drm/vmwgfx: Don't refcount cotable lookups during command buffer validation

The typical pattern of these lookups are
-Lookup
-Put on validate list if not already there.
-Unreference
And since we are the exclusive user of the context during lookup time,
we can be sure that the resource will stay alive during the sequence.
So avoid taking a reference during lookup, and also avoid unreferencing
when done. There are two users outside of command buffer validation and
those are refcounted explicitly.

Signed-off-by: Thomas Hellstrom <[e-mail]>
Reviewed-by: Sinclair Yeh <[e-mail]>

drivers/gpu/drm/vmwgfx/vmwgfx_context.c

···
 	if (cotable_type >= SVGA_COTABLE_DX10_MAX)
 		return ERR_PTR(-EINVAL);
 
-	return vmw_resource_reference
-		(container_of(ctx, struct vmw_user_context, res)->
-		 cotables[cotable_type]);
+	return container_of(ctx, struct vmw_user_context, res)->
+		cotables[cotable_type];
 }
 
 /**

drivers/gpu/drm/vmwgfx/vmwgfx_execbuf.c

···
 				continue;
 
 			ret = vmw_resource_val_add(sw_context, res);
-			vmw_resource_unreference(&res);
 			if (unlikely(ret != 0))
 				return ret;
 		}
···
 
 	cotable_res = vmw_context_cotable(ctx_node->ctx, SVGA_COTABLE_DXQUERY);
 	ret = vmw_cotable_notify(cotable_res, cmd->q.queryId);
-	vmw_resource_unreference(&cotable_res);
 
 	return ret;
 }
···
 
 	res = vmw_context_cotable(ctx_node->ctx, vmw_view_cotables[view_type]);
 	ret = vmw_cotable_notify(res, cmd->defined_id);
-	vmw_resource_unreference(&res);
 	if (unlikely(ret != 0))
 		return ret;
 
···
 	res = vmw_context_cotable(ctx_node->ctx, vmw_so_cotables[so_type]);
 	cmd = container_of(header, typeof(*cmd), header);
 	ret = vmw_cotable_notify(res, cmd->defined_id);
-	vmw_resource_unreference(&res);
 
 	return ret;
 }
···
 
 	res = vmw_context_cotable(ctx_node->ctx, SVGA_COTABLE_DXSHADER);
 	ret = vmw_cotable_notify(res, cmd->body.shaderId);
-	vmw_resource_unreference(&res);
 	if (ret)
 		return ret;
 

drivers/gpu/drm/vmwgfx/vmwgfx_shader.c

···
 
 	res = &shader->res;
 	shader->ctx = ctx;
-	shader->cotable = vmw_context_cotable(ctx, SVGA_COTABLE_DXSHADER);
+	shader->cotable = vmw_resource_reference
+		(vmw_context_cotable(ctx, SVGA_COTABLE_DXSHADER));
 	shader->id = user_key;
 	shader->committed = false;
 	INIT_LIST_HEAD(&shader->cotable_head);

drivers/gpu/drm/vmwgfx/vmwgfx_so.c

···
 	res = &view->res;
 	view->ctx = ctx;
 	view->srf = vmw_resource_reference(srf);
-	view->cotable = vmw_context_cotable(ctx, vmw_view_cotables[view_type]);
+	view->cotable = vmw_resource_reference
+		(vmw_context_cotable(ctx, vmw_view_cotables[view_type]));
 	view->view_type = view_type;
 	view->view_id = user_key;
 	view->cmd_size = cmd_size;