Hi Johan.

On 11/17/25 18:12, Johan Hovold wrote:

Make sure to drop the reference taken when looking up the DMA mux platform device during route allocation.

Note that holding a reference to a device does not prevent its driver data from going away so there is no point in keeping the reference.

Fixes: e5f4ae84be74 ("dmaengine: add driver for lpc18xx dmamux") Cc: stable@vger.kernel.org # 4.3 Signed-off-by: Johan Hovold johan@kernel.org

---

drivers/dma/lpc18xx-dmamux.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/lpc18xx-dmamux.c b/drivers/dma/lpc18xx-dmamux.c index 2b6436f4b193..d3ff521951b8 100644 --- a/drivers/dma/lpc18xx-dmamux.c +++ b/drivers/dma/lpc18xx-dmamux.c @@ -57,30 +57,31 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, struct lpc18xx_dmamux_data *dmamux = platform_get_drvdata(pdev); unsigned long flags; unsigned mux;

• int ret = -EINVAL;

if (dma_spec->args_count != 3) { dev_err(&pdev->dev, "invalid number of dma mux args\n");

• return ERR_PTR(-EINVAL);
  

• goto err_put_pdev;
  

  }

mux = dma_spec->args[0]; if (mux >= dmamux->dma_master_requests) { dev_err(&pdev->dev, "invalid mux number: %d\n", dma_spec->args[0]);

• return ERR_PTR(-EINVAL);
  

• goto err_put_pdev;
  

  }

if (dma_spec->args[1] > LPC18XX_DMAMUX_MAX_VAL) { dev_err(&pdev->dev, "invalid dma mux value: %d\n", dma_spec->args[1]);

• return ERR_PTR(-EINVAL);
  

• goto err_put_pdev;
  

  }

/* The of_node_put() will be done in the core for the node */ dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0); if (!dma_spec->np) { dev_err(&pdev->dev, "can't get dma master\n");

• return ERR_PTR(-EINVAL);
  

• goto err_put_pdev;
  

  }

spin_lock_irqsave(&dmamux->lock, flags); @@ -89,7 +90,8 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, dev_err(&pdev->dev, "dma request %u busy with %u.%u\n", mux, mux, dmamux->muxes[mux].value); of_node_put(dma_spec->np);

• return ERR_PTR(-EBUSY);
  

• ret = -EBUSY;
  

• goto err_put_pdev;
  

  }

dmamux->muxes[mux].busy = true; @@ -106,7 +108,14 @@ static void *lpc18xx_dmamux_reserve(struct of_phandle_args *dma_spec, dev_dbg(&pdev->dev, "mapping dmamux %u.%u to dma request %u\n", mux, dmamux->muxes[mux].value, mux);

• put_device(&pdev->dev);
• return &dmamux->muxes[mux];

+err_put_pdev:

• put_device(&pdev->dev);
• return ERR_PTR(ret); }

static int lpc18xx_dmamux_probe(struct platform_device *pdev)

Reviewed-by: Vladimir Zapolskiy vz@mleia.com