linux-kernel - Re: [PATCH vhost 2/7] vdpa/mlx5: Split function into locked and unlocked variants

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Date:   Fri, 1 Dec 2023 12:46:45 +0100
From:   Eugenio Perez Martin <eperezma@...hat.com>
To:     Dragos Tatulea <dtatulea@...dia.com>
Cc:     "Michael S . Tsirkin" <mst@...hat.com>,
        Jason Wang <jasowang@...hat.com>,
        Si-Wei Liu <si-wei.liu@...cle.com>,
        Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Gal Pressman <galp@...dia.com>,
        Parav Pandit <parav@...dia.com>,
        Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Subject: Re: [PATCH vhost 2/7] vdpa/mlx5: Split function into locked and
 unlocked variants

On Fri, Dec 1, 2023 at 11:49 AM Dragos Tatulea <dtatulea@...dia.com> wrote:
>
> mlx5_vdpa_destroy_mr contains more logic than _mlx5_vdpa_destroy_mr.
> There is no reason for this to be the case. All the logic can go into
> the unlocked variant.
>
> Using the unlocked version is needed in a follow-up patch. And it also
> makes it more consistent with mlx5_vdpa_create_mr.
>
> Signed-off-by: Dragos Tatulea <dtatulea@...dia.com>

Acked-by: Eugenio Pérez <eperezma@...hat.com>

> ---
>  drivers/vdpa/mlx5/core/mr.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/core/mr.c b/drivers/vdpa/mlx5/core/mr.c
> index 2197c46e563a..8c80d9e77935 100644
> --- a/drivers/vdpa/mlx5/core/mr.c
> +++ b/drivers/vdpa/mlx5/core/mr.c
> @@ -498,32 +498,32 @@ static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr
>
>  static void _mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
>  {
> +       if (!mr)
> +               return;
> +
>         if (mr->user_mr)
>                 destroy_user_mr(mvdev, mr);
>         else
>                 destroy_dma_mr(mvdev, mr);
>
> +       for (int i = 0; i < MLX5_VDPA_NUM_AS; i++) {
> +               if (mvdev->mr[i] == mr)
> +                       mvdev->mr[i] = NULL;
> +       }
> +
>         vhost_iotlb_free(mr->iotlb);
> +
> +       kfree(mr);
>  }
>
>  void mlx5_vdpa_destroy_mr(struct mlx5_vdpa_dev *mvdev,
>                           struct mlx5_vdpa_mr *mr)
>  {
> -       if (!mr)
> -               return;
> -
>         mutex_lock(&mvdev->mr_mtx);
>
>         _mlx5_vdpa_destroy_mr(mvdev, mr);
>
> -       for (int i = 0; i < MLX5_VDPA_NUM_AS; i++) {
> -               if (mvdev->mr[i] == mr)
> -                       mvdev->mr[i] = NULL;
> -       }
> -
>         mutex_unlock(&mvdev->mr_mtx);
> -
> -       kfree(mr);
>  }
>
>  void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
> @@ -535,10 +535,7 @@ void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
>         mutex_lock(&mvdev->mr_mtx);
>
>         mvdev->mr[asid] = new_mr;
> -       if (old_mr) {
> -               _mlx5_vdpa_destroy_mr(mvdev, old_mr);
> -               kfree(old_mr);
> -       }
> +       _mlx5_vdpa_destroy_mr(mvdev, old_mr);
>
>         mutex_unlock(&mvdev->mr_mtx);
>
> @@ -546,8 +543,12 @@ void mlx5_vdpa_update_mr(struct mlx5_vdpa_dev *mvdev,
>
>  void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
>  {
> +       mutex_lock(&mvdev->mr_mtx);
> +
>         for (int i = 0; i < MLX5_VDPA_NUM_AS; i++)
> -               mlx5_vdpa_destroy_mr(mvdev, mvdev->mr[i]);
> +               _mlx5_vdpa_destroy_mr(mvdev, mvdev->mr[i]);
> +
> +       mutex_unlock(&mvdev->mr_mtx);
>
>         prune_iotlb(mvdev->cvq.iotlb);
>  }
> --
> 2.42.0
>