net: ethernet: mtk_wed: fix possible deadlock if mtk_wed_wo_init fails

Introduce __mtk_wed_detach() in order to avoid a deadlock in
mtk_wed_attach routine if mtk_wed_wo_init fails since both
mtk_wed_attach and mtk_wed_detach run holding hw_lock mutex.

Fixes: 4c5de09eb0d0 ("net: ethernet: mtk_wed: add configure wed wo support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c
index 4ef23ea..a627144 100644 (file)
--- a/drivers/net/ethernet/mediatek/mtk_wed.c
+++ b/drivers/net/ethernet/mediatek/mtk_wed.c
@@ -577,12 +577,10 @@ mtk_wed_deinit(struct mtk_wed_device *dev)
 }
 
 static void
-mtk_wed_detach(struct mtk_wed_device *dev)
+__mtk_wed_detach(struct mtk_wed_device *dev)
 {
        struct mtk_wed_hw *hw = dev->hw;
 
-       mutex_lock(&hw_lock);
-
        mtk_wed_deinit(dev);
 
        mtk_wdma_rx_reset(dev);
@@ -615,6 +613,13 @@ mtk_wed_detach(struct mtk_wed_device *dev)
        module_put(THIS_MODULE);
 
        hw->wed_dev = NULL;
+}
+
+static void
+mtk_wed_detach(struct mtk_wed_device *dev)
+{
+       mutex_lock(&hw_lock);
+       __mtk_wed_detach(dev);
        mutex_unlock(&hw_lock);
 }
 
@@ -1497,8 +1502,10 @@ mtk_wed_attach(struct mtk_wed_device *dev)
                ret = mtk_wed_wo_init(hw);
        }
 out:
-       if (ret)
-               mtk_wed_detach(dev);
+       if (ret) {
+               dev_err(dev->hw->dev, "failed to attach wed device\n");
+               __mtk_wed_detach(dev);
+       }
 unlock:
        mutex_unlock(&hw_lock);