dmaengine: lpc18xx-dmamux: fix device leak on route allocation

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>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Link: https://patch.msgid.link/20251117161258.10679-8-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/lpc18xx-dmamux.c b/drivers/dma/lpc18xx-dmamux.c
index 2b6436f4b193743dfd31341022b613712c9bf69b..d3ff521951b835828a7f1fbe47986c39a916d7e0 100644 (file)
--- 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)