serial: pch_uart: fix tty-kref leak in dma-rx path

commit 19b85cfb190eb9980eaf416bff96aef4159a430e upstream.

Fix tty_kref leak when tty_buffer_request room fails in dma-rx path.

Note that the tty ref isn't really needed anymore, but as the leak has
always been there, fixing it before removing should makes it easier to
backport the fix.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 2e99f79..5a3fa3a 100644 (file)
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -646,11 +646,12 @@ static int dma_push_rx(struct eg20t_port *priv, int size)
                dev_warn(port->dev, "Rx overrun: dropping %u bytes\n",
                         size - room);
        if (!room)
-               return room;
+               goto out;
 
        tty_insert_flip_string(tty, sg_virt(&priv->sg_rx), size);
 
        port->icount.rx += room;
+out:
        tty_kref_put(tty);
 
        return room;