diff --git a/kernel/file_ops.c b/kernel/file_ops.c
index 4be82f59..8f3acab0 100644
--- a/kernel/file_ops.c
+++ b/kernel/file_ops.c
@@ -526,9 +526,18 @@ long hfi1_file_ioctl(void *private_data, unsigned int cmd,
 
 	case HFI1_IOCTL_TID_INVAL_READ:
 		dkprintf("%s: HFI1_IOCTL_TID_INVAL_READ \n", __FUNCTION__);
-		/* This function is only invovled with the tid mmu caching.
-		 * It is a no-op for us. */
-		ret = 0;
+		if (copy_from_user(&tinfo,
+				   (struct hfi11_tid_info __user *)arg,
+				   sizeof(tinfo)))
+			return -EFAULT;
+
+		ret = hfi1_user_exp_rcv_invalid(fd, &tinfo);
+		if (ret)
+			break;
+		addr = arg + offsetof(struct hfi1_tid_info, tidcnt);
+		if (copy_to_user((void __user *)addr, &tinfo.tidcnt,
+				 sizeof(tinfo.tidcnt)))
+			ret = -EFAULT;
 		break;
 
 	case HFI1_IOCTL_RECV_CTRL: