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Date: Mon, 04 Jul 2011 21:20:10 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: victor@...iniac.net
CC: netdev@...r.kernel.org
Subject: [PATCH 1/2] packet: Add helpers to register/unregister ->prot_hook
Signed-off-by: David S. Miller <davem@...emloft.net>
---
net/packet/af_packet.c | 103 +++++++++++++++++++++++++++--------------------
1 files changed, 59 insertions(+), 44 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 461b16f..bb281bf 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -222,6 +222,55 @@ struct packet_skb_cb {
#define PACKET_SKB_CB(__skb) ((struct packet_skb_cb *)((__skb)->cb))
+static inline struct packet_sock *pkt_sk(struct sock *sk)
+{
+ return (struct packet_sock *)sk;
+}
+
+/* register_prot_hook must be invoked with the po->bind_lock held,
+ * or from a context in which asynchronous accesses to the packet
+ * socket is not possible (packet_create()).
+ */
+static void register_prot_hook(struct sock *sk)
+{
+ struct packet_sock *po = pkt_sk(sk);
+ if (!po->running) {
+ dev_add_pack(&po->prot_hook);
+ sock_hold(sk);
+ po->running = 1;
+ }
+}
+
+/* {,__}unregister_prot_hook() must be invoked with the po->bind_lock
+ * held. If the sync parameter is true, we will temporarily drop
+ * the po->bind_lock and do a synchronize_net to make sure no
+ * asynchronous packet processing paths still refer to the elements
+ * of po->prot_hook. If the sync parameter is false, it is the
+ * callers responsibility to take care of this.
+ */
+static void __unregister_prot_hook(struct sock *sk, bool sync)
+{
+ struct packet_sock *po = pkt_sk(sk);
+
+ po->running = 0;
+ __dev_remove_pack(&po->prot_hook);
+ __sock_put(sk);
+
+ if (sync) {
+ spin_unlock(&po->bind_lock);
+ synchronize_net();
+ spin_lock(&po->bind_lock);
+ }
+}
+
+static void unregister_prot_hook(struct sock *sk, bool sync)
+{
+ struct packet_sock *po = pkt_sk(sk);
+
+ if (po->running)
+ __unregister_prot_hook(sk, sync);
+}
+
static inline __pure struct page *pgv_to_page(void *addr)
{
if (is_vmalloc_addr(addr))
@@ -324,11 +373,6 @@ static inline void packet_increment_head(struct packet_ring_buffer *buff)
buff->head = buff->head != buff->frame_max ? buff->head+1 : 0;
}
-static inline struct packet_sock *pkt_sk(struct sock *sk)
-{
- return (struct packet_sock *)sk;
-}
-
static void packet_sock_destruct(struct sock *sk)
{
skb_queue_purge(&sk->sk_error_queue);
@@ -1337,15 +1381,7 @@ static int packet_release(struct socket *sock)
spin_unlock_bh(&net->packet.sklist_lock);
spin_lock(&po->bind_lock);
- if (po->running) {
- /*
- * Remove from protocol table
- */
- po->running = 0;
- po->num = 0;
- __dev_remove_pack(&po->prot_hook);
- __sock_put(sk);
- }
+ unregister_prot_hook(sk, false);
if (po->prot_hook.dev) {
dev_put(po->prot_hook.dev);
po->prot_hook.dev = NULL;
@@ -1392,15 +1428,7 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc
lock_sock(sk);
spin_lock(&po->bind_lock);
- if (po->running) {
- __sock_put(sk);
- po->running = 0;
- po->num = 0;
- spin_unlock(&po->bind_lock);
- dev_remove_pack(&po->prot_hook);
- spin_lock(&po->bind_lock);
- }
-
+ unregister_prot_hook(sk, true);
po->num = protocol;
po->prot_hook.type = protocol;
if (po->prot_hook.dev)
@@ -1413,9 +1441,7 @@ static int packet_do_bind(struct sock *sk, struct net_device *dev, __be16 protoc
goto out_unlock;
if (!dev || (dev->flags & IFF_UP)) {
- dev_add_pack(&po->prot_hook);
- sock_hold(sk);
- po->running = 1;
+ register_prot_hook(sk);
} else {
sk->sk_err = ENETDOWN;
if (!sock_flag(sk, SOCK_DEAD))
@@ -1542,9 +1568,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
if (proto) {
po->prot_hook.type = proto;
- dev_add_pack(&po->prot_hook);
- sock_hold(sk);
- po->running = 1;
+ register_prot_hook(sk);
}
spin_lock_bh(&net->packet.sklist_lock);
@@ -2240,9 +2264,7 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
if (dev->ifindex == po->ifindex) {
spin_lock(&po->bind_lock);
if (po->running) {
- __dev_remove_pack(&po->prot_hook);
- __sock_put(sk);
- po->running = 0;
+ __unregister_prot_hook(sk, false);
sk->sk_err = ENETDOWN;
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_error_report(sk);
@@ -2259,11 +2281,8 @@ static int packet_notifier(struct notifier_block *this, unsigned long msg, void
case NETDEV_UP:
if (dev->ifindex == po->ifindex) {
spin_lock(&po->bind_lock);
- if (po->num && !po->running) {
- dev_add_pack(&po->prot_hook);
- sock_hold(sk);
- po->running = 1;
- }
+ if (po->num)
+ register_prot_hook(sk);
spin_unlock(&po->bind_lock);
}
break;
@@ -2530,10 +2549,8 @@ static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
was_running = po->running;
num = po->num;
if (was_running) {
- __dev_remove_pack(&po->prot_hook);
po->num = 0;
- po->running = 0;
- __sock_put(sk);
+ __unregister_prot_hook(sk, false);
}
spin_unlock(&po->bind_lock);
@@ -2564,11 +2581,9 @@ static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
mutex_unlock(&po->pg_vec_lock);
spin_lock(&po->bind_lock);
- if (was_running && !po->running) {
- sock_hold(sk);
- po->running = 1;
+ if (was_running) {
po->num = num;
- dev_add_pack(&po->prot_hook);
+ register_prot_hook(sk);
}
spin_unlock(&po->bind_lock);
--
1.7.5.4
--
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