Re: [PATCH vhost v2 8/8] vdpa/mlx5: Add mkey leak detection

[Eugenio Perez Martin]

On Tue, Dec 5, 2023 at 11:47 AM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
> Track allocated mrs in a list and show warning when leaks are detected
> on device free or reset.
>
> Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Reviewed-by: Gal Pressman <gal@xxxxxxxxxx>

Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>

> ---
>  drivers/vdpa/mlx5/core/mlx5_vdpa.h |  2 ++
>  drivers/vdpa/mlx5/core/mr.c        | 23 +++++++++++++++++++++++
>  drivers/vdpa/mlx5/net/mlx5_vnet.c  |  2 ++
>  3 files changed, 27 insertions(+)
>
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index 1a0d27b6e09a..50aac8fe57ef 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -37,6 +37,7 @@ struct mlx5_vdpa_mr {
>         bool user_mr;
>
>         refcount_t refcount;
> +       struct list_head mr_list;
>  };
>
>  struct mlx5_vdpa_resources {
> @@ -95,6 +96,7 @@ struct mlx5_vdpa_dev {
>         u32 generation;
>
>         struct mlx5_vdpa_mr *mr[MLX5_VDPA_NUM_AS];
> +       struct list_head mr_list_head;
>         /* serialize mr access */
>         struct mutex mr_mtx;
>         struct mlx5_control_vq cvq;
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index c7dc8914354a..4758914ccf86 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -508,6 +508,8 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_
>
>         vhost_iotlb_free(mr->iotlb);
>
> +       list_del(&mr->mr_list);
> +
>         kfree(mr);
>  }
>
> @@ -560,12 +562,31 @@ void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
>         mutex_unlock(&mvdev->mr_mtx);
>  }
>
> +static void mlx5_vdpa_show_mr_leaks(struct mlx5_vdpa_dev *mvdev)
> +{
> +       struct mlx5_vdpa_mr *mr;
> +
> +       mutex_lock(&mvdev->mr_mtx);
> +
> +       list_for_each_entry(mr, &mvdev->mr_list_head, mr_list) {
> +
> +               mlx5_vdpa_warn(mvdev, "mkey still alive after resource delete: "
> +                                     "mr: %p, mkey: 0x%x, refcount: %u\n",
> +                                      mr, mr->mkey, refcount_read(&mr->refcount));
> +       }
> +
> +       mutex_unlock(&mvdev->mr_mtx);
> +
> +}
> +
>  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
>  {
>         for (int i = 0; i < MLX5_VDPA_NUM_AS; i++)
>                 mlx5_vdpa_update_mr(mvdev, NULL, i);
>
>         prune_iotlb(mvdev->cvq.iotlb);
> +
> +       mlx5_vdpa_show_mr_leaks(mvdev);
>  }
>
>  static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
> @@ -592,6 +613,8 @@ static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
>         if (err)
>                 goto err_iotlb;
>
> +       list_add_tail(&mr->mr_list, &mvdev->mr_list_head);
> +
>         return 0;
>
>  err_iotlb:
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 133cbb66dcfe..778821bab7d9 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -3722,6 +3722,8 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
>         if (err)
>                 goto err_mpfs;
>
> +       INIT_LIST_HEAD(&mvdev->mr_list_head);
> +
>         if (MLX5_CAP_GEN(mvdev->mdev, umem_uid_0)) {
>                 err = mlx5_vdpa_create_dma_mr(mvdev);
>                 if (err)
> --
> 2.42.0
>