drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing

Rework fencing workflow, starting with virtio_gpu_execbuffer_ioctl.
Stop using ttm helpers, use the virtio_gpu_array_* helpers (which work
on the reservation objects directly) instead.

Also store the object array in struct virtio_gpu_vbuffer, so we
explicitly keep a reference of all buffers used instead of depending
on ttm_bo_put() checking whenever the object is actually idle before
releasing it.

New workflow:

 (1) All gem objects needed by a command are added to a
     virtio_gpu_object_array.
 (2) All reservation objects will be locked (virtio_gpu_array_lock_resv).
 (3) virtio_gpu_fence_emit() completes fence initialization.
 (4) fence gets added to the objects, reservation objects are unlocked
     (virtio_gpu_array_add_fence, virtio_gpu_array_unlock_resv).
 (5) virtio command is submitted to the host.
 (6) The completion callback (virtio_gpu_dequeue_ctrl_func)
     will drop object references and free virtio_gpu_object_array.

v6: rewrite most of the patch.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190829103301.3539-9-kraxel@redhat.com

1 files changed, 18 insertions, 38 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 7f1775b9449e..61b1b55ec508 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -107,16 +107,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 	struct drm_virtgpu_execbuffer *exbuf = data;
 	struct virtio_gpu_device *vgdev = dev->dev_private;
 	struct virtio_gpu_fpriv *vfpriv = drm_file->driver_priv;
-	struct drm_gem_object *gobj;
 	struct virtio_gpu_fence *out_fence;
-	struct virtio_gpu_object *qobj;
 	int ret;
 	uint32_t *bo_handles = NULL;
 	void __user *user_bo_handles = NULL;
-	struct list_head validate_list;
-	struct ttm_validate_buffer *buflist = NULL;
-	int i;
-	struct ww_acquire_ctx ticket;
+	struct virtio_gpu_object_array *buflist = NULL;
 	struct sync_file *sync_file;
 	int in_fence_fd = exbuf->fence_fd;
 	int out_fence_fd = -1;
@@ -157,15 +152,10 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 			return out_fence_fd;
 	}
 
-	INIT_LIST_HEAD(&validate_list);
 	if (exbuf->num_bo_handles) {
-
 		bo_handles = kvmalloc_array(exbuf->num_bo_handles,
-					   sizeof(uint32_t), GFP_KERNEL);
-		buflist = kvmalloc_array(exbuf->num_bo_handles,
-					   sizeof(struct ttm_validate_buffer),
-					   GFP_KERNEL | __GFP_ZERO);
-		if (!bo_handles || !buflist) {
+					    sizeof(uint32_t), GFP_KERNEL);
+		if (!bo_handles) {
 			ret = -ENOMEM;
 			goto out_unused_fd;
 		}
@@ -177,25 +167,21 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 			goto out_unused_fd;
 		}
 
-		for (i = 0; i < exbuf->num_bo_handles; i++) {
-			gobj = drm_gem_object_lookup(drm_file, bo_handles[i]);
-			if (!gobj) {
-				ret = -ENOENT;
-				goto out_unused_fd;
-			}
-
-			qobj = gem_to_virtio_gpu_obj(gobj);
-			buflist[i].bo = &qobj->tbo;
-
-			list_add(&buflist[i].head, &validate_list);
+		buflist = virtio_gpu_array_from_handles(drm_file, bo_handles,
+							exbuf->num_bo_handles);
+		if (!buflist) {
+			ret = -ENOENT;
+			goto out_unused_fd;
 		}
 		kvfree(bo_handles);
 		bo_handles = NULL;
 	}
 
-	ret = virtio_gpu_object_list_validate(&ticket, &validate_list);
-	if (ret)
-		goto out_free;
+	if (buflist) {
+		ret = virtio_gpu_array_lock_resv(buflist);
+		if (ret)
+			goto out_unused_fd;
+	}
 
 	buf = memdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
 	if (IS_ERR(buf)) {
@@ -222,24 +208,18 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 	}
 
 	virtio_gpu_cmd_submit(vgdev, buf, exbuf->size,
-			      vfpriv->ctx_id, out_fence);
-
-	ttm_eu_fence_buffer_objects(&ticket, &validate_list, &out_fence->f);
-
-	/* fence the command bo */
-	virtio_gpu_unref_list(&validate_list);
-	kvfree(buflist);
+			      vfpriv->ctx_id, buflist, out_fence);
 	return 0;
 
 out_memdup:
 	kfree(buf);
 out_unresv:
-	ttm_eu_backoff_reservation(&ticket, &validate_list);
-out_free:
-	virtio_gpu_unref_list(&validate_list);
+	if (buflist)
+		virtio_gpu_array_unlock_resv(buflist);
 out_unused_fd:
 	kvfree(bo_handles);
-	kvfree(buflist);
+	if (buflist)
+		virtio_gpu_array_put_free(buflist);
 
 	if (out_fence_fd >= 0)
 		put_unused_fd(out_fence_fd);