[NETFILTER]: nf_nat: switch rwlock to spinlock

Since we're using RCU, all users of nf_nat_lock take a write_lock.
Switch it to a spinlock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c
index c7a985f..dd07362 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_core.c
+++ b/net/ipv4/netfilter/nf_nat_core.c
@@ -31,7 +31,7 @@
 #include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_l4proto.h>
 
-static DEFINE_RWLOCK(nf_nat_lock);
+static DEFINE_SPINLOCK(nf_nat_lock);
 
 static struct nf_conntrack_l3proto *l3proto __read_mostly;
 
@@ -330,12 +330,12 @@ nf_nat_setup_info(struct nf_conn *ct,
                unsigned int srchash;
 
                srchash = hash_by_src(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
-               write_lock_bh(&nf_nat_lock);
+               spin_lock_bh(&nf_nat_lock);
                /* nf_conntrack_alter_reply might re-allocate exntension aera */
                nat = nfct_nat(ct);
                nat->ct = ct;
                hlist_add_head_rcu(&nat->bysource, &bysource[srchash]);
-               write_unlock_bh(&nf_nat_lock);
+               spin_unlock_bh(&nf_nat_lock);
        }
 
        /* It's done. */
@@ -521,14 +521,14 @@ int nf_nat_protocol_register(const struct nf_nat_protocol *proto)
 {
        int ret = 0;
 
-       write_lock_bh(&nf_nat_lock);
+       spin_lock_bh(&nf_nat_lock);
        if (nf_nat_protos[proto->protonum] != &nf_nat_unknown_protocol) {
                ret = -EBUSY;
                goto out;
        }
        rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
  out:
-       write_unlock_bh(&nf_nat_lock);
+       spin_unlock_bh(&nf_nat_lock);
        return ret;
 }
 EXPORT_SYMBOL(nf_nat_protocol_register);
@@ -536,10 +536,10 @@ EXPORT_SYMBOL(nf_nat_protocol_register);
 /* Noone stores the protocol anywhere; simply delete it. */
 void nf_nat_protocol_unregister(const struct nf_nat_protocol *proto)
 {
-       write_lock_bh(&nf_nat_lock);
+       spin_lock_bh(&nf_nat_lock);
        rcu_assign_pointer(nf_nat_protos[proto->protonum],
                           &nf_nat_unknown_protocol);
-       write_unlock_bh(&nf_nat_lock);
+       spin_unlock_bh(&nf_nat_lock);
        synchronize_rcu();
 }
 EXPORT_SYMBOL(nf_nat_protocol_unregister);
@@ -594,10 +594,10 @@ static void nf_nat_cleanup_conntrack(struct nf_conn *ct)
 
        NF_CT_ASSERT(nat->ct->status & IPS_NAT_DONE_MASK);
 
-       write_lock_bh(&nf_nat_lock);
+       spin_lock_bh(&nf_nat_lock);
        hlist_del_rcu(&nat->bysource);
        nat->ct = NULL;
-       write_unlock_bh(&nf_nat_lock);
+       spin_unlock_bh(&nf_nat_lock);
 }
 
 static void nf_nat_move_storage(struct nf_conn *conntrack, void *old)
@@ -609,10 +609,10 @@ static void nf_nat_move_storage(struct nf_conn *conntrack, void *old)
        if (!ct || !(ct->status & IPS_NAT_DONE_MASK))
                return;
 
-       write_lock_bh(&nf_nat_lock);
+       spin_lock_bh(&nf_nat_lock);
        hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource);
        new_nat->ct = ct;
-       write_unlock_bh(&nf_nat_lock);
+       spin_unlock_bh(&nf_nat_lock);
 }
 
 static struct nf_ct_ext_type nat_extend __read_mostly = {
@@ -646,13 +646,13 @@ static int __init nf_nat_init(void)
        }
 
        /* Sew in builtin protocols. */
-       write_lock_bh(&nf_nat_lock);
+       spin_lock_bh(&nf_nat_lock);
        for (i = 0; i < MAX_IP_NAT_PROTO; i++)
                rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
        rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
        rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
        rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
-       write_unlock_bh(&nf_nat_lock);
+       spin_unlock_bh(&nf_nat_lock);
 
        /* Initialize fake conntrack so that NAT will skip it */
        nf_conntrack_untracked.status |= IPS_NAT_DONE_MASK;