From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com ([134.134.136.20]:54164 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757040Ab2IUIxl (ORCPT ); Fri, 21 Sep 2012 04:53:41 -0400 Message-ID: <1348217616.23395.55.camel@yhuang-dev> Subject: Re: [PATCH v5 1/5] PCI/AER: Fix pci_ops return NULL in pci_read/write_aer From: Huang Ying To: Yijing Wang Cc: Bjorn Helgaas , Chen Gong , jiang.liu@huawei.com, Hanjun Guo , linux-pci@vger.kernel.org Date: Fri, 21 Sep 2012 16:53:36 +0800 In-Reply-To: <1348216993-6948-2-git-send-email-wangyijing@huawei.com> References: <1348216993-6948-1-git-send-email-wangyijing@huawei.com> <1348216993-6948-2-git-send-email-wangyijing@huawei.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: On Fri, 2012-09-21 at 16:43 +0800, Yijing Wang wrote: > When we injected aer errors to the pcie device by aer_inject module, pci_ops of the pci > bus the device on will be assigned to pci_ops_aer.So if the target pci device > is a bridge, once we hot-remove and hot-add the bridge, the newly created child bus's pci_ops > will be assigned to pci_ops_aer too.Now every access to the child bus's device will cause the > system panic, because it will get a NULL pci_ops in pci_read_aer/pci_write_aer. > > Signed-off-by: Yijing Wang > Signed-off-by: Jiang Liu > Reviewed-by: Sven Dietrich Reviewed-by: Huang Ying > --- > drivers/pci/pcie/aer/aer_inject.c | 26 +++++++++++++++++++++++++- > 1 files changed, 25 insertions(+), 1 deletions(-) > > diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c > index 4e24cb8..fdab3bb 100644 > --- a/drivers/pci/pcie/aer/aer_inject.c > +++ b/drivers/pci/pcie/aer/aer_inject.c > @@ -109,6 +109,26 @@ static struct aer_error *__find_aer_error_by_dev(struct pci_dev *dev) > return __find_aer_error((u16)domain, dev->bus->number, dev->devfn); > } > > +/* find pci_ops of the nearest parent bus */ > +static struct pci_ops *__find_pci_bus_ops_parent(struct pci_bus *bus) > +{ > + struct pci_bus_ops *bus_ops; > + struct pci_bus *pbus = bus->parent; > + > + if (!pbus) > + return NULL; > + > + while (pbus) { > + list_for_each_entry(bus_ops, &pci_bus_ops_list, list) > + if (bus_ops->bus == pbus) > + return bus_ops->ops; > + > + pbus = pbus->parent; > + } > + > + return NULL; > +} > + > /* inject_lock must be held before calling */ > static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus) > { > @@ -118,7 +138,9 @@ static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus) > if (bus_ops->bus == bus) > return bus_ops->ops; > } > - return NULL; > + > + /* can't find bus_ops, fall back to get bus_ops of parent bus */ > + return __find_pci_bus_ops_parent(bus); > } > > static struct pci_bus_ops *pci_bus_ops_pop(void) > @@ -208,6 +230,7 @@ static int pci_read_aer(struct pci_bus *bus, unsigned int devfn, int where, > } > out: > ops = __find_pci_bus_ops(bus); > + BUG_ON(!ops); > spin_unlock_irqrestore(&inject_lock, flags); > return ops->read(bus, devfn, where, size, val); > } > @@ -243,6 +266,7 @@ int pci_write_aer(struct pci_bus *bus, unsigned int devfn, int where, int size, > } > out: > ops = __find_pci_bus_ops(bus); > + BUG_ON(!ops); > spin_unlock_irqrestore(&inject_lock, flags); > return ops->write(bus, devfn, where, size, val); > }