Am 03.09.21 um 08:49 schrieb Pan, Xinhui:
The ret value might be -EBUSY, caller will think lru lock is still
locked but actually NOT. So return -ENOSPC instead. Otherwise we hit
list corruption.
ttm_bo_cleanup_refs might fail too if BO is not idle. If we return 0,
caller(ttm_tt_populate -> ttm_global_swapout ->ttm_device_swapout) will
be stuck as we actually did not free any BO memory. This usually happens
when the fence is not signaled for a long time.
Signed-off-by: xinhui pan <xinhui.pan@xxxxxxx>
Good catch, wanted to rework this for a very long time because of
potential bugs like those.
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/ttm/ttm_bo.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 1fedd0eb67ba..f1367107925b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1159,9 +1159,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
}
if (bo->deleted) {
- ttm_bo_cleanup_refs(bo, false, false, locked);
+ ret = ttm_bo_cleanup_refs(bo, false, false, locked);
ttm_bo_put(bo);
- return 0;
+ return ret == -EBUSY ? -ENOSPC : ret;
}
ttm_bo_move_to_pinned(bo);
@@ -1215,7 +1215,7 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
if (locked)
dma_resv_unlock(bo->base.resv);
ttm_bo_put(bo);
- return ret;
+ return ret == -EBUSY ? -ENOSPC : ret;
}
void ttm_bo_tt_destroy(struct ttm_buffer_object *bo)
