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    Subject[PATCH 5.16 0177/1039] tty: serial: atmel: Check return code of dmaengine_submit()
    Date
    From: Tudor Ambarus <tudor.ambarus@microchip.com>

    [ Upstream commit 1e67bd2b8cb90b66e89562598e9c2046246832d3 ]

    The tx_submit() method of struct dma_async_tx_descriptor is entitled
    to do sanity checks and return errors if encountered. It's not the
    case for the DMA controller drivers that this client is using
    (at_h/xdmac), because they currently don't do sanity checks and always
    return a positive cookie at tx_submit() method. In case the controller
    drivers will implement sanity checks and return errors, print a message
    so that the client will be informed that something went wrong at
    tx_submit() level.

    Fixes: 08f738be88bb ("serial: at91: add tx dma support")
    Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
    Acked-by: Richard Genoud <richard.genoud@gmail.com>
    Link: https://lore.kernel.org/r/20211125090028.786832-3-tudor.ambarus@microchip.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/tty/serial/atmel_serial.c | 10 ++++++++++
    1 file changed, 10 insertions(+)

    diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
    index 2c99a47a25357..376f7a9c2868a 100644
    --- a/drivers/tty/serial/atmel_serial.c
    +++ b/drivers/tty/serial/atmel_serial.c
    @@ -1004,6 +1004,11 @@ static void atmel_tx_dma(struct uart_port *port)
    desc->callback = atmel_complete_tx_dma;
    desc->callback_param = atmel_port;
    atmel_port->cookie_tx = dmaengine_submit(desc);
    + if (dma_submit_error(atmel_port->cookie_tx)) {
    + dev_err(port->dev, "dma_submit_error %d\n",
    + atmel_port->cookie_tx);
    + return;
    + }
    }

    if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
    @@ -1258,6 +1263,11 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
    desc->callback_param = port;
    atmel_port->desc_rx = desc;
    atmel_port->cookie_rx = dmaengine_submit(desc);
    + if (dma_submit_error(atmel_port->cookie_rx)) {
    + dev_err(port->dev, "dma_submit_error %d\n",
    + atmel_port->cookie_rx);
    + goto chan_err;
    + }

    return 0;

    --
    2.34.1


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