target/linux/generic/backport-5.15/730-17-v6.3-net-ethernet-mtk_wed-fix-possible-deadlock-if-mtk_we.patch

   1 From: Lorenzo Bianconi <lorenzo@kernel.org>
   2 Date: Wed, 7 Dec 2022 15:04:55 +0100
   3 Subject: [PATCH] net: ethernet: mtk_wed: fix possible deadlock if
   4  mtk_wed_wo_init fails
   5
   6 Introduce __mtk_wed_detach() in order to avoid a deadlock in
   7 mtk_wed_attach routine if mtk_wed_wo_init fails since both
   8 mtk_wed_attach and mtk_wed_detach run holding hw_lock mutex.
   9
  10 Fixes: 4c5de09eb0d0 ("net: ethernet: mtk_wed: add configure wed wo support")
  11 Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
  12 Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
  13 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
  14 ---
  15
  16 --- a/drivers/net/ethernet/mediatek/mtk_wed.c
  17 +++ b/drivers/net/ethernet/mediatek/mtk_wed.c
  18 @@ -619,12 +619,10 @@ mtk_wed_deinit(struct mtk_wed_device *de
  19  }
  20
  21  static void
  22 -mtk_wed_detach(struct mtk_wed_device *dev)
  23 +__mtk_wed_detach(struct mtk_wed_device *dev)
  24  {
  25         struct mtk_wed_hw *hw = dev->hw;
  26
  27 -       mutex_lock(&hw_lock);
  28 -
  29         mtk_wed_deinit(dev);
  30
  31         mtk_wdma_rx_reset(dev);
  32 @@ -657,6 +655,13 @@ mtk_wed_detach(struct mtk_wed_device *de
  33         module_put(THIS_MODULE);
  34
  35         hw->wed_dev = NULL;
  36 +}
  37 +
  38 +static void
  39 +mtk_wed_detach(struct mtk_wed_device *dev)
  40 +{
  41 +       mutex_lock(&hw_lock);
  42 +       __mtk_wed_detach(dev);
  43         mutex_unlock(&hw_lock);
  44  }
  45
  46 @@ -1538,8 +1543,10 @@ mtk_wed_attach(struct mtk_wed_device *de
  47                 ret = mtk_wed_wo_init(hw);
  48         }
  49  out:
  50 -       if (ret)
  51 -               mtk_wed_detach(dev);
  52 +       if (ret) {
  53 +               dev_err(dev->hw->dev, "failed to attach wed device\n");
  54 +               __mtk_wed_detach(dev);
  55 +       }
  56  unlock:
  57         mutex_unlock(&hw_lock);
  58