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Commit d3ad2c17 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: core: batch nf_unregister_net_hooks synchronize_net calls 



re-add batching in nf_unregister_net_hooks().

Similar as before, just store an array with to-be-free'd rule arrays
on stack, then call synchronize_net once per batch.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 2420b79f

net/netfilter/core.c

+56 −3
Original line number Diff line number Diff line
@@ -395,10 +395,63 @@ EXPORT_SYMBOL(nf_register_net_hooks); 
void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,

			     unsigned int hookcount)

{

	unsigned int i;

	struct nf_hook_entries *to_free[16], *p;

	struct nf_hook_entries __rcu **pp;

	unsigned int i, j, n;



	mutex_lock(&nf_hook_mutex);

	for (i = 0; i < hookcount; i++) {

		pp = nf_hook_entry_head(net, &reg[i]);

		if (!pp)

			continue;



		p = nf_entry_dereference(*pp);

		if (WARN_ON_ONCE(!p))

			continue;

		__nf_unregister_net_hook(p, &reg[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, &reg[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]);

		}



	for (i = 0; i < hookcount; i++)

		nf_unregister_net_hook(net, &reg[i]);

		reg += n;

		hookcount -= n;

	} while (hookcount > 0);

}

EXPORT_SYMBOL(nf_unregister_net_hooks);