From 17f2f52be0edb6d1ff5a3675f2bc545aea2dbf76 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Fri, 5 Jun 2009 13:26:21 +0200
Subject: [PATCH] netfilter: ipt_MASQUERADE: remove redundant rwlock
The lock "protects" an assignment and a comparision of an integer.
When the caller of device_cmp() evaluates the result, nat->masq_index
may already have been changed (regardless if the lock is there or not).
So, the lock either has to be held during nf_ct_iterate_cleanup(),
or can be removed.
This does the latter.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
---
net/ipv4/netfilter/ipt_MASQUERADE.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)
diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c
index f389f60cb105..855505d480d2 100644
--- a/net/ipv4/netfilter/ipt_MASQUERADE.c
+++ b/net/ipv4/netfilter/ipt_MASQUERADE.c
@@ -27,9 +27,6 @@ MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Xtables: automatic-address SNAT");
-/* Lock protects masq region inside conntrack */
-static DEFINE_RWLOCK(masq_lock);
-
/* FIXME: Multiple targets. --RR */
static bool masquerade_tg_check(const struct xt_tgchk_param *par)
{
@@ -79,9 +76,7 @@ masquerade_tg(struct sk_buff *skb, const struct xt_target_param *par)
return NF_DROP;
}
- write_lock_bh(&masq_lock);
nat->masq_index = par->out->ifindex;
- write_unlock_bh(&masq_lock);
/* Transfer from original range. */
newrange = ((struct nf_nat_range)
@@ -97,16 +92,11 @@ static int
device_cmp(struct nf_conn *i, void *ifindex)
{
const struct nf_conn_nat *nat = nfct_nat(i);
- int ret;
if (!nat)
return 0;
- read_lock_bh(&masq_lock);
- ret = (nat->masq_index == (int)(long)ifindex);
- read_unlock_bh(&masq_lock);
-
- return ret;
+ return nat->masq_index == (int)(long)ifindex;
}
static int masq_device_event(struct notifier_block *this,
--
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