On 21/02/20 13:59, Stefan Hajnoczi wrote: > 1. It doesn't crash if the node is currently not on a list. > 2. It clears the node's linked list pointers so that future linked > list operations (like QLIST_SAFE_REMOVE()) aren't accidentally > performed on stale pointers. > > The node has a long lifespan and will be inserted into ready_lists > multiple times. We need to safely remove it from ready_list to protect > against a corruption the next time the node is inserted into a > ready_list again:
Ah, so the one I singled out is for (2) (we know the node is currently on a list), while the one below is for (1). Would it make sense to move (2) to Q*_REMOVE_*? We can do it separately after this pull request. > /* Add a handler to a ready list */ > static void add_ready_handler(AioHandlerList *ready_list, > AioHandler *node, > int revents) > { > QLIST_SAFE_REMOVE(node, node_ready); /* remove from nested parent's > list */ > ^---- would cause corruption if node->node_ready was stale! > > Would you like me to add a comment? No, it's okay. Paolo