sh: fix Oops in the serial SCI driver

Fix an Oops, triggering, if the DMA buffer allocation for the Rx channel in
sh-sci.c fails.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/serial/sh-sci.c b/drivers/serial/sh-sci.c
index 4f73fb756745..5f90fcd7d107 100644
--- a/drivers/serial/sh-sci.c
+++ b/drivers/serial/sh-sci.c
@@ -1004,8 +1004,9 @@ static void sci_rx_dma_release(struct sci_port *s, bool enable_pio)
         s->chan_rx = NULL;
         s->cookie_rx[0] = s->cookie_rx[1] = -EINVAL;
         dma_release_channel(chan);
-        dma_free_coherent(port->dev, s->buf_len_rx * 2,
-                          sg_virt(&s->sg_rx[0]), sg_dma_address(&s->sg_rx[0]));
+        if (sg_dma_address(&s->sg_rx[0]))
+                dma_free_coherent(port->dev, s->buf_len_rx * 2,
+                                  sg_virt(&s->sg_rx[0]), sg_dma_address(&s->sg_rx[0]));
         if (enable_pio)
                 sci_start_rx(port);
 }