[PATCH] spi : spi-topcliff-pch: Fix to handle empty DMA buffers

From: Aditya Pakki
Date: Wed Mar 13 2019 - 12:55:58 EST


pch_alloc_dma_buf allocated tx, rx DMA buffers which can fail. Further,
these buffers are used without a check. The patch checks for these
failures and sends the error upstream.

Signed-off-by: Aditya Pakki <pakki001@xxxxxxx>
---
drivers/spi/spi-topcliff-pch.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
index fba3f180f233..8a5966963834 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -1299,18 +1299,27 @@ static void pch_free_dma_buf(struct pch_spi_board_data *board_dat,
dma->rx_buf_virt, dma->rx_buf_dma);
}

-static void pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
+static int pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
struct pch_spi_data *data)
{
struct pch_spi_dma_ctrl *dma;
+ int ret;

dma = &data->dma;
+ ret = 0;
/* Get Consistent memory for Tx DMA */
dma->tx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
PCH_BUF_SIZE, &dma->tx_buf_dma, GFP_KERNEL);
+ if (!dma->tx_buf_virt)
+ ret = -ENOMEM;
+
/* Get Consistent memory for Rx DMA */
dma->rx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
PCH_BUF_SIZE, &dma->rx_buf_dma, GFP_KERNEL);
+ if (!dma->rx_buf_virt)
+ ret = -ENOMEM;
+
+ return ret;
}

static int pch_spi_pd_probe(struct platform_device *plat_dev)
@@ -1387,7 +1396,9 @@ static int pch_spi_pd_probe(struct platform_device *plat_dev)

if (use_dma) {
dev_info(&plat_dev->dev, "Use DMA for data transfers\n");
- pch_alloc_dma_buf(board_dat, data);
+ ret = pch_alloc_dma_buf(board_dat, data);
+ if (ret)
+ goto err_spi_register_master;
}

ret = spi_register_master(master);
--
2.17.1