This is a note to let you know that I've just added the patch titled tty: serial: atmel: Check return code of dmaengine_submit() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tty-serial-atmel-check-return-code-of-dmaengine_subm.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 711888a946ad443d778204449d163cb3fce5e523 Author: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx> Date: Thu Nov 25 11:00:17 2021 +0200 tty: serial: atmel: Check return code of dmaengine_submit() [ 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@xxxxxxxxxxxxx> Acked-by: Richard Genoud <richard.genoud@xxxxxxxxx> Link: https://lore.kernel.org/r/20211125090028.786832-3-tudor.ambarus@xxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 8a909d5561859..da076493b336a 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1002,6 +1002,11 @@ 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) @@ -1262,6 +1267,11 @@ 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;