[PATCH 2/4] drm/virtio: resource teardown tweaks

[Gerd Hoffmann]

Add new virtio_gpu_cleanup_object() helper function for object cleanup.
Wire up callback function for resource unref, do cleanup from callback
when we know the host stopped using the resource.

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h    |  3 ++-
 drivers/gpu/drm/virtio/virtgpu_object.c | 19 ++++++++++----
 drivers/gpu/drm/virtio/virtgpu_vq.c     | 35 ++++++++++++++++++++++---
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 7e69c06e168e..372dd248cf02 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -262,7 +262,7 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 				    struct virtio_gpu_object_array *objs,
 				    struct virtio_gpu_fence *fence);
 void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
-				   uint32_t resource_id);
+				   struct virtio_gpu_object *bo);
 void virtio_gpu_cmd_transfer_to_host_2d(struct virtio_gpu_device *vgdev,
 					uint64_t offset,
 					uint32_t width, uint32_t height,
@@ -355,6 +355,7 @@ void virtio_gpu_fence_event_process(struct virtio_gpu_device *vdev,
 				    u64 last_seq);
 
 /* virtio_gpu_object */
+void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo);
 struct drm_gem_object *virtio_gpu_create_object(struct drm_device *dev,
 						size_t size);
 int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 017a9e0fc3bb..28a161af7503 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -61,6 +61,14 @@ static void virtio_gpu_resource_id_put(struct virtio_gpu_device *vgdev, uint32_t
 	}
 }
 
+void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
+{
+	struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
+
+	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
+	drm_gem_shmem_free_object(&bo->base.base);
+}
+
 static void virtio_gpu_free_object(struct drm_gem_object *obj)
 {
 	struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
@@ -68,11 +76,12 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj)
 
 	if (bo->pages)
 		virtio_gpu_object_detach(vgdev, bo);
-	if (bo->created)
-		virtio_gpu_cmd_unref_resource(vgdev, bo->hw_res_handle);
-	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
-
-	drm_gem_shmem_free_object(obj);
+	if (bo->created) {
+		virtio_gpu_cmd_unref_resource(vgdev, bo);
+		/* completion handler calls virtio_gpu_cleanup_object() */
+		return;
+	}
+	virtio_gpu_cleanup_object(bo);
 }
 
 static const struct drm_gem_object_funcs virtio_gpu_gem_funcs = {
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 6d6d55dc384e..6e8097e4c214 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -152,6 +152,15 @@ static void *virtio_gpu_alloc_cmd(struct virtio_gpu_device *vgdev,
 					 sizeof(struct virtio_gpu_ctrl_hdr), NULL);
 }
 
+static void *virtio_gpu_alloc_cmd_cb(struct virtio_gpu_device *vgdev,
+				     struct virtio_gpu_vbuffer **vbuffer_p,
+				     int size,
+				     virtio_gpu_resp_cb cb)
+{
+	return virtio_gpu_alloc_cmd_resp(vgdev, cb, vbuffer_p, size,
+					 sizeof(struct virtio_gpu_ctrl_hdr), NULL);
+}
+
 static void free_vbuf(struct virtio_gpu_device *vgdev,
 		      struct virtio_gpu_vbuffer *vbuf)
 {
@@ -494,17 +503,37 @@ void virtio_gpu_cmd_create_resource(struct virtio_gpu_device *vgdev,
 	bo->created = true;
 }
 
+static void virtio_gpu_cmd_unref_cb(struct virtio_gpu_device *vgdev,
+				    struct virtio_gpu_vbuffer *vbuf)
+{
+	struct virtio_gpu_object *bo;
+
+	bo = gem_to_virtio_gpu_obj(vbuf->objs->objs[0]);
+	kfree(vbuf->objs);
+	vbuf->objs = NULL;
+
+	virtio_gpu_cleanup_object(bo);
+}
+
 void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
-				   uint32_t resource_id)
+				   struct virtio_gpu_object *bo)
 {
 	struct virtio_gpu_resource_unref *cmd_p;
 	struct virtio_gpu_vbuffer *vbuf;
 
-	cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p));
+	cmd_p = virtio_gpu_alloc_cmd_cb(vgdev, &vbuf, sizeof(*cmd_p),
+					virtio_gpu_cmd_unref_cb);
 	memset(cmd_p, 0, sizeof(*cmd_p));
 
 	cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_UNREF);
-	cmd_p->resource_id = cpu_to_le32(resource_id);
+	cmd_p->resource_id = cpu_to_le32(bo->hw_res_handle);
+
+	/*
+	 * We are in the release callback and do NOT want refcount
+	 * bo, so do NOT use virtio_gpu_array_add_obj().
+	 */
+	vbuf->objs = virtio_gpu_array_alloc(1);
+	vbuf->objs->objs[0] = &bo->base.base;
 
 	virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
 }
-- 
2.18.1