Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754082Ab3EUVcD (ORCPT ); Tue, 21 May 2013 17:32:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64446 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753223Ab3EUVb7 (ORCPT ); Tue, 21 May 2013 17:31:59 -0400 Message-ID: <519BE7C4.3050306@redhat.com> Date: Tue, 21 May 2013 17:31:48 -0400 From: Don Dutile User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.11) Gecko/20121116 Thunderbird/10.0.11 MIME-Version: 1.0 To: Alexander Duyck CC: Yinghai Lu , Bjorn Helgaas , Gu Zheng , "linux-pci@vger.kernel.org" , Linux Kernel Mailing List , NetDev , "Michael S. Tsirkin" Subject: Re: [PATCH 6/7] PCI: Make sure VF's driver get attached after PF's References: <1368498506-25857-1-git-send-email-yinghai@kernel.org> <1368498506-25857-7-git-send-email-yinghai@kernel.org> <51925FB0.4080504@intel.com> <5192946F.1050700@intel.com> <5192AEF4.1070905@intel.com> <519BE778.9040800@redhat.com> In-Reply-To: <519BE778.9040800@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; 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: 3193 Lines: 70 On 05/21/2013 05:30 PM, Don Dutile wrote: > On 05/14/2013 05:39 PM, Alexander Duyck wrote: >> On 05/14/2013 12:59 PM, Yinghai Lu wrote: >>> On Tue, May 14, 2013 at 12:45 PM, Alexander Duyck >>> wrote: >>>> On 05/14/2013 11:44 AM, Yinghai Lu wrote: >>>>> On Tue, May 14, 2013 at 9:00 AM, Alexander Duyck >>>>> wrote: >>>>>> I'm sorry, but what is the point of this patch? With device assignment >>>>>> it is always possible to have VFs loaded and the PF driver unloaded >>>>>> since you cannot remove the VFs if they are assigned to a VM. >>>>> unload PF driver will not call pci_disable_sriov? >>>> You cannot call pci_disable_sriov because you will panic all of the >>>> guests that have devices assigned. >>> ixgbe_remove did call pci_disable_sriov... >>> >>> for guest panic, that is another problem. >>> just like you pci passthrough with real pci device and hotremove the >>> card in host. >>> >>> ... >> >> I suggest you take another look. In ixgbe_disable_sriov, which is the >> function that is called we do a check for assigned VFs. If they are >> assigned then we do not call pci_disable_sriov. >> >>> >>>> So how does your patch actually fix this problem? It seems like it is >>>> just avoiding it. >>> yes, until the first one is done. >> >> Avoiding the issue doesn't fix the underlying problem and instead you >> are likely just introducing more bugs as a result. >> >>>> From what I can tell your problem is originating in pci_call_probe. I >>>> believe it is calling work_on_cpu and that doesn't seem correct since >>>> the work should be taking place on a CPU already local to the PF. You >>>> might want to look there to see why you are trying to schedule work on a >>>> CPU which should be perfectly fine for you to already be doing your work on. >>> it always try to go with local cpu with same pxm. >> >> The problem is we really shouldn't be calling work_for_cpu in this case >> since we are already on the correct CPU. What probably should be >> happening is that pci_call_probe should be doing a check to see if the >> current CPU is already contained within the device node map and if so >> just call local_pci_probe directly. That way you can avoid deadlocking >> the system by trying to flush the CPU queue of the CPU you are currently on. >> > That's the patch that Michael Tsirkin posted for a fix, > but it was noted that if you have the case where the _same_ driver is used for vf & pf, > other deadlocks may occur. > It would work in the case of ixgbe/ixgbevf, but not for something like > the Mellanox pf/vf driver (which is the same). > apologies; here's the thread the discussed the issue: https://patchwork.kernel.org/patch/2458681/ >> >> Alex >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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/