drm/ttm: Fix buffer object metadata accounting regression v2

A regression was introduced in the 3.3 rc series, commit
"drm/ttm: simplify memory accounting for ttm user v2",
causing the metadata of buffer objects created using the ttm_bo_create()
function to be accounted twice.
That causes massive leaks with the vmwgfx driver running for example
SpecViewperf Catia-03 test 2, eventually killing the app.

Furthermore, the same commit introduces a regression where
metadata accounting is leaked if a buffer object is
initialized with an illegal size. This is also fixed with this commit.

v2: Fixed an error path and removed an unused variable.
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -1204,6 +1204,7 @@ int ttm_bo_init(struct ttm_bo_device *bdev,
 			(*destroy)(bo);
 		else
 			kfree(bo);
+		ttm_mem_global_free(mem_glob, acc_size);
 		return -EINVAL;
 	}
 	bo->destroy = destroy;
@@ -1307,22 +1308,14 @@ int ttm_bo_create(struct ttm_bo_device *bdev,
 			struct ttm_buffer_object **p_bo)
 {
 	struct ttm_buffer_object *bo;
-	struct ttm_mem_global *mem_glob = bdev->glob->mem_glob;
 	size_t acc_size;
 	int ret;
 
-	acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct ttm_buffer_object));
-	ret = ttm_mem_global_alloc(mem_glob, acc_size, false, false);
-	if (unlikely(ret != 0))
-		return ret;
-
 	bo = kzalloc(sizeof(*bo), GFP_KERNEL);
-
-	if (unlikely(bo == NULL)) {
-		ttm_mem_global_free(mem_glob, acc_size);
+	if (unlikely(bo == NULL))
 		return -ENOMEM;
-	}
 
+	acc_size = ttm_bo_acc_size(bdev, size, sizeof(struct ttm_buffer_object));
 	ret = ttm_bo_init(bdev, bo, size, type, placement, page_alignment,
 				buffer_start, interruptible,
 			  persistent_swap_storage, acc_size, NULL, NULL);