From 4e645b47c4f000a503b9c90163ad905786b9bc1d Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 1 Dec 2017 00:21:02 +0100 Subject: [PATCH 02/11] netfilter: core: make nf_unregister_net_hooks simple wrapper again This reverts commit d3ad2c17b4047 ("netfilter: core: batch nf_unregister_net_hooks synchronize_net calls"). Nothing wrong with it. However, followup patch will delay freeing of hooks with call_rcu, so all synchronize_net() calls become obsolete and there is no need anymore for this batching. This revert causes a temporary performance degradation when destroying network namespace, but its resolved with the upcoming call_rcu conversion. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/core.c | 59 +++------------------------------------------------- 1 file changed, 3 insertions(+), 56 deletions(-) --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -395,63 +395,10 @@ EXPORT_SYMBOL(nf_register_net_hooks); void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg, unsigned int hookcount) { - struct nf_hook_entries *to_free[16], *p; - struct nf_hook_entries __rcu **pp; - unsigned int i, j, n; + unsigned int i; - mutex_lock(&nf_hook_mutex); - for (i = 0; i < hookcount; i++) { - pp = nf_hook_entry_head(net, ®[i]); - if (!pp) - continue; - - p = nf_entry_dereference(*pp); - if (WARN_ON_ONCE(!p)) - continue; - __nf_unregister_net_hook(p, ®[i]); - } - mutex_unlock(&nf_hook_mutex); - - do { - n = min_t(unsigned int, hookcount, ARRAY_SIZE(to_free)); - - mutex_lock(&nf_hook_mutex); - - for (i = 0, j = 0; i < hookcount && j < n; i++) { - pp = nf_hook_entry_head(net, ®[i]); - if (!pp) - continue; - - p = nf_entry_dereference(*pp); - if (!p) - continue; - - to_free[j] = __nf_hook_entries_try_shrink(pp); - if (to_free[j]) - ++j; - } - - mutex_unlock(&nf_hook_mutex); - - if (j) { - unsigned int nfq; - - synchronize_net(); - - /* need 2nd synchronize_net() if nfqueue is used, skb - * can get reinjected right before nf_queue_hook_drop() - */ - nfq = nf_queue_nf_hook_drop(net); - if (nfq) - synchronize_net(); - - for (i = 0; i < j; i++) - kvfree(to_free[i]); - } - - reg += n; - hookcount -= n; - } while (hookcount > 0); + for (i = 0; i < hookcount; i++) + nf_unregister_net_hook(net, ®[i]); } EXPORT_SYMBOL(nf_unregister_net_hooks);