[PATCH 7/9] netfilter: nf_ct_expect: use proper RCU list traversal/update APIs

[Pablo Neira Ayuso]

From: Liping Zhang <zlpnob...@gmail.com>

We should use proper RCU list APIs to manipulate help->expectations,
as we can dump the conntrack's expectations via nfnetlink, i.e. in
ctnetlink_exp_ct_dump_table(), where only rcu_read_lock is acquired.

So for list traversal, use hlist_for_each_entry_rcu; for list add/del,
use hlist_add_head_rcu and hlist_del_rcu.

Signed-off-by: Liping Zhang <zlpnob...@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_conntrack_expect.c  | 4 ++--
 net/netfilter/nf_conntrack_netlink.c | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/nf_conntrack_expect.c 
b/net/netfilter/nf_conntrack_expect.c
index 4b2e1fb28bb4..d80073037856 100644
--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -57,7 +57,7 @@ void nf_ct_unlink_expect_report(struct nf_conntrack_expect 
*exp,
        hlist_del_rcu(&exp->hnode);
        net->ct.expect_count--;
 
-       hlist_del(&exp->lnode);
+       hlist_del_rcu(&exp->lnode);
        master_help->expecting[exp->class]--;
 
        nf_ct_expect_event_report(IPEXP_DESTROY, exp, portid, report);
@@ -363,7 +363,7 @@ static void nf_ct_expect_insert(struct nf_conntrack_expect 
*exp)
        /* two references : one for hash insert, one for the timer */
        atomic_add(2, &exp->use);
 
-       hlist_add_head(&exp->lnode, &master_help->expectations);
+       hlist_add_head_rcu(&exp->lnode, &master_help->expectations);
        master_help->expecting[exp->class]++;
 
        hlist_add_head_rcu(&exp->hnode, &nf_ct_expect_hash[h]);
diff --git a/net/netfilter/nf_conntrack_netlink.c 
b/net/netfilter/nf_conntrack_netlink.c
index f78eadba343d..dc7dfd68fafe 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2680,8 +2680,8 @@ ctnetlink_exp_dump_table(struct sk_buff *skb, struct 
netlink_callback *cb)
        last = (struct nf_conntrack_expect *)cb->args[1];
        for (; cb->args[0] < nf_ct_expect_hsize; cb->args[0]++) {
 restart:
-               hlist_for_each_entry(exp, &nf_ct_expect_hash[cb->args[0]],
-                                    hnode) {
+               hlist_for_each_entry_rcu(exp, &nf_ct_expect_hash[cb->args[0]],
+                                        hnode) {
                        if (l3proto && exp->tuple.src.l3num != l3proto)
                                continue;
 
@@ -2732,7 +2732,7 @@ ctnetlink_exp_ct_dump_table(struct sk_buff *skb, struct 
netlink_callback *cb)
        rcu_read_lock();
        last = (struct nf_conntrack_expect *)cb->args[1];
 restart:
-       hlist_for_each_entry(exp, &help->expectations, lnode) {
+       hlist_for_each_entry_rcu(exp, &help->expectations, lnode) {
                if (l3proto && exp->tuple.src.l3num != l3proto)
                        continue;
                if (cb->args[1]) {
-- 
2.1.4