sh: fix Oops in the serial SCI driver

Commit Message

Guennadi Liakhovetski May 21, 2010, 3:22 p.m. UTC

None

Patch

diff --git a/drivers/serial/sh-sci.c b/drivers/serial/sh-sci.c
index 304a877..7b273c9 100644
--- a/drivers/serial/sh-sci.c
+++ b/drivers/serial/sh-sci.c
@@ -1007,8 +1007,9 @@  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);
 }