On Tue, May 5, 2015 at 11:17 PM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote:
> Function tegra_uart_dma_channel_allocate() does not check that
> dma_map_single() mapped the DMA buffer correctly. Add a check for this
> and appropriate error handling.
>
> Furthermore, if dmaengine_slave_config() (called by
> tegra_uart_dma_channel_allocate()) fails, then memory allocated/mapped
> is not freed/unmapped. Therefore, call tegra_uart_dma_channel_free()
> instead of just dma_release_channel() if dmaengine_slave_config() fails.
>
> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> ---
> drivers/tty/serial/serial-tegra.c | 51 +++++++++++++++++++++------------------
> 1 file changed, 28 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
> index 96378da9aefc..3b63f103f0c9 100644
> --- a/drivers/tty/serial/serial-tegra.c
> +++ b/drivers/tty/serial/serial-tegra.c
> @@ -949,6 +949,28 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
> return 0;
> }
>
> +static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
> + bool dma_to_memory)
> +{
> + if (dma_to_memory) {
> + dmaengine_terminate_all(tup->rx_dma_chan);
> + dma_release_channel(tup->rx_dma_chan);
> + dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
> + tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
> + tup->rx_dma_chan = NULL;
> + tup->rx_dma_buf_phys = 0;
> + tup->rx_dma_buf_virt = NULL;
> + } else {
> + dmaengine_terminate_all(tup->tx_dma_chan);
> + dma_release_channel(tup->tx_dma_chan);
> + dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
> + UART_XMIT_SIZE, DMA_TO_DEVICE);
> + tup->tx_dma_chan = NULL;
> + tup->tx_dma_buf_phys = 0;
> + tup->tx_dma_buf_virt = NULL;
> + }
> +}
> +
> static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
> bool dma_to_memory)
> {
> @@ -981,6 +1003,11 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
> dma_phys = dma_map_single(tup->uport.dev,
> tup->uport.state->xmit.buf, UART_XMIT_SIZE,
> DMA_TO_DEVICE);
> + if (dma_mapping_error(tup->uport.dev, dma_phys)) {
> + dev_err(tup->uport.dev, "dma_map_single tx failed\n");
> + dma_release_channel(dma_chan);
> + return -ENOMEM;
Is -ENOMEM the error code we want to return here?
IIUC dma_buf will be leaked if an error occurs here because it has not
been assigned to your structure and will therefore be ignored when
tegra_uart_dma_channel_free() is called.
Since we have a "scrub" label at the end of this function, I think I'd
also prefer if this block and the one before could jump to error
labels as well for consistency.
Otherwise, pretty nice series, comprehensive and easy to read.
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