spi: rockchip: check return value of dmaengine_prep_slave_sg

We should check return value of dmaengine_prep_slave_sg, otherwise
we take risk of null pointer.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 9a5c51764833..aa8528e9840c 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -436,7 +436,7 @@ static void rockchip_spi_dma_txcb(void *data)
         spin_unlock_irqrestore(&rs->lock, flags);
 }
 
-static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
+static int rockchip_spi_prepare_dma(struct rockchip_spi *rs)
 {
         unsigned long flags;
         struct dma_slave_config rxconf, txconf;
@@ -459,6 +459,8 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
                                 rs->dma_rx.ch,
                                 rs->rx_sg.sgl, rs->rx_sg.nents,
                                 rs->dma_rx.direction, DMA_PREP_INTERRUPT);
+                if (!rxdesc)
+                        return -EINVAL;
 
                 rxdesc->callback = rockchip_spi_dma_rxcb;
                 rxdesc->callback_param = rs;
@@ -476,6 +478,11 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
                                 rs->dma_tx.ch,
                                 rs->tx_sg.sgl, rs->tx_sg.nents,
                                 rs->dma_tx.direction, DMA_PREP_INTERRUPT);
+                if (!txdesc) {
+                        if (rxdesc)
+                                dmaengine_terminate_sync(rs->dma_rx.ch);
+                        return -EINVAL;
+                }
 
                 txdesc->callback = rockchip_spi_dma_txcb;
                 txdesc->callback_param = rs;
@@ -497,6 +504,8 @@ static void rockchip_spi_prepare_dma(struct rockchip_spi *rs)
                 dmaengine_submit(txdesc);
                 dma_async_issue_pending(rs->dma_tx.ch);
         }
+
+        return 0;
 }
 
 static void rockchip_spi_config(struct rockchip_spi *rs)
@@ -610,12 +619,12 @@ static int rockchip_spi_transfer_one(
         if (rs->use_dma) {
                 if (rs->tmode == CR0_XFM_RO) {
                         /* rx: dma must be prepared first */
-                        rockchip_spi_prepare_dma(rs);
+                        ret = rockchip_spi_prepare_dma(rs);
                         spi_enable_chip(rs, 1);
                 } else {
                         /* tx or tr: spi must be enabled first */
                         spi_enable_chip(rs, 1);
-                        rockchip_spi_prepare_dma(rs);
+                        ret = rockchip_spi_prepare_dma(rs);
                 }
         } else {
                 spi_enable_chip(rs, 1);