From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com ([134.134.136.24]:65293 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758059Ab3ENVjB (ORCPT ); Tue, 14 May 2013 17:39:01 -0400 Message-ID: <5192AEF4.1070905@intel.com> Date: Tue, 14 May 2013 14:39:00 -0700 From: Alexander Duyck MIME-Version: 1.0 To: Yinghai Lu CC: Bjorn Helgaas , Gu Zheng , "linux-pci@vger.kernel.org" , Linux Kernel Mailing List , NetDev 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> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-pci-owner@vger.kernel.org List-ID: 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. Thanks, Alex