[PATCH 1/3] spi: rockchip: check return value of dmaengine_prep_slave_sg

From: Shawn Lin
Date: Wed Mar 09 2016 - 03:19:37 EST


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

Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>

---

drivers/spi/spi-rockchip.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index eb1bd45..91f44a3 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -437,7 +437,7 @@ 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;
@@ -463,6 +463,8 @@ 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;
@@ -483,6 +485,11 @@ 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;
@@ -504,6 +511,8 @@ 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)
@@ -617,12 +626,12 @@ 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);
--
2.3.7