queue-4.4/spi-spi-topcliff-pch-fix-to-handle-empty-dma-buffers.patch

   1 From 05ad9b5a6b0c285e486b9b9a6fc8e8a0b5836ac4 Mon Sep 17 00:00:00 2001
   2 From: Aditya Pakki <pakki001@umn.edu>
   3 Date: Wed, 13 Mar 2019 11:55:41 -0500
   4 Subject: spi : spi-topcliff-pch: Fix to handle empty DMA buffers
   5
   6 [ Upstream commit f37d8e67f39e6d3eaf4cc5471e8a3d21209843c6 ]
   7
   8 pch_alloc_dma_buf allocated tx, rx DMA buffers which can fail. Further,
   9 these buffers are used without a check. The patch checks for these
  10 failures and sends the error upstream.
  11
  12 Signed-off-by: Aditya Pakki <pakki001@umn.edu>
  13 Signed-off-by: Mark Brown <broonie@kernel.org>
  14 Signed-off-by: Sasha Levin <sashal@kernel.org>
  15 ---
  16  drivers/spi/spi-topcliff-pch.c | 15 +++++++++++++--
  17  1 file changed, 13 insertions(+), 2 deletions(-)
  18
  19 diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
  20 index 93dfcee0f987b..9f30a4ab2004a 100644
  21 --- a/drivers/spi/spi-topcliff-pch.c
  22 +++ b/drivers/spi/spi-topcliff-pch.c
  23 @@ -1326,18 +1326,27 @@ static void pch_free_dma_buf(struct pch_spi_board_data *board_dat,
  24         return;
  25  }
  26
  27 -static void pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
  28 +static int pch_alloc_dma_buf(struct pch_spi_board_data *board_dat,
  29                               struct pch_spi_data *data)
  30  {
  31         struct pch_spi_dma_ctrl *dma;
  32 +       int ret;
  33
  34         dma = &data->dma;
  35 +       ret = 0;
  36         /* Get Consistent memory for Tx DMA */
  37         dma->tx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
  38                                 PCH_BUF_SIZE, &dma->tx_buf_dma, GFP_KERNEL);
  39 +       if (!dma->tx_buf_virt)
  40 +               ret = -ENOMEM;
  41 +
  42         /* Get Consistent memory for Rx DMA */
  43         dma->rx_buf_virt = dma_alloc_coherent(&board_dat->pdev->dev,
  44                                 PCH_BUF_SIZE, &dma->rx_buf_dma, GFP_KERNEL);
  45 +       if (!dma->rx_buf_virt)
  46 +               ret = -ENOMEM;
  47 +
  48 +       return ret;
  49  }
  50
  51  static int pch_spi_pd_probe(struct platform_device *plat_dev)
  52 @@ -1414,7 +1423,9 @@ static int pch_spi_pd_probe(struct platform_device *plat_dev)
  53
  54         if (use_dma) {
  55                 dev_info(&plat_dev->dev, "Use DMA for data transfers\n");
  56 -               pch_alloc_dma_buf(board_dat, data);
  57 +               ret = pch_alloc_dma_buf(board_dat, data);
  58 +               if (ret)
  59 +                       goto err_spi_register_master;
  60         }
  61
  62         ret = spi_register_master(master);
  63 --
  64 2.20.1
  65