Check SR-IOV VF before validating VF MTU, simplify unit test

Signed-off-by: Masaharu Kanda <kanlkan.naklnak@gmail.com>

Author: kanlkan

pkg/driver/dra_hooks.go

@@ -278,23 +278,21 @@ func (np *NetworkDriver) prepareResourceClaim(ctx context.Context, claim *resour
 		// For SR-IOV VFs, the requested MTU must not exceed the parent PF's MTU.
 		// Otherwise the claim is rejected so the Pod fails fast instead of being
 		// created with an illegal MTU configuration.
-		if deviceCfg.NetworkInterfaceConfigInPod.Interface.MTU != nil {
+		if deviceCfg.NetworkInterfaceConfigInPod.Interface.MTU != nil && inventory.IsSriovVf(ifName) {
 			pfName, err := inventory.GetPFInterfaceName(ifName)
 			if err != nil {
-				// Not an SR-IOV VF, or the parent PF cannot be determined. This is
-				// expected for regular interfaces, so skip the check and only log it.
-				klog.V(4).Infof("skipping SR-IOV VF MTU check for interface %s: %v", ifName, err)
-			} else {
-				pfLink, err := nlHandle.LinkByName(pfName)
-				if err != nil {
-					errorList = append(errorList, fmt.Errorf("failed to get netlink to parent PF %s of VF %s: %v", pfName, ifName, err))
-					continue
-				}
-				requestedMTU := int(*deviceCfg.NetworkInterfaceConfigInPod.Interface.MTU)
-				if err := validateVFMTU(ifName, pfName, requestedMTU, pfLink.Attrs().MTU); err != nil {
-					errorList = append(errorList, err)
-					continue
-				}
+				errorList = append(errorList, fmt.Errorf("failed to determine parent PF for SR-IOV VF %s: %v", ifName, err))
+				continue
+			}
+			pfLink, err := nlHandle.LinkByName(pfName)
+			if err != nil {
+				errorList = append(errorList, fmt.Errorf("failed to get netlink to parent PF %s of VF %s: %v", pfName, ifName, err))
+				continue
+			}
+			requestedMTU := int(*deviceCfg.NetworkInterfaceConfigInPod.Interface.MTU)
+			if err := validateVFMTU(ifName, pfName, requestedMTU, pfLink.Attrs().MTU); err != nil {
+				errorList = append(errorList, err)
+				continue
 			}
 		}
 

pkg/driver/dra_hooks_test.go

@@ -307,18 +307,8 @@ func TestValidateVFMTU(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			err := validateVFMTU("eth1", "eth0", tc.requestedMTU, tc.pfMTU)
-			if tc.wantErr {
-				if err == nil {
-					t.Fatalf("validateVFMTU() expected error, got nil")
-				}
-				want := fmt.Sprintf("requested MTU %d for SR-IOV VF eth1 exceeds parent PF eth0 MTU %d", tc.requestedMTU, tc.pfMTU)
-				if err.Error() != want {
-					t.Errorf("validateVFMTU() error = %q, want %q", err.Error(), want)
-				}
-				return
-			}
-			if err != nil {
-				t.Errorf("validateVFMTU() unexpected error: %v", err)
+			if (err != nil) != tc.wantErr {
+				t.Errorf("validateVFMTU() error = %v, wantErr %v", err, tc.wantErr)
 			}
 		})
 	}

pkg/inventory/sysfs.go

@@ -112,6 +112,11 @@ func isSriovVf(name string, syspath string) bool {
 	return info.Mode()&os.ModeSymlink != 0
 }
 
+// IsSriovVf reports whether a network interface is a SR-IOV Virtual Function.
+func IsSriovVf(name string) bool {
+	return isSriovVf(name, sysnetPath)
+}
+
 // getPFInterfaceNameFromSysfs returns the name of the Physical Function (PF) network
 // interface for a given SR-IOV Virtual Function (VF) interface, using basePath as the
 // root of the sysfs net directory (e.g. /sys/class/net). It returns an error if the