From 99dc8e400e93773fb45c57cc969c7be443d98141 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri, 21 Aug 2015 20:02:57 +0200
Subject: [PATCH] serial: sh-sci: Don't call sci_dma_rx_push() if no data has
 arrived

On receive DMA time-out, avoid calling sci_dma_rx_push() if no data was
transferred by the timed out DMA request.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/tty/serial/sh-sci.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index ffcbf6eaf5f98..d8b73e791a554 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1467,10 +1467,11 @@ static void work_fn_rx(struct work_struct *work)
 		dev_dbg(port->dev, "Read %u bytes with cookie %d\n", read,
 			s->active_rx);
 
-		count = sci_dma_rx_push(s, s->rx_buf[new], read);
-
-		if (count)
-			tty_flip_buffer_push(&port->state->port);
+		if (read) {
+			count = sci_dma_rx_push(s, s->rx_buf[new], read);
+			if (count)
+				tty_flip_buffer_push(&port->state->port);
+		}
 
 		spin_unlock_irqrestore(&port->lock, flags);
 
-- 
2.30.2