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    Subject[PATCH AUTOSEL for 4.14 005/110] dmaengine: fsl-edma: disable clks on all error paths
    Date
    From: Andreas Platschek <andreas.platschek@opentech.at>

    [ Upstream commit 2610acf46b9ed528ec2cacd717bc9d354e452b73 ]

    Previously enabled clks are only disabled if clk_prepare_enable() fails.
    However, there are other error paths were the previously enabled
    clocks are not disabled.

    To fix the problem, fsl_disable_clocks() now takes the number of clocks
    that shall be disabled + unprepared. For existing calls were all clocks
    were already successfully prepared + enabled, DMAMUX_NR is passed to
    disable + unprepare all clocks.

    In error paths were only some clocks were successfully prepared +
    enabled the loop counter is passed, in order to disable + unprepare
    all successfully prepared + enabled clocks.

    Found by Linux Driver Verification project (linuxtesting.org).

    Signed-off-by: Andreas Platschek <andreas.platschek@opentech.at>
    Signed-off-by: Vinod Koul <vinod.koul@intel.com>
    Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
    ---
    drivers/dma/fsl-edma.c | 28 ++++++++++++++--------------
    1 file changed, 14 insertions(+), 14 deletions(-)

    diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c
    index 6775f2c74e25..c7568869284e 100644
    --- a/drivers/dma/fsl-edma.c
    +++ b/drivers/dma/fsl-edma.c
    @@ -863,11 +863,11 @@ static void fsl_edma_irq_exit(
    }
    }

    -static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma)
    +static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma, int nr_clocks)
    {
    int i;

    - for (i = 0; i < DMAMUX_NR; i++)
    + for (i = 0; i < nr_clocks; i++)
    clk_disable_unprepare(fsl_edma->muxclk[i]);
    }

    @@ -904,25 +904,25 @@ static int fsl_edma_probe(struct platform_device *pdev)

    res = platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
    fsl_edma->muxbase[i] = devm_ioremap_resource(&pdev->dev, res);
    - if (IS_ERR(fsl_edma->muxbase[i]))
    + if (IS_ERR(fsl_edma->muxbase[i])) {
    + /* on error: disable all previously enabled clks */
    + fsl_disable_clocks(fsl_edma, i);
    return PTR_ERR(fsl_edma->muxbase[i]);
    + }

    sprintf(clkname, "dmamux%d", i);
    fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
    if (IS_ERR(fsl_edma->muxclk[i])) {
    dev_err(&pdev->dev, "Missing DMAMUX block clock.\n");
    + /* on error: disable all previously enabled clks */
    + fsl_disable_clocks(fsl_edma, i);
    return PTR_ERR(fsl_edma->muxclk[i]);
    }

    ret = clk_prepare_enable(fsl_edma->muxclk[i]);
    - if (ret) {
    - /* disable only clks which were enabled on error */
    - for (; i >= 0; i--)
    - clk_disable_unprepare(fsl_edma->muxclk[i]);
    -
    - dev_err(&pdev->dev, "DMAMUX clk block failed.\n");
    - return ret;
    - }
    + if (ret)
    + /* on error: disable all previously enabled clks */
    + fsl_disable_clocks(fsl_edma, i);

    }

    @@ -976,7 +976,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
    if (ret) {
    dev_err(&pdev->dev,
    "Can't register Freescale eDMA engine. (%d)\n", ret);
    - fsl_disable_clocks(fsl_edma);
    + fsl_disable_clocks(fsl_edma, DMAMUX_NR);
    return ret;
    }

    @@ -985,7 +985,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
    dev_err(&pdev->dev,
    "Can't register Freescale eDMA of_dma. (%d)\n", ret);
    dma_async_device_unregister(&fsl_edma->dma_dev);
    - fsl_disable_clocks(fsl_edma);
    + fsl_disable_clocks(fsl_edma, DMAMUX_NR);
    return ret;
    }

    @@ -1015,7 +1015,7 @@ static int fsl_edma_remove(struct platform_device *pdev)
    fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
    of_dma_controller_free(np);
    dma_async_device_unregister(&fsl_edma->dma_dev);
    - fsl_disable_clocks(fsl_edma);
    + fsl_disable_clocks(fsl_edma, DMAMUX_NR);

    return 0;
    }
    --
    2.11.0
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