From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yijing Wang Subject: Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci Date: Thu, 12 Mar 2015 19:42:25 +0800 Message-ID: <55017BA1.7020700@huawei.com> References: <1425868467-9667-1-git-send-email-wangyijing@huawei.com> <1425868467-9667-4-git-send-email-wangyijing@huawei.com> <20150311222835.GA1082@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20150311222835.GA1082@google.com> Sender: linux-ia64-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Bjorn Helgaas Cc: Jiang Liu , linux-pci@vger.kernel.org, Yinghai Lu , linux-kernel@vger.kernel.org, Marc Zyngier , linux-arm-kernel@lists.infradead.org, Russell King , x86@kernel.org, Thomas Gleixner , Benjamin Herrenschmidt , Rusty Russell , Tony Luck , linux-ia64@vger.kernel.org, "David S. Miller" , Guan Xuetao , linux-alpha@vger.kernel.org, linux-m68k@lists.linux-m68k.org, Liviu Dudau , Arnd Bergmann , Geert Uytterhoeven >> -static struct resource busn_resource = { >> +struct resource busn_resource = { >> .name = "PCI busn", >> .start = 0, >> .end = 255, >> .flags = IORESOURCE_BUS, >> }; >> +EXPORT_SYMBOL(busn_resource); > > I don't think this is a good idea. We support multiple PCI domains, and > each domain has its own 0-255 bus number range. This busn_resource is > only for domain 0 and probably should be handled in arch code instead of > the PCI core. > > Right now, I think it's possible to call pci_scan_bus_parented() or > pci_scan_bus() several times for buses in different domains, and they would > all share the same busn_resource, which would cause corruption. > > So it's already broken, but I don't want to make it harder to fix by > exporting this stuff. Hi Bjorn, busn_resource may would not be shared by multi domains, We insert bus number resource like: pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here == 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res. So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource. Do I understand correct ? Thanks! Yijing. > >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . > -- Thanks! Yijing From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yijing Wang Date: Thu, 12 Mar 2015 11:42:25 +0000 Subject: Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci Message-Id: <55017BA1.7020700@huawei.com> List-Id: References: <1425868467-9667-1-git-send-email-wangyijing@huawei.com> <1425868467-9667-4-git-send-email-wangyijing@huawei.com> <20150311222835.GA1082@google.com> In-Reply-To: <20150311222835.GA1082@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Bjorn Helgaas Cc: Jiang Liu , linux-pci@vger.kernel.org, Yinghai Lu , linux-kernel@vger.kernel.org, Marc Zyngier , linux-arm-kernel@lists.infradead.org, Russell King , x86@kernel.org, Thomas Gleixner , Benjamin Herrenschmidt , Rusty Russell , Tony Luck , linux-ia64@vger.kernel.org, "David S. Miller" , Guan Xuetao , linux-alpha@vger.kernel.org, linux-m68k@vger.kernel.org, Liviu Dudau , Arnd Bergmann , Geert Uytterhoeven >> -static struct resource busn_resource = { >> +struct resource busn_resource = { >> .name = "PCI busn", >> .start = 0, >> .end = 255, >> .flags = IORESOURCE_BUS, >> }; >> +EXPORT_SYMBOL(busn_resource); > > I don't think this is a good idea. We support multiple PCI domains, and > each domain has its own 0-255 bus number range. This busn_resource is > only for domain 0 and probably should be handled in arch code instead of > the PCI core. > > Right now, I think it's possible to call pci_scan_bus_parented() or > pci_scan_bus() several times for buses in different domains, and they would > all share the same busn_resource, which would cause corruption. > > So it's already broken, but I don't want to make it harder to fix by > exporting this stuff. Hi Bjorn, busn_resource may would not be shared by multi domains, We insert bus number resource like: pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here = 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res. So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource. Do I understand correct ? Thanks! Yijing. > >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . > -- Thanks! Yijing From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from szxga02-in.huawei.com ([119.145.14.65]:37180 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753842AbbCLLnH (ORCPT ); Thu, 12 Mar 2015 07:43:07 -0400 Message-ID: <55017BA1.7020700@huawei.com> Date: Thu, 12 Mar 2015 19:42:25 +0800 From: Yijing Wang 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 Subject: Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci References: <1425868467-9667-1-git-send-email-wangyijing@huawei.com> <1425868467-9667-4-git-send-email-wangyijing@huawei.com> <20150311222835.GA1082@google.com> In-Reply-To: <20150311222835.GA1082@google.com> Content-Type: text/plain; charset="ISO-8859-1" Sender: linux-pci-owner@vger.kernel.org List-ID: >> -static struct resource busn_resource = { >> +struct resource busn_resource = { >> .name = "PCI busn", >> .start = 0, >> .end = 255, >> .flags = IORESOURCE_BUS, >> }; >> +EXPORT_SYMBOL(busn_resource); > > I don't think this is a good idea. We support multiple PCI domains, and > each domain has its own 0-255 bus number range. This busn_resource is > only for domain 0 and probably should be handled in arch code instead of > the PCI core. > > Right now, I think it's possible to call pci_scan_bus_parented() or > pci_scan_bus() several times for buses in different domains, and they would > all share the same busn_resource, which would cause corruption. > > So it's already broken, but I don't want to make it harder to fix by > exporting this stuff. Hi Bjorn, busn_resource may would not be shared by multi domains, We insert bus number resource like: pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here == 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res. So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource. Do I understand correct ? Thanks! Yijing. > >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . > -- Thanks! Yijing From mboxrd@z Thu Jan 1 00:00:00 1970 From: wangyijing@huawei.com (Yijing Wang) Date: Thu, 12 Mar 2015 19:42:25 +0800 Subject: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci In-Reply-To: <20150311222835.GA1082@google.com> References: <1425868467-9667-1-git-send-email-wangyijing@huawei.com> <1425868467-9667-4-git-send-email-wangyijing@huawei.com> <20150311222835.GA1082@google.com> Message-ID: <55017BA1.7020700@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org >> -static struct resource busn_resource = { >> +struct resource busn_resource = { >> .name = "PCI busn", >> .start = 0, >> .end = 255, >> .flags = IORESOURCE_BUS, >> }; >> +EXPORT_SYMBOL(busn_resource); > > I don't think this is a good idea. We support multiple PCI domains, and > each domain has its own 0-255 bus number range. This busn_resource is > only for domain 0 and probably should be handled in arch code instead of > the PCI core. > > Right now, I think it's possible to call pci_scan_bus_parented() or > pci_scan_bus() several times for buses in different domains, and they would > all share the same busn_resource, which would cause corruption. > > So it's already broken, but I don't want to make it harder to fix by > exporting this stuff. Hi Bjorn, busn_resource may would not be shared by multi domains, We insert bus number resource like: pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here == 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res. So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource. Do I understand correct ? Thanks! Yijing. > >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . > -- Thanks! Yijing From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753949AbbCLLnK (ORCPT ); Thu, 12 Mar 2015 07:43:10 -0400 Received: from szxga02-in.huawei.com ([119.145.14.65]:37180 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753842AbbCLLnH (ORCPT ); Thu, 12 Mar 2015 07:43:07 -0400 Message-ID: <55017BA1.7020700@huawei.com> Date: Thu, 12 Mar 2015 19:42:25 +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 Subject: Re: [PATCH v6 03/30] PCI: Export busn_resource to drivers/pci References: <1425868467-9667-1-git-send-email-wangyijing@huawei.com> <1425868467-9667-4-git-send-email-wangyijing@huawei.com> <20150311222835.GA1082@google.com> In-Reply-To: <20150311222835.GA1082@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 >> -static struct resource busn_resource = { >> +struct resource busn_resource = { >> .name = "PCI busn", >> .start = 0, >> .end = 255, >> .flags = IORESOURCE_BUS, >> }; >> +EXPORT_SYMBOL(busn_resource); > > I don't think this is a good idea. We support multiple PCI domains, and > each domain has its own 0-255 bus number range. This busn_resource is > only for domain 0 and probably should be handled in arch code instead of > the PCI core. > > Right now, I think it's possible to call pci_scan_bus_parented() or > pci_scan_bus() several times for buses in different domains, and they would > all share the same busn_resource, which would cause corruption. > > So it's already broken, but I don't want to make it harder to fix by > exporting this stuff. Hi Bjorn, busn_resource may would not be shared by multi domains, We insert bus number resource like: pci_add_resource(&resources, &busn_resource); pci_bus_insert_busn_res(root_bus, start, bus_max); //start is the root bus number provided by arch pci host driver, bus max here == 255 get_pci_domain_busn_res(domain) //for root bus //try to get a domain specific pci_domain_busn_res, if not exist, create it. request_resource_conflict(domain_specific_busn_res, res) //request busn res(start, bus_max) from the pci_domain_busn_res. So every domain has its own pci_domain_busn_res , different domain would not share the same bus number resource. Do I understand correct ? Thanks! Yijing. > >> >> /* Ugh. Need to stop exporting this to modules. */ >> LIST_HEAD(pci_root_buses); >> -- >> 1.7.1 >> > > . > -- Thanks! Yijing