spi: dw-mid: avoid potential NULL dereference

[ Upstream commit c9dafb27c84412fe4b17c3b94cc4ffeef5df1833 ]

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>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index efff55537d8af56120449cb96710938eaec0bef4..1417f96546ce2e13689f86a38762f421b7aeca9e 100644 (file)
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -151,6 +151,9 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
                                1,
                                DMA_MEM_TO_DEV,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!txdesc)
+               return NULL;
+
        txdesc->callback = dw_spi_dma_done;
        txdesc->callback_param = dws;
 
@@ -173,6 +176,9 @@ static int mid_spi_dma_transfer(struct dw_spi *dws, int cs_change)
                                1,
                                DMA_DEV_TO_MEM,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+       if (!rxdesc)
+               return NULL;
+
        rxdesc->callback = dw_spi_dma_done;
        rxdesc->callback_param = dws;