[PATCH 1/1] serial: pch_uart: Pass correct sg to dma_unmap_sg()

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

A local variable sg is used to store scatterlist pointer in
pch_dma_tx_complete(). The for loop doing Tx byte accounting before
dma_unmap_sg() alters sg in its increment statement. Therefore, the
pointer passed into dma_unmap_sg() won't match to the one given to
dma_map_sg().

To fix the problem, use priv->sg_tx_p directly in dma_unmap_sg()
instead of the local variable.

Fixes: da3564ee027e ("pch_uart: add multi-scatter processing")
Cc: stable@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/pch_uart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 3d54a43768cd..9576ba8bbc40 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -749,7 +749,7 @@ static void pch_dma_tx_complete(void *arg)
 		uart_xmit_advance(port, sg_dma_len(sg));
 
 	async_tx_ack(priv->desc_tx);
-	dma_unmap_sg(port->dev, sg, priv->orig_nent, DMA_TO_DEVICE);
+	dma_unmap_sg(port->dev, priv->sg_tx_p, priv->orig_nent, DMA_TO_DEVICE);
 	priv->tx_dma_use = 0;
 	priv->nent = 0;
 	priv->orig_nent = 0;
-- 
2.30.2