On Thu, Dec 03, 2020 at 06:45:00PM +0000, Kelley, Sean V wrote: > Just confirming that when switched from dev->bus->self to > pci_upstream_bridge() we’re okay with the NULL case: > > > On Nov 20, 2020, at 4:10 PM, Sean V Kelley <sean.v.kel...@intel.com> wrote: > > > > Use pci_upstream_bridge() in place of dev->bus->self. No functional change > > intended. > > > > [bhelgaas: split to separate patch] > > Link: > > https://lore.kernel.org/r/20201002184735.1229220-6-seanvk....@oregontracks.org > > Signed-off-by: Sean V Kelley <sean.v.kel...@intel.com> > > Signed-off-by: Bjorn Helgaas <bhelg...@google.com> > > Acked-by: Jonathan Cameron <jonathan.came...@huawei.com> > > Reviewed-by: Kuppuswamy Sathyanarayanan > > <sathyanarayanan.kuppusw...@linux.intel.com> > > --- > > drivers/pci/pcie/err.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c > > index db149c6ce4fb..05f61da5ed9d 100644 > > --- a/drivers/pci/pcie/err.c > > +++ b/drivers/pci/pcie/err.c > > @@ -159,7 +159,7 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > > */ > > if (!(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT || > > pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)) > > - dev = dev->bus->self; > > + dev = pci_upstream_bridge(dev); > > The only case where pci_upstream_bridge(dev) could be NULL is if > dev->bus is the root bus and we are being selective based on the > type.
Yes, pci_upstream_bridge(dev) returns NULL if dev is on a root bus. I think bus->self is NULL for root buses anyway, so I think this patch is OK at least at this point in the series. > Even later in this series when we actually add in RC_EC/RC_END we > maintain the conditional checks: > > https://lore.kernel.org/linux-pci/20201121001036.8560-11-sean.v.kel...@intel.com/ > > pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > > @@ -174,10 +180,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev, > > > /* > * Error recovery runs on all subordinates of the bridge. If the > - * bridge detected the error, it is cleared at the end. > + * bridge detected the error, it is cleared at the end. For RCiEPs > + * we should reset just the RCiEP itself. > > */ > if (type == PCI_EXP_TYPE_ROOT_PORT || > - type == PCI_EXP_TYPE_DOWNSTREAM) > + type == PCI_EXP_TYPE_DOWNSTREAM || > + type == PCI_EXP_TYPE_RC_EC || > + type == PCI_EXP_TYPE_RC_END) > bridge = dev; > else > bridge = pci_upstream_bridge(dev); > > I believe we are okay here. Well, I think we're at least no worse than today. Today we keep "bridge == dev" for Root Ports and Downstream Ports, and use "bridge = dev->bus->self" for everything else. After this series we keep "bridge == dev" for RCEC and RCiEPs in addition. I'm not sure about PCI_EXP_TYPE_PCI_BRIDGE, which is a PCIe-to-PCI bridge. According to the ancient "PCI Express to PCI/PCI-X Bridge Specification" r1.0 of July 14, 2003, sec 5.23, these bridges can have an AER Capability (with different format that I don't see mentioned elsewhere). But this AER Capability doesn't have the Root registers, so I assume it would have to be below a Root Port in order to actually signal the errors, which would mean it could not be on a root bus. So I don't really *love* the fact that we use pci_upstream_bridge() and rely on these assumptions that the result will not be NULL, but I guess it's OK for now. > > bus = dev->subordinate; > > > > pci_dbg(dev, "broadcast error_detected message\n"); > > -- > > 2.29.2 > > > > >
