| Message ID | 1502936730-7368-1-git-send-email-dingtianhong@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
From: Ding Tianhong <dingtianhong@huawei.com> Date: Thu, 17 Aug 2017 10:25:30 +0800 > The pci_find_pcie_root_port() would return NULL if the given > dev is already a Root Port, it looks like unfriendly to the > PCIe Root Port device, Thierry and Bjorn suggest to let this > function return the given dev under this circumstances. > > Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") > Suggested-by: Thierry Reding <thierry.reding@gmail.com> > Suggested-by: Bjorn Helgaas <helgaas@kernel.org> > Signed-off-by: Thierry Reding <thierry.reding@gmail.com> > Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> Bjorn, please review and ACK so Linus doesn't rip my head off again :-) Thanks.
On Thu, Aug 17, 2017 at 10:25:30AM +0800, Ding Tianhong wrote: > The pci_find_pcie_root_port() would return NULL if the given > dev is already a Root Port, it looks like unfriendly to the > PCIe Root Port device, Thierry and Bjorn suggest to let this > function return the given dev under this circumstances. > > Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") > Suggested-by: Thierry Reding <thierry.reding@gmail.com> > Suggested-by: Bjorn Helgaas <helgaas@kernel.org> > Signed-off-by: Thierry Reding <thierry.reding@gmail.com> > Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> > --- > drivers/pci/pci.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 7e2022f..352bb53 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -514,7 +514,7 @@ struct resource *pci_find_resource(struct pci_dev *dev, struct resource *res) > */ > struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) > { > - struct pci_dev *bridge, *highest_pcie_bridge = NULL; > + struct pci_dev *bridge, *highest_pcie_bridge = dev; > > bridge = pci_upstream_bridge(dev); > while (bridge && pci_is_pcie(bridge)) { I think this should actually be this change on top of a revert of commit 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device"). After the above change, the previous fix will have a redundant check because highest_pcie_bridge will never be NULL. Let me send out that version to clarify what I mean. Thierry
On 2017/8/17 18:51, Thierry Reding wrote: > On Thu, Aug 17, 2017 at 10:25:30AM +0800, Ding Tianhong wrote: >> The pci_find_pcie_root_port() would return NULL if the given >> dev is already a Root Port, it looks like unfriendly to the >> PCIe Root Port device, Thierry and Bjorn suggest to let this >> function return the given dev under this circumstances. >> >> Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") >> Suggested-by: Thierry Reding <thierry.reding@gmail.com> >> Suggested-by: Bjorn Helgaas <helgaas@kernel.org> >> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> >> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >> --- >> drivers/pci/pci.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 7e2022f..352bb53 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -514,7 +514,7 @@ struct resource *pci_find_resource(struct pci_dev *dev, struct resource *res) >> */ >> struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) >> { >> - struct pci_dev *bridge, *highest_pcie_bridge = NULL; >> + struct pci_dev *bridge, *highest_pcie_bridge = dev; >> >> bridge = pci_upstream_bridge(dev); >> while (bridge && pci_is_pcie(bridge)) { > > I think this should actually be this change on top of a revert of commit > 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI > device"). After the above change, the previous fix will have a redundant > check because highest_pcie_bridge will never be NULL. > > Let me send out that version to clarify what I mean. > Hi Thierry: The patch ("PCI: fix oops when try to find Root Port for a PCI device") has been merge to the linus mainline tree before you found this deficiencies.... Regards Tianhong > Thierry >
On Thu, Aug 17, 2017 at 08:40:16PM +0800, Ding Tianhong wrote: > > > On 2017/8/17 18:51, Thierry Reding wrote: > > On Thu, Aug 17, 2017 at 10:25:30AM +0800, Ding Tianhong wrote: > >> The pci_find_pcie_root_port() would return NULL if the given > >> dev is already a Root Port, it looks like unfriendly to the > >> PCIe Root Port device, Thierry and Bjorn suggest to let this > >> function return the given dev under this circumstances. > >> > >> Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") > >> Suggested-by: Thierry Reding <thierry.reding@gmail.com> > >> Suggested-by: Bjorn Helgaas <helgaas@kernel.org> > >> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> > >> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> > >> --- > >> drivers/pci/pci.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > >> index 7e2022f..352bb53 100644 > >> --- a/drivers/pci/pci.c > >> +++ b/drivers/pci/pci.c > >> @@ -514,7 +514,7 @@ struct resource *pci_find_resource(struct pci_dev *dev, struct resource *res) > >> */ > >> struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) > >> { > >> - struct pci_dev *bridge, *highest_pcie_bridge = NULL; > >> + struct pci_dev *bridge, *highest_pcie_bridge = dev; > >> > >> bridge = pci_upstream_bridge(dev); > >> while (bridge && pci_is_pcie(bridge)) { > > > > I think this should actually be this change on top of a revert of commit > > 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI > > device"). After the above change, the previous fix will have a redundant > > check because highest_pcie_bridge will never be NULL. > > > > Let me send out that version to clarify what I mean. > > > > Hi Thierry: > > The patch ("PCI: fix oops when try to find Root Port for a PCI device") > has been merge to the linus mainline tree before you found this deficiencies.... I understand that. I'm just saying that there's no point keeping that change around because it no longer makes sense after we initialize the highest_pcie_bridge variable to dev. Thierry
On 2017/8/17 21:30, Thierry Reding wrote: > On Thu, Aug 17, 2017 at 08:40:16PM +0800, Ding Tianhong wrote: >> >> >> On 2017/8/17 18:51, Thierry Reding wrote: >>> On Thu, Aug 17, 2017 at 10:25:30AM +0800, Ding Tianhong wrote: >>>> The pci_find_pcie_root_port() would return NULL if the given >>>> dev is already a Root Port, it looks like unfriendly to the >>>> PCIe Root Port device, Thierry and Bjorn suggest to let this >>>> function return the given dev under this circumstances. >>>> >>>> Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") >>>> Suggested-by: Thierry Reding <thierry.reding@gmail.com> >>>> Suggested-by: Bjorn Helgaas <helgaas@kernel.org> >>>> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> >>>> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> >>>> --- >>>> drivers/pci/pci.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >>>> index 7e2022f..352bb53 100644 >>>> --- a/drivers/pci/pci.c >>>> +++ b/drivers/pci/pci.c >>>> @@ -514,7 +514,7 @@ struct resource *pci_find_resource(struct pci_dev *dev, struct resource *res) >>>> */ >>>> struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) >>>> { >>>> - struct pci_dev *bridge, *highest_pcie_bridge = NULL; >>>> + struct pci_dev *bridge, *highest_pcie_bridge = dev; >>>> >>>> bridge = pci_upstream_bridge(dev); >>>> while (bridge && pci_is_pcie(bridge)) { >>> >>> I think this should actually be this change on top of a revert of commit >>> 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI >>> device"). After the above change, the previous fix will have a redundant >>> check because highest_pcie_bridge will never be NULL. >>> >>> Let me send out that version to clarify what I mean. >>> >> >> Hi Thierry: >> >> The patch ("PCI: fix oops when try to find Root Port for a PCI device") >> has been merge to the linus mainline tree before you found this deficiencies.... > > I understand that. I'm just saying that there's no point keeping that > change around because it no longer makes sense after we initialize the > highest_pcie_bridge variable to dev. > Ok, NO problem.:) > Thierry >
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 7e2022f..352bb53 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -514,7 +514,7 @@ struct resource *pci_find_resource(struct pci_dev *dev, struct resource *res) */ struct pci_dev *pci_find_pcie_root_port(struct pci_dev *dev) { - struct pci_dev *bridge, *highest_pcie_bridge = NULL; + struct pci_dev *bridge, *highest_pcie_bridge = dev; bridge = pci_upstream_bridge(dev); while (bridge && pci_is_pcie(bridge)) {
The pci_find_pcie_root_port() would return NULL if the given dev is already a Root Port, it looks like unfriendly to the PCIe Root Port device, Thierry and Bjorn suggest to let this function return the given dev under this circumstances. Fixes: 0e405232871d6 ("PCI: fix oops when try to find Root Port for a PCI device") Suggested-by: Thierry Reding <thierry.reding@gmail.com> Suggested-by: Bjorn Helgaas <helgaas@kernel.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com> Signed-off-by: Ding Tianhong <dingtianhong@huawei.com> --- drivers/pci/pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)