serial: tegra: Fix memory leak on DMA setup failure

If the call to dmaengine_slave_config() fails, then the DMA buffer will
not be freed/unmapped. Fix this by moving the code that stores the
address of the buffer in the tegra_uart_port structure to before the
call to dmaengine_slave_config().

Reported-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
index 3b63f103f0c9b07eca06c548b8c32ccb37d0460a..cf0133ae762dcd68d05fb834a2f481891b06e3dc 100644 (file)
--- a/drivers/tty/serial/serial-tegra.c
+++ b/drivers/tty/serial/serial-tegra.c
@@ -999,6 +999,12 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
                        dma_release_channel(dma_chan);
                        return -ENOMEM;
                }
+               dma_sconfig.src_addr = tup->uport.mapbase;
+               dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+               dma_sconfig.src_maxburst = 4;
+               tup->rx_dma_chan = dma_chan;
+               tup->rx_dma_buf_virt = dma_buf;
+               tup->rx_dma_buf_phys = dma_phys;
        } else {
                dma_phys = dma_map_single(tup->uport.dev,
                        tup->uport.state->xmit.buf, UART_XMIT_SIZE,
@@ -1009,39 +1015,23 @@ static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
                        return -ENOMEM;
                }
                dma_buf = tup->uport.state->xmit.buf;
-       }
-
-       if (dma_to_memory) {
-               dma_sconfig.src_addr = tup->uport.mapbase;
-               dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
-               dma_sconfig.src_maxburst = 4;
-       } else {
                dma_sconfig.dst_addr = tup->uport.mapbase;
                dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
                dma_sconfig.dst_maxburst = 16;
+               tup->tx_dma_chan = dma_chan;
+               tup->tx_dma_buf_virt = dma_buf;
+               tup->tx_dma_buf_phys = dma_phys;
        }
 
        ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
        if (ret < 0) {
                dev_err(tup->uport.dev,
                        "Dma slave config failed, err = %d\n", ret);
-               goto scrub;
+               tegra_uart_dma_channel_free(tup, dma_to_memory);
+               return ret;
        }
 
-       if (dma_to_memory) {
-               tup->rx_dma_chan = dma_chan;
-               tup->rx_dma_buf_virt = dma_buf;
-               tup->rx_dma_buf_phys = dma_phys;
-       } else {
-               tup->tx_dma_chan = dma_chan;
-               tup->tx_dma_buf_virt = dma_buf;
-               tup->tx_dma_buf_phys = dma_phys;
-       }
        return 0;
-
-scrub:
-       tegra_uart_dma_channel_free(tup, dma_to_memory);
-       return ret;
 }
 
 static int tegra_uart_startup(struct uart_port *u)