[PATCH AUTOSEL 4.4 165/174] tty: serial: imx: use the sg count from dma_map_sg

[Sasha Levin]

From: Peng Fan <peng.fan@xxxxxxx>

[ Upstream commit 596fd8dffb745afcebc0ec6968e17fe29f02044c ]

The dmaengine_prep_slave_sg needs to use sg count returned
by dma_map_sg, not use sport->dma_tx_nents, because the return
value of dma_map_sg is not always same with "nents".

Fixes: b4cdc8f61beb ("serial: imx: add DMA support for imx6q")
Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
Link: https://lore.kernel.org/r/1573108875-26530-1-git-send-email-peng.fan@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/tty/serial/imx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index d607cb2eb64e..b59d0dafefab 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -545,7 +545,7 @@ static void imx_dma_tx(struct imx_port *sport)
 		dev_err(dev, "DMA mapping error for TX.\n");
 		return;
 	}
-	desc = dmaengine_prep_slave_sg(chan, sgl, sport->dma_tx_nents,
+	desc = dmaengine_prep_slave_sg(chan, sgl, ret,
 					DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
 	if (!desc) {
 		dma_unmap_sg(dev, sgl, sport->dma_tx_nents,
-- 
2.20.1