Re: [libvirt] [PATCH 1/2] nodedev: sysfs: Set PCI_PHYSICAL_FUNCTION flag more carefully

On 05/23/2016 07:53 AM, Andrea Bolognani wrote: >  > The flag was set if virPCIGetPhysicalFunction() did not return > an error; unfortunately, the 'physfn' sysfs file not being > present is not considered an error, which means that the flag > was set pretty much unconditionally.   This behavior is the result of commit c8b1a83605:       https://www.redhat.com/archives/libvir-list/2016-May/msg01348.html   Prior to this, virPCIGetPhysicalFunction had returned the return value  from virPCIGetDeviceAddressFromSysfsLink(), which would be -1 if the  physfn file didn't exist. That patch discards the return value and  hardcodes a "return 0".   I think that virPCIGetPhysicalFunction should be restored to its  original glory (No, I didn't write it). Either that, or the other caller  to virPCIGetPhysicalFunction (virPCIGetVirtualFunctionInfo) should also  be fixed so that it doesn't crash due to the changed semantics of  virPCIGetPhysicalFunction.   (A more correct fix may be to change the semantics of  virPCIGetPhysicalFunction() to return -1 only in the case of a bonafide  error (OOM, failure to parse the contents of an existing physfn file),  but that would also require modifying  virPCIGetDeviceAddressFromSysfsLink() to return 0/-1 rather than a  virPCIDeviceAddresPtr so that we can tell the difference between "no  physfn" and "there was a physfn but I encountered some other error". In  other words - 1) revert commit c1faf309 (part of the same "coverity  fixes" series as x8b1a83605), then 2) adjust the function to set *bdf =  0 and return 0 when the physfn file doesn't exist.)