On Tue, Jan 29, 2019 at 01:44:09PM -0700, Logan Gunthorpe wrote:
On 2019-01-29 12:44 p.m., Greg Kroah-Hartman wrote:
On Tue, Jan 29, 2019 at 11:24:09AM -0700, Logan Gunthorpe wrote:
On 2019-01-29 10:47 a.m., jglisse@redhat.com 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?
Yes, there are a couple of pci_p2pdma functions that take struct devices directly simply because it's way more convenient for the caller. That's what find_parent_pci_dev() takes care of (it returns false if the device is not a PCI device). Whether that's appropriate here is hard to say seeing we haven't seen any caller code.
Caller code as a reference (i already given that link in other part of thread but just so that people don't have to follow all branches).
https://cgit.freedesktop.org/~glisse/linux/commit/?h=hmm-p2p&id=401a5676...
Cheers, Jérôme