vdpa/mlx5: Add error code for suspend/resume VQ

Instead of blindly calling suspend/resume_vqs(), make then return error
codes.

To keep compatibility, keep suspending or resuming VQs on error and
return the last error code. The assumption here is that the error code
would be the same.
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Message-Id: <20240626-stage-vdpa-vq-precreate-v2-17-560c491078df@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/mlx5/net/mlx5_vnet.c

@@ -1526,71 +1526,102 @@ static int setup_vq(struct mlx5_vdpa_net *ndev,
 	return err;
 }
 
-static void suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+static int suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
 	struct mlx5_virtq_attr attr;
+	int err;
 
 	if (!mvq->initialized)
-		return;
+		return 0;
 
 	if (mvq->fw_state != MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY)
-		return;
+		return 0;
 
-	if (modify_virtqueue_state(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND))
-		mlx5_vdpa_warn(&ndev->mvdev, "modify to suspend failed\n");
+	err = modify_virtqueue_state(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND);
+	if (err) {
+		mlx5_vdpa_warn(&ndev->mvdev, "modify to suspend failed, err: %d\n", err);
+		return err;
+	}
 
-	if (query_virtqueue(ndev, mvq, &attr)) {
-		mlx5_vdpa_warn(&ndev->mvdev, "failed to query virtqueue\n");
-		return;
+	err = query_virtqueue(ndev, mvq, &attr);
+	if (err) {
+		mlx5_vdpa_warn(&ndev->mvdev, "failed to query virtqueue, err: %d\n", err);
+		return err;
 	}
+
 	mvq->avail_idx = attr.available_index;
 	mvq->used_idx = attr.used_index;
+
+	return 0;
 }
 
-static void suspend_vqs(struct mlx5_vdpa_net *ndev)
+static int suspend_vqs(struct mlx5_vdpa_net *ndev)
 {
+	int err = 0;
 	int i;
 
-	for (i = 0; i < ndev->cur_num_vqs; i++)
-		suspend_vq(ndev, &ndev->vqs[i]);
+	for (i = 0; i < ndev->cur_num_vqs; i++) {
+		int local_err = suspend_vq(ndev, &ndev->vqs[i]);
+
+		err = local_err ? local_err : err;
+	}
+
+	return err;
 }
 
-static void resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
+	int err;
+
 	if (!mvq->initialized)
-		return;
+		return 0;
 
 	switch (mvq->fw_state) {
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_INIT:
 		/* Due to a FW quirk we need to modify the VQ fields first then change state.
 		 * This should be fixed soon. After that, a single command can be used.
 		 */
-		if (modify_virtqueue(ndev, mvq, 0))
+		err = modify_virtqueue(ndev, mvq, 0);
+		if (err) {
 			mlx5_vdpa_warn(&ndev->mvdev,
-				"modify vq properties failed for vq %u\n", mvq->index);
+				"modify vq properties failed for vq %u, err: %d\n",
+				mvq->index, err);
+			return err;
+		}
 		break;
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND:
 		if (!is_resumable(ndev)) {
 			mlx5_vdpa_warn(&ndev->mvdev, "vq %d is not resumable\n", mvq->index);
-			return;
+			return -EINVAL;
 		}
 		break;
 	case MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY:
-		return;
+		return 0;
 	default:
 		mlx5_vdpa_warn(&ndev->mvdev, "resume vq %u called from bad state %d\n",
 			       mvq->index, mvq->fw_state);
-		return;
+		return -EINVAL;
 	}
 
-	if (modify_virtqueue_state(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY))
-		mlx5_vdpa_warn(&ndev->mvdev, "modify to resume failed for vq %u\n", mvq->index);
+	err = modify_virtqueue_state(ndev, mvq, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY);
+	if (err)
+		mlx5_vdpa_warn(&ndev->mvdev, "modify to resume failed for vq %u, err: %d\n",
+			       mvq->index, err);
+
+	return err;
 }
 
-static void resume_vqs(struct mlx5_vdpa_net *ndev)
+static int resume_vqs(struct mlx5_vdpa_net *ndev)
 {
-	for (int i = 0; i < ndev->cur_num_vqs; i++)
-		resume_vq(ndev, &ndev->vqs[i]);
+	int err = 0;
+
+	for (int i = 0; i < ndev->cur_num_vqs; i++) {
+		int local_err = resume_vq(ndev, &ndev->vqs[i]);
+
+		err = local_err ? local_err : err;
+	}
+
+	return err;
 }
 
 static void teardown_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)