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From 4e645b47c4f000a503b9c90163ad905786b9bc1d Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
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 <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
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);
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