Commit c8b1a83605e4 changed the function, making it impossible for callers to be able to tell whether a non-negative return value means "physical function address found and parsed correctly" or "couldn't find corresponding physical function". The important difference between the two being that, in the latter case, the returned pointer is NULL and should never, ever be dereferenced. In order to cope with these changes, the callers have to be updated. Some documentation has also been added to the function, so that callers know how to handle the return value and returned data properly. --- src/node_device/node_device_linux_sysfs.c | 10 ++++++++-- src/util/virpci.c | 18 ++++++++++++++++-- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/src/node_device/node_device_linux_sysfs.c b/src/node_device/node_device_linux_sysfs.c index 24a6a2e..b337d2d 100644 --- a/src/node_device/node_device_linux_sysfs.c +++ b/src/node_device/node_device_linux_sysfs.c @@ -154,19 +154,25 @@ nodeDeviceSysfsGetPCISRIOVCaps(const char *sysfsPath, data->pci_dev.flags &= ~VIR_NODE_DEV_CAP_FLAG_PCI_VIRTUAL_FUNCTION; data->pci_dev.flags &= ~VIR_NODE_DEV_CAP_FLAG_PCI_PHYSICAL_FUNCTION; - if (!virPCIGetPhysicalFunction(sysfsPath, &data->pci_dev.physical_function)) + ret = virPCIGetPhysicalFunction(sysfsPath, + &data->pci_dev.physical_function); + if (ret < 0) + goto out; + + if (data->pci_dev.physical_function) data->pci_dev.flags |= VIR_NODE_DEV_CAP_FLAG_PCI_PHYSICAL_FUNCTION; ret = virPCIGetVirtualFunctions(sysfsPath, &data->pci_dev.virtual_functions, &data->pci_dev.num_virtual_functions, &data->pci_dev.max_virtual_functions); if (ret < 0) - return ret; + goto out; if (data->pci_dev.num_virtual_functions > 0 || data->pci_dev.max_virtual_functions > 0) data->pci_dev.flags |= VIR_NODE_DEV_CAP_FLAG_PCI_VIRTUAL_FUNCTION; + out: return ret; } diff --git a/src/util/virpci.c b/src/util/virpci.c index 3d18bb3..e8dc987 100644 --- a/src/util/virpci.c +++ b/src/util/virpci.c @@ -2478,8 +2478,19 @@ virPCIGetDeviceAddressFromSysfsLink(const char *device_link) return bdf; } -/* - * Returns Physical function given a virtual function +/** + * virPCIGetPhysicalFunction: + * @vf_sysfs_path: sysfs path for the virtual function + * @pf: where to store the physical function's address + * + * Given @vf_sysfs_path, this function will store the pointer + * to a newly-allocated virPCIDeviceAddress in @pf. + * + * @pf might be NULL if @vf_sysfs_path does not point to a + * virtual function. If it's not NULL, then it should be + * freed by the caller when no longer needed. + * + * Returns: >=0 on success, <0 on failure */ int virPCIGetPhysicalFunction(const char *vf_sysfs_path, @@ -2719,6 +2730,9 @@ virPCIGetVirtualFunctionInfo(const char *vf_sysfs_device_path, if (virPCIGetPhysicalFunction(vf_sysfs_device_path, &pf_config_address) < 0) return ret; + if (!pf_config_address) + return ret; + if (virPCIDeviceAddressGetSysfsFile(pf_config_address, &pf_sysfs_device_path) < 0) { -- 2.5.5

On Tue, 2016-05-24 at 11:22 -0400, Laine Stump wrote: I like having a single exit point for the function, plus if the function ends up having to allocate (and consequently release) memory in the future it doesn't have to be changed. ... Which is a good argument for using "cleanup" from the very beginning, I guess. Changed :) Probably not that important, since you're supposed to check the return value first - if the function returns <0 and you go ahead and poke at the data anyway, then you're just asking for trouble. I've added it anyway because it can't possibly hurt :) I've addressed your comments and pushed the changes after chopping up into smaller and more focused commits. Thanks for reviewing! --  Andrea Bolognani Software Engineer - Virtualization Team

On 05/24/2016 07:11 AM, Andrea Bolognani wrote: ACK, although it currently doesn't matter (I checked and made sure that the memory at pci_dev.physical_function is free'd even if the PHYSICAL_FUNCTION flag isn't set)