Nick Piggin <npiggin@xxxxxxx> wrote: > Nack, just drop the BUG_ON. I can do that. > I don't know what you mean by "untrustworthy answer". I was thinking that the answer you get from radix_tree_tag_get() may be invalid if the tag chain is being modified as you read it. So if you do: rcu_read_lock() ... x = radix_tree_tag_get(r, i, t); ... y = radix_tree_tag_get(r, i, t); ... rcu_read_unlock() Then you can't guarantee that x == y, even though you were holding the RCU read lock. As you suggested, I'll try and come up with a comment modification to this effect. David -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>