drm/ttm: handle the SYSTEM->TT path in same place as others.

This just consolidates the code making the flow easier to understand
and also helps when moving move to the driver side.

Reviewed-by: Christian König <christian.koenig@amd.com>.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200924051845.397177-3-airlied@gmail.com

drivers/gpu/drm/ttm/ttm_bo.c

@@ -265,24 +265,22 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 			if (ret)
 				goto out_err;
 		}
-
-		if (bo->mem.mem_type == TTM_PL_SYSTEM) {
-			if (bdev->driver->move_notify)
-				bdev->driver->move_notify(bo, evict, mem);
-			bo->mem = *mem;
-			goto moved;
-		}
 	}
 
 	if (bdev->driver->move_notify)
 		bdev->driver->move_notify(bo, evict, mem);
 
-	if (old_man->use_tt && new_man->use_tt)
+	if (old_man->use_tt && new_man->use_tt) {
+		if (bo->mem.mem_type == TTM_PL_SYSTEM) {
+			ttm_bo_assign_mem(bo, mem);
+			ret = 0;
+		} else
 			ret = ttm_bo_move_ttm(bo, ctx, mem);
-	else if (bdev->driver->move)
+	} else if (bdev->driver->move) {
 		ret = bdev->driver->move(bo, evict, ctx, mem);
-	else
+	} else {
 		ret = ttm_bo_move_memcpy(bo, ctx, mem);
+	}
 
 	if (ret) {
 		if (bdev->driver->move_notify) {
@@ -294,7 +292,6 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 		goto out_err;
 	}
 
-moved:
 	ctx->bytes_moved += bo->num_pages << PAGE_SHIFT;
 	return 0;