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Commit 202e651c authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
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netfilter: conntrack: gre: convert rwlock to rcu 



We can use gre.  Lock is only needed when a new expectation is added.

In case a single spinlock proves to be problematic we can either add one
per netns or use an array of locks combined with net_hash_mix() or similar
to pick the 'correct' one.

But given this is only needed for an expectation rather than per packet
a single one should be ok.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent e2e48b47

include/linux/netfilter/nf_conntrack_proto_gre.h

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ struct nf_conn; 
struct nf_ct_gre_keymap {

	struct list_head list;

	struct nf_conntrack_tuple tuple;

	struct rcu_head rcu;

};



enum grep_conntrack {

net/netfilter/nf_conntrack_proto_gre.c

+15 −22
Original line number Diff line number Diff line
@@ -49,6 +49,8 @@ static const unsigned int gre_timeouts[GRE_CT_MAX] = { 
};



static unsigned int proto_gre_net_id __read_mostly;

/* used when expectation is added */

static DEFINE_SPINLOCK(keymap_lock);



static inline struct netns_proto_gre *gre_pernet(struct net *net)

{
@@ -60,12 +62,12 @@ static void nf_ct_gre_keymap_flush(struct net *net) 
	struct netns_proto_gre *net_gre = gre_pernet(net);

	struct nf_ct_gre_keymap *km, *tmp;



	write_lock_bh(&net_gre->keymap_lock);

	spin_lock_bh(&keymap_lock);

	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {

		list_del(&km->list);

		kfree(km);

		list_del_rcu(&km->list);

		kfree_rcu(km, rcu);

	}

	write_unlock_bh(&net_gre->keymap_lock);

	spin_unlock_bh(&keymap_lock);

}



static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
@@ -85,14 +87,12 @@ static __be16 gre_keymap_lookup(struct net *net, struct nf_conntrack_tuple *t) 
	struct nf_ct_gre_keymap *km;

	__be16 key = 0;



	read_lock_bh(&net_gre->keymap_lock);

	list_for_each_entry(km, &net_gre->keymap_list, list) {

	list_for_each_entry_rcu(km, &net_gre->keymap_list, list) {

		if (gre_key_cmpfn(km, t)) {

			key = km->tuple.src.u.gre.key;

			break;

		}

	}

	read_unlock_bh(&net_gre->keymap_lock);



	pr_debug("lookup src key 0x%x for ", key);

	nf_ct_dump_tuple(t);
@@ -112,14 +112,10 @@ int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir, 
	kmp = &ct_pptp_info->keymap[dir];

	if (*kmp) {

		/* check whether it's a retransmission */

		read_lock_bh(&net_gre->keymap_lock);

		list_for_each_entry(km, &net_gre->keymap_list, list) {

			if (gre_key_cmpfn(km, t) && km == *kmp) {

				read_unlock_bh(&net_gre->keymap_lock);

		list_for_each_entry_rcu(km, &net_gre->keymap_list, list) {

			if (gre_key_cmpfn(km, t) && km == *kmp)

				return 0;

		}

		}

		read_unlock_bh(&net_gre->keymap_lock);

		pr_debug("trying to override keymap_%s for ct %p\n",

			 dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);

		return -EEXIST;
@@ -134,9 +130,9 @@ int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir, 
	pr_debug("adding new entry %p: ", km);

	nf_ct_dump_tuple(&km->tuple);



	write_lock_bh(&net_gre->keymap_lock);

	spin_lock_bh(&keymap_lock);

	list_add_tail(&km->list, &net_gre->keymap_list);

	write_unlock_bh(&net_gre->keymap_lock);

	spin_unlock_bh(&keymap_lock);



	return 0;

}
@@ -145,24 +141,22 @@ EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add); 
/* destroy the keymap entries associated with specified master ct */

void nf_ct_gre_keymap_destroy(struct nf_conn *ct)

{

	struct net *net = nf_ct_net(ct);

	struct netns_proto_gre *net_gre = gre_pernet(net);

	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);

	enum ip_conntrack_dir dir;



	pr_debug("entering for ct %p\n", ct);



	write_lock_bh(&net_gre->keymap_lock);

	spin_lock_bh(&keymap_lock);

	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {

		if (ct_pptp_info->keymap[dir]) {

			pr_debug("removing %p from list\n",

				 ct_pptp_info->keymap[dir]);

			list_del(&ct_pptp_info->keymap[dir]->list);

			kfree(ct_pptp_info->keymap[dir]);

			list_del_rcu(&ct_pptp_info->keymap[dir]->list);

			kfree_rcu(ct_pptp_info->keymap[dir], rcu);

			ct_pptp_info->keymap[dir] = NULL;

		}

	}

	write_unlock_bh(&net_gre->keymap_lock);

	spin_unlock_bh(&keymap_lock);

}

EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
@@ -365,7 +359,6 @@ static int gre_init_net(struct net *net) 
	struct nf_proto_net *nf = &net_gre->nf;

	int i;



	rwlock_init(&net_gre->keymap_lock);

	INIT_LIST_HEAD(&net_gre->keymap_list);

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

		net_gre->gre_timeouts[i] = gre_timeouts[i];