libct/cg/sd: remove logging from resetFailedUnit

Sometimes we call resetFailedUnit as a cleanup measure, and we don't
care if it fails or not. So, move error reporting to its callers, and
ignore error in cases we don't really expect it to succeed.

Signed-off-by: Kir Kolyshkin <[email protected]>
(cherry picked from commit 91b4cd2)
Signed-off-by: Kir Kolyshkin <[email protected]>

libcontainer/cgroups/systemd/common.go

@@ -370,7 +370,10 @@ retry:
 			// In case a unit with the same name exists, this may
 			// be a leftover failed unit. Reset it, so systemd can
 			// remove it, and retry once.
-			resetFailedUnit(cm, unitName)
+			err = resetFailedUnit(cm, unitName)
+			if err != nil {
+				logrus.Warnf("unable to reset failed unit: %v", err)
+			}
 			retry = false
 			goto retry
 		}
@@ -385,11 +388,11 @@ retry:
 		close(statusChan)
 		// Please refer to https://pkg.go.dev/github.com/coreos/go-systemd/v22/dbus#Conn.StartUnit
 		if s != "done" {
-			resetFailedUnit(cm, unitName)
+			_ = resetFailedUnit(cm, unitName)
 			return fmt.Errorf("error creating systemd unit `%s`: got `%s`", unitName, s)
 		}
 	case <-timeout.C:
-		resetFailedUnit(cm, unitName)
+		_ = resetFailedUnit(cm, unitName)
 		return errors.New("Timeout waiting for systemd to create " + unitName)
 	}
 
@@ -420,13 +423,10 @@ func stopUnit(cm *dbusConnManager, unitName string) error {
 	return nil
 }
 
-func resetFailedUnit(cm *dbusConnManager, name string) {
-	err := cm.retryOnDisconnect(func(c *systemdDbus.Conn) error {
+func resetFailedUnit(cm *dbusConnManager, name string) error {
+	return cm.retryOnDisconnect(func(c *systemdDbus.Conn) error {
 		return c.ResetFailedUnitContext(context.TODO(), name)
 	})
-	if err != nil {
-		logrus.Warnf("unable to reset failed unit: %v", err)
-	}
 }
 
 func getUnitTypeProperty(cm *dbusConnManager, unitName string, unitType string, propertyName string) (*systemdDbus.Property, error) {