spi: dw-mid: avoid potential NULL dereference

commit c9dafb27c84412fe4b17c3b94cc4ffeef5df1833 upstream.

When DMA descriptor allocation fails we should not try to assign any fields in
the bad descriptor. The patch adds the necessary checks for that.

Fixes: 7063c0d942a1 (spi/dw_spi: add DMA support)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index a67d37c7e3c00f9518694f267aa75efd5c73398a..22ca08a18b9e73c1436d27df246d850aa004d4cf 100644 (file)
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -139,6 +139,9 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_tx(struct dw_spi *dws)
                                1,
                                DMA_MEM_TO_DEV,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!txdesc)
+               return NULL;
+
        txdesc->callback = dw_spi_dma_tx_done;
        txdesc->callback_param = dws;
 
@@ -184,6 +187,9 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws)
                                1,
                                DMA_DEV_TO_MEM,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!rxdesc)
+               return NULL;
+
        rxdesc->callback = dw_spi_dma_rx_done;
        rxdesc->callback_param = dws;