diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 74bfabe5b453..752dab3356d7 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -111,21 +111,11 @@ static void pty_unthrottle(struct tty_struct *tty)
 static int pty_write(struct tty_struct *tty, const unsigned char *buf, int c)
 {
 	struct tty_struct *to = tty->link;
-	unsigned long flags;
 
-	if (tty->flow.stopped)
+	if (tty->flow.stopped || !c)
 		return 0;
 
-	if (c > 0) {
-		spin_lock_irqsave(&to->port->lock, flags);
-		/* Stuff the data into the input queue of the other end */
-		c = tty_insert_flip_string(to->port, buf, c);
-		spin_unlock_irqrestore(&to->port->lock, flags);
-		/* And shovel */
-		if (c)
-			tty_flip_buffer_push(to->port);
-	}
-	return c;
+	return tty_insert_flip_string_and_push_buffer(to->port, buf, c);
 }
 
 /**
diff --git a/drivers/tty/tty.h b/drivers/tty/tty.h
index b710c5ef89ab..f310a8274df1 100644
--- a/drivers/tty/tty.h
+++ b/drivers/tty/tty.h
@@ -111,4 +111,7 @@ static inline void tty_audit_tiocsti(struct tty_struct *tty, char ch)
 
 ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
 
+int tty_insert_flip_string_and_push_buffer(struct tty_port *port,
+		const unsigned char *chars, size_t cnt);
+
 #endif
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 303a26c1b821..595d8b49c745 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -560,6 +560,37 @@ void tty_flip_buffer_push(struct tty_port *port)
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
+/**
+ * tty_insert_flip_string_and_push_buffer - add characters to the tty buffer and
+ *	push
+ * @port: tty port
+ * @chars: characters
+ * @size: size
+ *
+ * The function combines tty_insert_flip_string() and tty_flip_buffer_push()
+ * with the exception of properly holding the @port->lock.
+ *
+ * To be used only internally (by pty currently).
+ *
+ * Returns: the number added.
+ */
+int tty_insert_flip_string_and_push_buffer(struct tty_port *port,
+		const unsigned char *chars, size_t size)
+{
+	struct tty_bufhead *buf = &port->buf;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	size = tty_insert_flip_string(port, chars, size);
+	if (size)
+		tty_flip_buffer_commit(buf->tail);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	queue_work(system_unbound_wq, &buf->work);
+
+	return size;
+}
+
 /**
  * tty_buffer_init		-	prepare a tty buffer structure
  * @port: tty port to initialise