Re: [PATCH vhost 11/16] vdpa/mlx5: Move mr mutex out of mr struct

[Eugenio Perez Martin]

On Thu, Sep 28, 2023 at 6:50 PM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
> The mutex is named like it is supposed to protect only the mkey but in
> reality it is a global lock for all mr resources.
>
> Shift the mutex to it's rightful location (struct mlx5_vdpa_dev) and
> give it a more appropriate name.
>

Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>

> Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> ---
>  drivers/vdpa/mlx5/core/mlx5_vdpa.h |  4 ++--
>  drivers/vdpa/mlx5/core/mr.c        | 13 +++++++------
>  drivers/vdpa/mlx5/core/resources.c |  6 +++---
>  3 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index 01d4ee58ccb1..9c6ac42c21e1 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -34,8 +34,6 @@ struct mlx5_vdpa_mr {
>         /* state of dvq mr */
>         bool initialized;
>
> -       /* serialize mkey creation and destruction */
> -       struct mutex mkey_mtx;
>         bool user_mr;
>  };
>
> @@ -94,6 +92,8 @@ struct mlx5_vdpa_dev {
>         u32 generation;
>
>         struct mlx5_vdpa_mr mr;
> +       /* serialize mr access */
> +       struct mutex mr_mtx;
>         struct mlx5_control_vq cvq;
>         struct workqueue_struct *wq;
>         unsigned int group2asid[MLX5_VDPA_NUMVQ_GROUPS];
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 6f29e8eaabb1..abd6a6fb122f 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -509,11 +509,11 @@ static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_
>  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
>                           struct mlx5_vdpa_mr *mr)
>  {
> -       mutex_lock(&mr->mkey_mtx);
> +       mutex_lock(&mvdev->mr_mtx);
>
>         _mlx5_vdpa_destroy_mr(mvdev, mr);
>
> -       mutex_unlock(&mr->mkey_mtx);
> +       mutex_unlock(&mvdev->mr_mtx);
>  }
>
>  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
> @@ -550,9 +550,10 @@ int mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
>  {
>         int err;
>
> -       mutex_lock(&mvdev->mr.mkey_mtx);
> +       mutex_lock(&mvdev->mr_mtx);
>         err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> -       mutex_unlock(&mvdev->mr.mkey_mtx);
> +       mutex_unlock(&mvdev->mr_mtx);
> +
>         return err;
>  }
>
> @@ -563,14 +564,14 @@ int mlx5_vdpa_handle_set_map(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *io
>         int err = 0;
>
>         *change_map = false;
> -       mutex_lock(&mr->mkey_mtx);
> +       mutex_lock(&mvdev->mr_mtx);
>         if (mr->initialized) {
>                 mlx5_vdpa_info(mvdev, "memory map update\n");
>                 *change_map = true;
>         }
>         if (!*change_map)
>                 err = _mlx5_vdpa_create_mr(mvdev, mr, iotlb);
> -       mutex_unlock(&mr->mkey_mtx);
> +       mutex_unlock(&mvdev->mr_mtx);
>
>         return err;
>  }
> diff --git a/drivers/vdpa/mlx5/core/resources.c b/drivers/vdpa/mlx5/core/resources.c
> index d5a59c9035fb..5c5a41b64bfc 100644
> --- a/drivers/vdpa/mlx5/core/resources.c
> +++ b/drivers/vdpa/mlx5/core/resources.c
> @@ -256,7 +256,7 @@ int mlx5_vdpa_alloc_resources(struct mlx5_vdpa_dev *mvdev)
>                 mlx5_vdpa_warn(mvdev, "resources already allocated\n");
>                 return -EINVAL;
>         }
> -       mutex_init(&mvdev->mr.mkey_mtx);
> +       mutex_init(&mvdev->mr_mtx);
>         res->uar = mlx5_get_uars_page(mdev);
>         if (IS_ERR(res->uar)) {
>                 err = PTR_ERR(res->uar);
> @@ -301,7 +301,7 @@ int mlx5_vdpa_alloc_resources(struct mlx5_vdpa_dev *mvdev)
>  err_uctx:
>         mlx5_put_uars_page(mdev, res->uar);
>  err_uars:
> -       mutex_destroy(&mvdev->mr.mkey_mtx);
> +       mutex_destroy(&mvdev->mr_mtx);
>         return err;
>  }
>
> @@ -318,6 +318,6 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev *mvdev)
>         dealloc_pd(mvdev, res->pdn, res->uid);
>         destroy_uctx(mvdev, res->uid);
>         mlx5_put_uars_page(mvdev->mdev, res->uar);
> -       mutex_destroy(&mvdev->mr.mkey_mtx);
> +       mutex_destroy(&mvdev->mr_mtx);
>         res->valid = false;
>  }
> --
> 2.41.0
>