drm/radeon: fix VMID use tracking

Otherwise we allocate a new VMID on nearly every submit.
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -867,6 +867,8 @@ struct radeon_vm {
 	struct radeon_fence		*fence;
 	/* last flush or NULL if we still need to flush */
 	struct radeon_fence		*last_flush;
+	/* last use of vmid */
+	struct radeon_fence		*last_id_use;
 };
 
 struct radeon_vm_manager {

drivers/gpu/drm/radeon/radeon_gart.c

@@ -713,7 +713,7 @@ struct radeon_fence *radeon_vm_grab_id(struct radeon_device *rdev,
 	unsigned i;
 
 	/* check if the id is still valid */
-	if (vm->fence && vm->fence == rdev->vm_manager.active[vm->id])
+	if (vm->last_id_use && vm->last_id_use == rdev->vm_manager.active[vm->id])
 		return NULL;
 
 	/* we definately need to flush */
@@ -769,6 +769,9 @@ void radeon_vm_fence(struct radeon_device *rdev,
 
 	radeon_fence_unref(&vm->fence);
 	vm->fence = radeon_fence_ref(fence);
+
+	radeon_fence_unref(&vm->last_id_use);
+	vm->last_id_use = radeon_fence_ref(fence);
 }
 
 /**
@@ -1303,6 +1306,8 @@ void radeon_vm_init(struct radeon_device *rdev, struct radeon_vm *vm)
 {
 	vm->id = 0;
 	vm->fence = NULL;
+	vm->last_flush = NULL;
+	vm->last_id_use = NULL;
 	mutex_init(&vm->mutex);
 	INIT_LIST_HEAD(&vm->list);
 	INIT_LIST_HEAD(&vm->va);
@@ -1341,5 +1346,6 @@ void radeon_vm_fini(struct radeon_device *rdev, struct radeon_vm *vm)
 	}
 	radeon_fence_unref(&vm->fence);
 	radeon_fence_unref(&vm->last_flush);
+	radeon_fence_unref(&vm->last_id_use);
 	mutex_unlock(&vm->mutex);
 }