drm/nouveau: unbind in nouveau_ttm_tt_unpopulate

Doing this in nouveau_ttm_tt_destroy()/nouveau_sgdma_destroy() is to late.

It turned out that this is not a good idea at all because it leaves pointers
to freed up system memory pages in the GART tables of the drivers.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210728130552.2074-3-christian.koenig@amd.com

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -1277,6 +1277,8 @@ nouveau_ttm_tt_unpopulate(struct ttm_device *bdev,
 	if (slave)
 		return;
 
+	nouveau_ttm_tt_unbind(bdev, ttm);
+
 	drm = nouveau_bdev(bdev);
 	dev = drm->dev->dev;
 
@@ -1290,7 +1292,6 @@ nouveau_ttm_tt_destroy(struct ttm_device *bdev,
 #if IS_ENABLED(CONFIG_AGP)
 	struct nouveau_drm *drm = nouveau_bdev(bdev);
 	if (drm->agp.bridge) {
-		ttm_agp_unbind(ttm);
 		ttm_tt_destroy_common(bdev, ttm);
 		ttm_agp_destroy(ttm);
 		return;

drivers/gpu/drm/nouveau/nouveau_sgdma.c

@@ -21,7 +21,6 @@ nouveau_sgdma_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 	struct nouveau_sgdma_be *nvbe = (struct nouveau_sgdma_be *)ttm;
 
 	if (ttm) {
-		nouveau_sgdma_unbind(bdev, ttm);
 		ttm_tt_destroy_common(bdev, ttm);
 		ttm_tt_fini(&nvbe->ttm);
 		kfree(nvbe);