dmaengine: stm32: 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: df7e762db5f6 ("dmaengine: Add STM32 DMAMUX driver")
Cc: stable@vger.kernel.org	# 4.15
Cc: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://patch.msgid.link/20251117161258.10679-11-johan@kernel.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/stm32/stm32-dmamux.c b/drivers/dma/stm32/stm32-dmamux.c
index 8d77e2a7939a0d0a1c8d12d89db81a1cb5309deb..7911797607824583c7d2e287b5d39e58e2a5fcc8 100644 (file)
--- a/drivers/dma/stm32/stm32-dmamux.c
+++ b/drivers/dma/stm32/stm32-dmamux.c
@@ -90,23 +90,25 @@ static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
        struct stm32_dmamux_data *dmamux = platform_get_drvdata(pdev);
        struct stm32_dmamux *mux;
        u32 i, min, max;
-       int ret;
+       int ret = -EINVAL;
        unsigned long flags;
 
        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;
        }
 
        if (dma_spec->args[0] > dmamux->dmamux_requests) {
                dev_err(&pdev->dev, "invalid mux request number: %d\n",
                        dma_spec->args[0]);
-               return ERR_PTR(-EINVAL);
+               goto err_put_pdev;
        }
 
        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
-       if (!mux)
-               return ERR_PTR(-ENOMEM);
+       if (!mux) {
+               ret = -ENOMEM;
+               goto err_put_pdev;
+       }
 
        spin_lock_irqsave(&dmamux->lock, flags);
        mux->chan_id = find_first_zero_bit(dmamux->dma_inuse,
@@ -133,7 +135,6 @@ static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
        dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", i - 1);
        if (!dma_spec->np) {
                dev_err(&pdev->dev, "can't get dma master\n");
-               ret = -EINVAL;
                goto error;
        }
 
@@ -160,6 +161,8 @@ static void *stm32_dmamux_route_allocate(struct of_phandle_args *dma_spec,
        dev_dbg(&pdev->dev, "Mapping DMAMUX(%u) to DMA%u(%u)\n",
                mux->request, mux->master, mux->chan_id);
 
+       put_device(&pdev->dev);
+
        return mux;
 
 error:
@@ -167,6 +170,9 @@ error:
 
 error_chan_id:
        kfree(mux);
+err_put_pdev:
+       put_device(&pdev->dev);
+
        return ERR_PTR(ret);
 }