pci/slot.c:327: error: 'module_kset' undeclared >>> >>> This patch _should_ make pci-sysfs.o depend on CONFIG_SYSFS too, >>> but we cannot (yet) because the PCI core merrily assumes the >>> existence of sysfs: >>> >>> drivers/built-in.o: In function `pci_bus_add_device': >>> drivers/pci/bus.c:89: undefined reference to `pci_create_sysfs_dev_files' >>> drivers/built-in.o: In function `pci_stop_dev': >>> drivers/pci/remove.c:24: undefined reference to `pci_remove_sysfs_dev_files' >>> >>> So do the minimal bit for now and figure out how to untangle it >>> later. >>> >>> If No CONFIG_SYSFS, slot.o is not build >>> >>>> >>>> Michael >>>> >>>> >>> >>> >>> . >>> >> > > . >