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Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for a PCI device

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Thierry Reding <thierry.reding@gmail.com> writes:
...
>
> In case of Tegra, dev actually points to the root port. Now if I read
> the above code correctly, highest_pcie_bridge will still be NULL in that
> case, which in turn will return NULL from pci_find_pcie_root_port(). But
> shouldn't it really return dev?
>
> The patch that I used to fix the issue is this:
>
> --->8---
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 2c712dcfd37d..dd56c1c05614 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -514,7 +514,7 @@ EXPORT_SYMBOL(pci_find_resource);
>   */
>  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)) {
> --->8---
>
> That works correctly if this function ends up being called on the PCIe
> root port, though perhaps that's not what this function is supposed to
> do. It's somewhat unclear from the kerneldoc what the function should
> be doing when called on a root port device itself.

That also works for me on powerpc (oops reported up thread).

cheers

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[PATCH net RESEND] PCI: fix oops when try to find Root Port for a PCI device Ding Tianhong <dingtianhong@huawei.com> - 2017-08-15 17:30 +0200
  Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for  a PCI device Bjorn Helgaas <helgaas@kernel.org> - 2017-08-15 19:10 +0200
    Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port  for a PCI device David Miller <davem@davemloft.net> - 2017-08-16 02:30 +0200
    Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for  a PCI device Thierry Reding <thierry.reding@gmail.com> - 2017-08-16 21:40 +0200
      Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for  a PCI device Bjorn Helgaas <helgaas@kernel.org> - 2017-08-16 22:10 +0200
        Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port  for a PCI device David Miller <davem@davemloft.net> - 2017-08-16 23:10 +0200
          Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for a  PCI device Ding Tianhong <dingtianhong@huawei.com> - 2017-08-17 03:20 +0200
      Re: [PATCH net RESEND] PCI: fix oops when try to find Root Port for a PCI device Michael Ellerman <mpe@ellerman.id.au> - 2017-08-17 07:20 +0200

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