Avoid resetting the VF if the netns does not exist

The VF might have been assigned to another running
Pod if the network namespace is not present. In cases
like this, resetting the VF might break the configuration
of the running Pod.
The above scenario might occur when the IPAM plugin takes a lot of time to complete, and the CmdDel gets called
multiple times.

Check if the namespace is still present before resetting the VF

Signed-off-by: Andrea Panattoni <[email protected]>

cmd/sriov/main.go

@@ -270,19 +270,10 @@ func cmdDel(args *skel.CmdArgs) error {
 
 	sm := sriov.NewSriovManager()
 
-	logging.Debug("Reset VF configuration",
-		"func", "cmdDel",
-		"netConf.DeviceID", netConf.DeviceID)
-	/* ResetVFConfig resets a VF administratively. We must run ResetVFConfig
-	   before ReleaseVF because some drivers will error out if we try to
-	   reset netdev VF with trust off. So, reset VF MAC address via PF first.
-	*/
-	if err := sm.ResetVFConfig(netConf); err != nil {
-		return fmt.Errorf("cmdDel() error reseting VF: %q", err)
-	}
+	var netns ns.NetNS
 
 	if !netConf.DPDKMode {
-		netns, err := ns.GetNS(args.Netns)
+		netns, err = ns.GetNS(args.Netns)
 		if err != nil {
 			// according to:
 			// https://github.com/kubernetes/kubernetes/issues/43014#issuecomment-287164444
@@ -301,7 +292,20 @@ func cmdDel(args *skel.CmdArgs) error {
 			return fmt.Errorf("failed to open netns %s: %q", netns, err)
 		}
 		defer netns.Close()
+	}
 
+	logging.Debug("Reset VF configuration",
+		"func", "cmdDel",
+		"netConf.DeviceID", netConf.DeviceID)
+	/* ResetVFConfig resets a VF administratively. We must run ResetVFConfig
+	   before ReleaseVF because some drivers will error out if we try to
+	   reset netdev VF with trust off. So, reset VF MAC address via PF first.
+	*/
+	if err := sm.ResetVFConfig(netConf); err != nil {
+		return fmt.Errorf("cmdDel() error reseting VF: %q", err)
+	}
+
+	if !netConf.DPDKMode {
 		logging.Debug("Release the VF",
 			"func", "cmdDel",
 			"netConf.DeviceID", netConf.DeviceID,