vdp/mlx5: Fix setting the correct dma_device

Before SF support was introduced, the DMA device was equal to
mdev->device which was in essence equal to pdev->dev.

With SF introduction this is no longer true. It has already been
handled for vhost_vdpa since the reference to the dma device can from
within mlx5_vdpa. With virtio_vdpa this broke. To fix this we set the
real dma device when initializing the device.

In addition, for the sake of consistency, previous references in the
code to the dma device are changed to vdev->dma_dev.

Fixes: d13a15d544 ("vdpa/mlx5: Use the correct dma device when registering memory")
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20210606053150.170489-1-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

drivers/vdpa/mlx5/core/mr.c

@@ -219,11 +219,6 @@ static void destroy_indirect_key(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_m
 	mlx5_vdpa_destroy_mkey(mvdev, &mkey->mkey);
 }
 
-static struct device *get_dma_device(struct mlx5_vdpa_dev *mvdev)
-{
-	return &mvdev->mdev->pdev->dev;
-}
-
 static int map_direct_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_direct_mr *mr,
 			 struct vhost_iotlb *iotlb)
 {
@@ -239,7 +234,7 @@ static int map_direct_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_direct_mr
 	u64 pa;
 	u64 paend;
 	struct scatterlist *sg;
-	struct device *dma = get_dma_device(mvdev);
+	struct device *dma = mvdev->vdev.dma_dev;
 
 	for (map = vhost_iotlb_itree_first(iotlb, mr->start, mr->end - 1);
 	     map; map = vhost_iotlb_itree_next(map, start, mr->end - 1)) {
@@ -298,7 +293,7 @@ err_map:
 
 static void unmap_direct_mr(struct mlx5_vdpa_dev *mvdev, struct mlx5_vdpa_direct_mr *mr)
 {
-	struct device *dma = get_dma_device(mvdev);
+	struct device *dma = mvdev->vdev.dma_dev;
 
 	destroy_direct_mr(mvdev, mr);
 	dma_unmap_sg_attrs(dma, mr->sg_head.sgl, mr->nsg, DMA_BIDIRECTIONAL, 0);

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -2032,7 +2032,7 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name)
 			goto err_mtu;
 	}
 
-	mvdev->vdev.dma_dev = mdev->device;
+	mvdev->vdev.dma_dev = &mdev->pdev->dev;
 	err = mlx5_vdpa_alloc_resources(&ndev->mvdev);
 	if (err)
 		goto err_mpfs;