From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755269Ab2IHPac (ORCPT ); Sat, 8 Sep 2012 11:30:32 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:61086 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755000Ab2IHPa3 (ORCPT ); Sat, 8 Sep 2012 11:30:29 -0400 MIME-Version: 1.0 In-Reply-To: <20120908134220.GA24831@localhost> References: <20120731235705.GW2422@linux.vnet.ibm.com> <1343779778.27983.73.camel@gandalf.stny.rr.com> <20120801001811.GX2422@linux.vnet.ibm.com> <20120801004319.GA7043@localhost> <20120822025008.GA8066@localhost> <20120822154908.2e6ef3c0@feng-i7> <20120823154503.15a45b14@feng-i7> <20120908134220.GA24831@localhost> Date: Sat, 8 Sep 2012 08:30:26 -0700 X-Google-Sender-Auth: r-vpbSkdWDDG3vhzxUfsgX6ibkA Message-ID: Subject: Re: [PATCH 1/2] PCI: Use local parameter pci_device_id for pci_get_subsys/class() From: Yinghai Lu To: Fengguang Wu Cc: Greg Kroah-Hartman , "Paul E. McKenney" , Steven Rostedt , Avi Kivity , Steven Rostedt , LKML , "kvm@vger.kernel.org" , Kenji Kaneshige , linux-pci@vger.kernel.org, Feng Tang , Bjorn Helgaas Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Sep 8, 2012 at 6:42 AM, Fengguang Wu wrote: > On Fri, Sep 07, 2012 at 06:32:48PM -0700, Yinghai Lu wrote: > >> > with this one in pci/next pci config in /sys are not created. >> > >> > 10:~ # lspci -tv >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:03.0/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:03.0 >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:02.0/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:02.0 >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:01.3/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:01.3 >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:01.1/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:01.1 >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:01.0/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:01.0 >> > pcilib: Cannot open /sys/bus/pci/devices/0000:00:00.0/config >> > lspci: Unable to read the standard configuration space header of >> > device 0000:00:00.0 >> > -[0000:00]- >> > >> > bisected to this commit >> > >> > ccee7d23102f5e5765ec24779c5b77472af8f79e is the first bad commit >> > commit ccee7d23102f5e5765ec24779c5b77472af8f79e >> > Author: Feng Tang >> > Date: Thu Aug 23 15:45:03 2012 +0800 >> > >> > PCI: Use pci_device_id on stack for pci_get_subsys/class() to avoid kmalloc >> > >> > This fixes a kernel warning https://lkml.org/lkml/2012/7/31/682 >> > >> > pci_get_subsys() may get called in late system reboot stage, using >> > a sleepable kmalloc() sounds fragile and will cause a kernel warning >> > with my recent commmit 55c844a "x86/reboot: Fix a warning message >> > triggered by stop_other_cpus()" which disable local interrupt in >> > late system shutdown/reboot phase. Using a local parameter instead >> > will fix it and make it eligible for calling forom atomic context. >> > >> > Do the same change for the pci_get_class() as suggested by Bjorn Helgaas >> > >> > [bhelgaas: changelog] >> > Bisected-by: Fengguang Wu >> > Signed-off-by: Feng Tang >> > Signed-off-by: Bjorn Helgaas >> > Reviewed-by: Fengguang Wu >> > >> > :040000 040000 dee62a035816b73abc68e40de8f21c7349efc4cb >> > 70b2a6258bffa1ab963bd650d8f5d02da774fbce M drivers >> > >> > so the stack get overrun ? >> > >> > Bjorn, I think it is this one that cause lspci broken that I mentioned >> > during meeting at San Diego. > > This makes lspci work again on my side. The caveat is, kzalloc() will > zero out all data while the new local variable leaves some data > uninitialized. > > diff --git a/drivers/pci/search.c b/drivers/pci/search.c > index 78a08b1..9148b6e 100644 > --- a/drivers/pci/search.c > +++ b/drivers/pci/search.c > @@ -245,7 +245,12 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, > unsigned int ss_vendor, unsigned int ss_device, > struct pci_dev *from) > { > - struct pci_device_id id; > + struct pci_device_id id = { > + .vendor = vendor, > + .device = device, > + .subvendor = ss_vendor, > + .subdevice = ss_device, > + }; > > /* > * pci_find_subsys() can be called on the ide_setup() path, > @@ -256,11 +261,6 @@ struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, > if (unlikely(no_pci_devices())) > return NULL; > > - id.vendor = vendor; > - id.device = device; > - id.subvendor = ss_vendor; > - id.subdevice = ss_device; > - yes, here forget to clear .class and .class_mask > return pci_get_dev_by_id(&id, from); > } > > @@ -300,11 +300,14 @@ pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from) > */ > struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) > { > - struct pci_device_id id; > - > - id.vendor = id.device = id.subvendor = id.subdevice = PCI_ANY_ID; > - id.class_mask = PCI_ANY_ID; > - id.class = class; > + struct pci_device_id id = { > + .vendor = PCI_ANY_ID, > + .device = PCI_ANY_ID, > + .subvendor = PCI_ANY_ID, > + .subdevice = PCI_ANY_ID, > + .class_mask = PCI_ANY_ID, > + .class = class, > + }; > > return pci_get_dev_by_id(&id, from); > }