.release = ipath_diag_release
 };
 
+static ssize_t ipath_diagpkt_write(struct file *fp,
+                                  const char __user *data,
+                                  size_t count, loff_t *off);
+
+static struct file_operations diagpkt_file_ops = {
+       .owner = THIS_MODULE,
+       .write = ipath_diagpkt_write,
+};
+
+static atomic_t diagpkt_count = ATOMIC_INIT(0);
+static struct cdev *diagpkt_cdev;
+static struct class_device *diagpkt_class_dev;
+
 int ipath_diag_add(struct ipath_devdata *dd)
 {
        char name[16];
+       int ret = 0;
+
+       if (atomic_inc_return(&diagpkt_count) == 1) {
+               ret = ipath_cdev_init(IPATH_DIAGPKT_MINOR,
+                                     "ipath_diagpkt", &diagpkt_file_ops,
+                                     &diagpkt_cdev, &diagpkt_class_dev);
+
+               if (ret) {
+                       ipath_dev_err(dd, "Couldn't create ipath_diagpkt "
+                                     "device: %d", ret);
+                       goto done;
+               }
+       }
 
        snprintf(name, sizeof(name), "ipath_diag%d", dd->ipath_unit);
 
-       return ipath_cdev_init(IPATH_DIAG_MINOR_BASE + dd->ipath_unit, name,
-                              &diag_file_ops, &dd->diag_cdev,
-                              &dd->diag_class_dev);
+       ret = ipath_cdev_init(IPATH_DIAG_MINOR_BASE + dd->ipath_unit, name,
+                             &diag_file_ops, &dd->diag_cdev,
+                             &dd->diag_class_dev);
+       if (ret)
+               ipath_dev_err(dd, "Couldn't create %s device: %d",
+                             name, ret);
+
+done:
+       return ret;
 }
 
 void ipath_diag_remove(struct ipath_devdata *dd)
 {
+       if (atomic_dec_and_test(&diagpkt_count))
+               ipath_cdev_cleanup(&diagpkt_cdev, &diagpkt_class_dev);
+
        ipath_cdev_cleanup(&dd->diag_cdev, &dd->diag_class_dev);
 }
 
        return ret;
 }
 
-static ssize_t ipath_diagpkt_write(struct file *fp,
-                                  const char __user *data,
-                                  size_t count, loff_t *off);
-
-static struct file_operations diagpkt_file_ops = {
-       .owner = THIS_MODULE,
-       .write = ipath_diagpkt_write,
-};
-
-static struct cdev *diagpkt_cdev;
-static struct class_device *diagpkt_class_dev;
-
-int __init ipath_diagpkt_add(void)
-{
-       return ipath_cdev_init(IPATH_DIAGPKT_MINOR,
-                              "ipath_diagpkt", &diagpkt_file_ops,
-                              &diagpkt_cdev, &diagpkt_class_dev);
-}
-
-void __exit ipath_diagpkt_remove(void)
-{
-       ipath_cdev_cleanup(&diagpkt_cdev, &diagpkt_class_dev);
-}
-
 /**
  * ipath_diagpkt_write - write an IB packet
  * @fp: the diag data device file pointer