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Message-Id: <1369739242-5944-1-git-send-email-amwang@redhat.com>
Date: Tue, 28 May 2013 19:07:22 +0800
From: Cong Wang <amwang@...hat.com>
To: netdev@...r.kernel.org
Cc: Stephen Hemminger <stephen@...workplumber.org>,
"David S. Miller" <davem@...emloft.net>,
Cong Wang <amwang@...hat.com>
Subject: [Patch net-next] vxlan: do real refcnt for vn_sock
From: Cong Wang <amwang@...hat.com>
In commit 553675fb5e9ce3d71a (vxlan: listen on multiple ports),
we use kfree_rcu() to free ->vn_sock, but a) there is no use
of RCU API to access this filed, b) RCU is not enough to do refcnt
here, because in vxlan_leave_group() we drop RTNL lock before
locking the socket, it could be possible that this field is
freed during this period.
So, instead making things complex, just do basic refcnt for
the ->vn_sock, like we do for others.
Cc: Stephen Hemminger <stephen@...workplumber.org>
Cc: David S. Miller <davem@...emloft.net>
Signed-off-by: Cong Wang <amwang@...hat.com>
---
diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 5ed64d4..73a674e 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -83,9 +83,8 @@ static unsigned int vxlan_net_id;
/* per UDP socket information */
struct vxlan_sock {
struct hlist_node hlist;
- struct rcu_head rcu;
struct work_struct del_work;
- unsigned int refcnt;
+ atomic_t refcnt;
struct socket *sock;
struct hlist_head vni_list[VNI_HASH_SIZE];
};
@@ -164,14 +163,30 @@ static inline struct hlist_head *vs_head(struct net *net, __be16 port)
return &vn->sock_list[hash_32(ntohs(port), PORT_HASH_BITS)];
}
+static inline void vxlan_sock_get(struct vxlan_sock *vs)
+{
+ atomic_inc(&vs->refcnt);
+}
+
+static inline void vxlan_sock_put(struct vxlan_sock *vs)
+{
+ if (atomic_dec_and_test(&vs->refcnt)) {
+ hlist_del_rcu(&vs->hlist);
+ schedule_work(&vs->del_work);
+ }
+}
+
+
/* Find VXLAN socket based on network namespace and UDP port */
static struct vxlan_sock *vxlan_find_port(struct net *net, __be16 port)
{
struct vxlan_sock *vs;
hlist_for_each_entry_rcu(vs, vs_head(net, port), hlist) {
+ vxlan_sock_get(vs);
if (inet_sk(vs->sock->sk)->inet_sport == port)
return vs;
+ vxlan_sock_put(vs);
}
return NULL;
}
@@ -187,10 +202,13 @@ static struct vxlan_dev *vxlan_find_vni(struct net *net, u32 id, __be16 port)
return NULL;
hlist_for_each_entry_rcu(vxlan, vni_head(vs, id), hlist) {
- if (vxlan->default_dst.remote_vni == id)
+ if (vxlan->default_dst.remote_vni == id) {
+ vxlan_sock_put(vs);
return vxlan;
+ }
}
+ vxlan_sock_put(vs);
return NULL;
}
@@ -926,7 +944,7 @@ static bool route_shortcircuit(struct net_device *dev, struct sk_buff *skb)
return false;
}
-static void vxlan_sock_put(struct sk_buff *skb)
+static void vxlan_sock_destructor(struct sk_buff *skb)
{
sock_put(skb->sk);
}
@@ -940,7 +958,7 @@ static void vxlan_set_owner(struct net_device *dev, struct sk_buff *skb)
skb_orphan(skb);
sock_hold(sk);
skb->sk = sk;
- skb->destructor = vxlan_sock_put;
+ skb->destructor = vxlan_sock_destructor;
}
/* Compute source port for outgoing packet
@@ -1255,10 +1273,14 @@ static int vxlan_open(struct net_device *dev)
struct vxlan_dev *vxlan = netdev_priv(dev);
int err;
+ vxlan_sock_get(vxlan->vn_sock);
+
if (IN_MULTICAST(ntohl(vxlan->default_dst.remote_ip))) {
err = vxlan_join_group(dev);
- if (err)
+ if (err) {
+ vxlan_sock_put(vxlan->vn_sock);
return err;
+ }
}
if (vxlan->age_interval)
@@ -1294,6 +1316,8 @@ static int vxlan_stop(struct net_device *dev)
del_timer_sync(&vxlan->age_timer);
+ vxlan_sock_put(vxlan->vn_sock);
+
vxlan_flush(vxlan);
return 0;
@@ -1447,7 +1471,7 @@ static void vxlan_del_work(struct work_struct *work)
struct vxlan_sock *vs = container_of(work, struct vxlan_sock, del_work);
sk_release_kernel(vs->sock->sk);
- kfree_rcu(vs, rcu);
+ kfree(vs);
}
/* Create new listen socket if needed */
@@ -1503,7 +1527,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, __be16 port)
udp_sk(sk)->encap_rcv = vxlan_udp_encap_recv;
udp_encap_enable();
- vs->refcnt = 1;
+ atomic_set(&vs->refcnt, 1);
return vs;
}
@@ -1592,9 +1616,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
}
vs = vxlan_find_port(net, vxlan->dst_port);
- if (vs)
- ++vs->refcnt;
- else {
+ if (!vs) {
/* Drop lock because socket create acquires RTNL lock */
rtnl_unlock();
vs = vxlan_socket_create(net, vxlan->dst_port);
@@ -1610,12 +1632,7 @@ static int vxlan_newlink(struct net *net, struct net_device *dev,
err = register_netdevice(dev);
if (err) {
- if (--vs->refcnt == 0) {
- rtnl_unlock();
- sk_release_kernel(vs->sock->sk);
- kfree(vs);
- rtnl_lock();
- }
+ vxlan_sock_put(vs);
return err;
}
@@ -1634,10 +1651,7 @@ static void vxlan_dellink(struct net_device *dev, struct list_head *head)
list_del(&vxlan->next);
unregister_netdevice_queue(dev, head);
- if (--vs->refcnt == 0) {
- hlist_del_rcu(&vs->hlist);
- schedule_work(&vs->del_work);
- }
+ vxlan_sock_put(vs);
}
static size_t vxlan_get_size(const struct net_device *dev)
--
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