diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 8f174a7..ec320f7 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -464,34 +464,6 @@
 	return PyBool_FromLong((long) self->seekable);
 }
 
-static Py_ssize_t
-internal_read(int fd, void *buf, size_t count)
-{
-	Py_ssize_t n;
-
-	Py_BEGIN_ALLOW_THREADS
-	errno = 0;
-	n = read(fd, buf, count);
-#ifdef EIO
-	/* Issue #5380: when reading past the end of a pipe created by
-	   openpty(), EIO can be set.  Make it an EOF instead, so that
-	   the normal technique of testing for an empty string can be used.
-	 */
-	if (n == -1 && errno == EIO) {
-		if (isatty(fd)) {
-			n = 0;
-			errno = 0;
-		}
-		else {
-			/* isatty() set errno, restore its value */
-			errno = EIO;
-		}
-	}
-#endif
-	Py_END_ALLOW_THREADS
-	return n;
-}
-
 static PyObject *
 fileio_readinto(fileio *self, PyObject *args)
 {
@@ -506,9 +478,12 @@
 	if (!PyArg_ParseTuple(args, "w*", &pbuf))
 		return NULL;
 
-	if (_PyVerify_fd(self->fd))
-		n = internal_read(self->fd, pbuf.buf, pbuf.len);
-	else
+	if (_PyVerify_fd(self->fd)) {
+		Py_BEGIN_ALLOW_THREADS
+		errno = 0;
+		n = read(self->fd, pbuf.buf, pbuf.len);
+		Py_END_ALLOW_THREADS
+	} else
 		n = -1;
 	PyBuffer_Release(&pbuf);
 	if (n < 0) {
@@ -585,9 +560,12 @@
 				break;
 			}
 		}
-		n = internal_read(self->fd,
-				  PyBytes_AS_STRING(result) + total,
-				  newsize - total);
+		Py_BEGIN_ALLOW_THREADS
+		errno = 0;
+		n = read(self->fd,
+			 PyBytes_AS_STRING(result) + total,
+			 newsize - total);
+		Py_END_ALLOW_THREADS
 		if (n == 0)
 			break;
 		if (n < 0) {
@@ -639,9 +617,12 @@
 		return NULL;
 	ptr = PyBytes_AS_STRING(bytes);
 
-	if (_PyVerify_fd(self->fd))
-		n = internal_read(self->fd, ptr, size);
-	else
+	if (_PyVerify_fd(self->fd)) {
+		Py_BEGIN_ALLOW_THREADS
+		errno = 0;
+		n = read(self->fd, ptr, size);
+		Py_END_ALLOW_THREADS
+	} else
 		n = -1;
 
 	if (n < 0) {