Messages in this thread |  | | Date | Tue, 31 Jul 2018 13:27:01 -0700 | From | Stephen Hemminger <> | Subject | Re: [PATCH v1 3/3] net: WireGuard secure network tunnel |
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On Tue, 31 Jul 2018 21:11:02 +0200 "Jason A. Donenfeld" <Jason@zx2c4.com> wrote:
> +#define push(stack, p, len) ({ \ > + if (rcu_access_pointer(p)) { \ > + BUG_ON(len >= 128); \ > + stack[len++] = rcu_dereference_protected(p, lockdep_is_held(lock)); \ > + } \ > + true; \ > +}) > +static void free_root_node(struct allowedips_node __rcu *top, struct mutex *lock) > +{ > + struct allowedips_node *stack[128], *node; > + unsigned int len; > + > + for (len = 0, push(stack, top, len); len > 0 && (node = stack[--len]) && push(stack, node->bit[0], len) && push(stack, node->bit[1], len);) > + call_rcu_bh(&node->rcu, node_free_rcu); > +}
This looks like you are doing traversal to free a tree. The stack is there so that you do the rcu callbacks in the proper order. Won't this create an lot of RCU work at once?
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