On Tue, Jan 29, 2019 at 11:24:09AM -0700, Logan Gunthorpe wrote: > > > On 2019-01-29 10:47 a.m., jglisse@xxxxxxxxxx wrote: > > +bool pci_test_p2p(struct device *devA, struct device *devB) > > +{ > > + struct pci_dev *pciA, *pciB; > > + bool ret; > > + int tmp; > > + > > + /* > > + * For now we only support PCIE peer to peer but other inter-connect > > + * can be added. > > + */ > > + pciA = find_parent_pci_dev(devA); > > + pciB = find_parent_pci_dev(devB); > > + if (pciA == NULL || pciB == NULL) { > > + ret = false; > > + goto out; > > + } > > + > > + tmp = upstream_bridge_distance(pciA, pciB, NULL); > > + ret = tmp < 0 ? false : true; > > + > > +out: > > + pci_dev_put(pciB); > > + pci_dev_put(pciA); > > + return false; > > +} > > +EXPORT_SYMBOL_GPL(pci_test_p2p); > > This function only ever returns false.... I guess it was nevr actually tested :( I feel really worried about passing random 'struct device' pointers into the PCI layer. Are we _sure_ it can handle this properly? thanks, greg k-h