[PATCHv2 8/9] spi: stm32: fix potential dereference null return value

Amelie Delaunay
2017-06-27T15:45:20Z

This patch fixes the usage of rx_dma_desc and tx_dma_desc pointers
returned by dmaengine_prep_slave_sg, which can be null.

Detected by CoverityScan, CID#1446587 ("Dereference null return value")

Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
---
drivers/spi/spi-stm32.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index fdbc648..bee74e3 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -775,9 +775,6 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
xfer->rx_sg.nents,
rx_dma_conf.direction,
DMA_PREP_INTERRUPT);
-
- rx_dma_desc->callback = stm32_spi_dma_cb;
- rx_dma_desc->callback_param = spi;
}

tx_dma_desc = NULL;
@@ -790,11 +787,6 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
xfer->tx_sg.nents,
tx_dma_conf.direction,
DMA_PREP_INTERRUPT);
-
- if (spi->cur_comm == SPI_SIMPLEX_TX) {
- tx_dma_desc->callback = stm32_spi_dma_cb;
- tx_dma_desc->callback_param = spi;
- }
}

if ((spi->tx_buf && !tx_dma_desc) ||
@@ -802,6 +794,9 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
goto dma_desc_error;

if (rx_dma_desc) {
+ rx_dma_desc->callback = stm32_spi_dma_cb;
+ rx_dma_desc->callback_param = spi;
+
if (dma_submit_error(dmaengine_submit(rx_dma_desc))) {
dev_err(spi->dev, "Rx DMA submit failed\n");
goto dma_desc_error;
@@ -811,6 +806,11 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
}

if (tx_dma_desc) {
+ if (spi->cur_comm == SPI_SIMPLEX_TX) {
+ tx_dma_desc->callback = stm32_spi_dma_cb;
+ tx_dma_desc->callback_param = spi;
+ }
+
if (dma_submit_error(dmaengine_submit(tx_dma_desc))) {
dev_err(spi->dev, "Tx DMA submit failed\n");
goto dma_submit_error;
--
1.9.1