drm/nouveau/ttm: don't dereference nvbo::cli, it can outlive client

Potentially responsible for some random OOPSes.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Cc: stable@vger.kernel.org [v4.15+]

drivers/gpu/drm/nouveau/nouveau_bo.c

@@ -214,7 +214,6 @@ nouveau_bo_new(struct nouveau_cli *cli, u64 size, int align,
 	INIT_LIST_HEAD(&nvbo->entry);
 	INIT_LIST_HEAD(&nvbo->vma_list);
 	nvbo->bo.bdev = &drm->ttm.bdev;
-	nvbo->cli = cli;
 
 	/* This is confusing, and doesn't actually mean we want an uncached
 	 * mapping, but is what NOUVEAU_GEM_DOMAIN_COHERENT gets translated

drivers/gpu/drm/nouveau/nouveau_bo.h

@@ -26,8 +26,6 @@ struct nouveau_bo {
 
 	struct list_head vma_list;
 
-	struct nouveau_cli *cli;
-
 	unsigned contig:1;
 	unsigned page:5;
 	unsigned kind:8;

drivers/gpu/drm/nouveau/nouveau_ttm.c

@@ -63,7 +63,7 @@ nouveau_vram_manager_new(struct ttm_mem_type_manager *man,
 			 struct ttm_mem_reg *reg)
 {
 	struct nouveau_bo *nvbo = nouveau_bo(bo);
-	struct nouveau_drm *drm = nvbo->cli->drm;
+	struct nouveau_drm *drm = nouveau_bdev(bo->bdev);
 	struct nouveau_mem *mem;
 	int ret;
 
@@ -103,7 +103,7 @@ nouveau_gart_manager_new(struct ttm_mem_type_manager *man,
 			 struct ttm_mem_reg *reg)
 {
 	struct nouveau_bo *nvbo = nouveau_bo(bo);
-	struct nouveau_drm *drm = nvbo->cli->drm;
+	struct nouveau_drm *drm = nouveau_bdev(bo->bdev);
 	struct nouveau_mem *mem;
 	int ret;
 
@@ -131,7 +131,7 @@ nv04_gart_manager_new(struct ttm_mem_type_manager *man,
 		      struct ttm_mem_reg *reg)
 {
 	struct nouveau_bo *nvbo = nouveau_bo(bo);
-	struct nouveau_drm *drm = nvbo->cli->drm;
+	struct nouveau_drm *drm = nouveau_bdev(bo->bdev);
 	struct nouveau_mem *mem;
 	int ret;