drm/ttm: fix adding foreign BOs to the LRU during init v2

If we import a BO with an external reservation object we don't
reserve/unreserve it. So we never add it to the LRU causing a possible
denial of service.

v2: fix typo in commit message
Reviewed-by: NThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -1170,9 +1170,15 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 	if (likely(!ret))
 		ret = ttm_bo_validate(bo, placement, interruptible, false);
 
-	if (!resv)
+	if (!resv) {
 		ttm_bo_unreserve(bo);
 
+	} else if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) {
+		spin_lock(&bo->glob->lru_lock);
+		ttm_bo_add_to_lru(bo);
+		spin_unlock(&bo->glob->lru_lock);
+	}
+
 	if (unlikely(ret))
 		ttm_bo_unref(&bo);