vdpa/mlx5: Make iotlb helper functions more generic

They will be used in a follow-up patch.

For dup_iotlb, avoid the src == dst case. This is an error.

Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20231018171456.1624030-17-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Author: dtatulea

drivers/vdpa/mlx5/core/mr.c

@@ -454,30 +454,33 @@ static void destroy_dma_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
 	mlx5_vdpa_destroy_mkey(mvdev, mr->mkey);
 }
 
-static int dup_iotlb(struct mlx5_vdpa_dev *mvdev, struct vhost_iotlb *src)
+static int dup_iotlb(struct vhost_iotlb *dst, struct vhost_iotlb *src)
 {
 	struct vhost_iotlb_map *map;
 	u64 start = 0, last = ULLONG_MAX;
 	int err;
 
+	if (dst == src)
+		return -EINVAL;
+
 	if (!src) {
-		err = vhost_iotlb_add_range(mvdev->cvq.iotlb, start, last, start, VHOST_ACCESS_RW);
+		err = vhost_iotlb_add_range(dst, start, last, start, VHOST_ACCESS_RW);
 		return err;
 	}
 
 	for (map = vhost_iotlb_itree_first(src, start, last); map;
 		map = vhost_iotlb_itree_next(map, start, last)) {
-		err = vhost_iotlb_add_range(mvdev->cvq.iotlb, map->start, map->last,
+		err = vhost_iotlb_add_range(dst, map->start, map->last,
 					    map->addr, map->perm);
 		if (err)
 			return err;
 	}
 	return 0;
 }
 
-static void prune_iotlb(struct mlx5_vdpa_dev *mvdev)
+static void prune_iotlb(struct vhost_iotlb *iotlb)
 {
-	vhost_iotlb_del_range(mvdev->cvq.iotlb, 0, ULLONG_MAX);
+	vhost_iotlb_del_range(iotlb, 0, ULLONG_MAX);
 }
 
 static void destroy_user_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_mr *mr)
@@ -544,7 +547,7 @@ void mlx5_vdpa_destroy_mr_resources(struct mlx5_vdpa_dev *mvdev)
 	for (int i = 0; i < MLX5_VDPA_NUM_AS; i++)
 		mlx5_vdpa_destroy_mr(mvdev, mvdev->mr[i]);
 
-	prune_iotlb(mvdev);
+	prune_iotlb(mvdev->cvq.iotlb);
 }
 
 static int _mlx5_vdpa_create_mr(struct mlx5_vdpa_dev *mvdev,
@@ -596,8 +599,8 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
 
 	spin_lock(&mvdev->cvq.iommu_lock);
 
-	prune_iotlb(mvdev);
-	err = dup_iotlb(mvdev, iotlb);
+	prune_iotlb(mvdev->cvq.iotlb);
+	err = dup_iotlb(mvdev->cvq.iotlb, iotlb);
 
 	spin_unlock(&mvdev->cvq.iommu_lock);