On Mon, May 07, 2018 at 11:36:10PM +0200, Sebastian Reichel wrote:
> This properly unmaps DMA SG on device shutdown.
> 
> Reported-by: Nandor Han <nandor....@ge.com>
> Suggested-by: Nandor Han <nandor....@ge.com>
> Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.co.uk>
> ---
>  drivers/tty/serial/imx.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 3ca767b1162a..6c53e74244ec 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -1425,10 +1425,18 @@ static void imx_uart_shutdown(struct uart_port *port)
>       u32 ucr1, ucr2;
>  
>       if (sport->dma_is_enabled) {
> -             sport->dma_is_rxing = 0;
> -             sport->dma_is_txing = 0;
>               dmaengine_terminate_sync(sport->dma_chan_tx);
> +             if (sport->dma_is_txing) {
> +                     dma_unmap_sg(sport->port.dev, &sport->tx_sgl[0],
> +                                  sport->dma_tx_nents, DMA_TO_DEVICE);
> +                     sport->dma_is_txing = 0;
> +             }

did you find this because the kernel crashed or consumed more and more
memory, or is this "only" a finding of reading the source code? If the
former it would be great to point out in the commit log, if the latter,
I wonder if this is a real problem that warrants a stable backport.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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