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Date: Fri, 1 Feb 2013 09:43:00 +0000
From: Tom Parkin <tparkin@...alix.com>
To: netdev@...r.kernel.org
Cc: jchapman@...alix.com, celston@...alix.com,
Tom Parkin <tparkin@...alix.com>
Subject: [PATCH 1/4] l2tp: put tunnel socket release on a workqueue
To allow l2tp_tunnel_delete to be called from an atomic context, place the
tunnel socket release calls on a workqueue for asynchronous execution.
Tunnel memory is eventually freed in the tunnel socket destructor.
Signed-off-by: Tom Parkin <tparkin@...alix.com>
Signed-off-by: James Chapman <jchapman@...alix.com>
---
net/l2tp/l2tp_core.c | 103 +++++++++++++++++++++++++++++---------------------
net/l2tp/l2tp_core.h | 2 +
2 files changed, 61 insertions(+), 44 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 06389d5..73988c0 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -101,6 +101,7 @@ struct l2tp_skb_cb {
static atomic_t l2tp_tunnel_count;
static atomic_t l2tp_session_count;
+static struct workqueue_struct *l2tp_wq;
/* per-net private data for this module */
static unsigned int l2tp_net_id;
@@ -122,7 +123,6 @@ static inline struct l2tp_net *l2tp_pernet(struct net *net)
return net_generic(net, l2tp_net_id);
}
-
/* Tunnel reference counts. Incremented per session that is added to
* the tunnel.
*/
@@ -1277,6 +1277,7 @@ EXPORT_SYMBOL_GPL(l2tp_xmit_skb);
static void l2tp_tunnel_destruct(struct sock *sk)
{
struct l2tp_tunnel *tunnel;
+ struct l2tp_net *pn;
tunnel = sk->sk_user_data;
if (tunnel == NULL)
@@ -1284,9 +1285,8 @@ static void l2tp_tunnel_destruct(struct sock *sk)
l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: closing...\n", tunnel->name);
- /* Close all sessions */
- l2tp_tunnel_closeall(tunnel);
+ /* Disable udp encapsulation */
switch (tunnel->encap) {
case L2TP_ENCAPTYPE_UDP:
/* No longer an encapsulation socket. See net/ipv4/udp.c */
@@ -1298,17 +1298,23 @@ static void l2tp_tunnel_destruct(struct sock *sk)
}
/* Remove hooks into tunnel socket */
- tunnel->sock = NULL;
sk->sk_destruct = tunnel->old_sk_destruct;
sk->sk_user_data = NULL;
+ tunnel->sock = NULL;
- /* Call the original destructor */
- if (sk->sk_destruct)
- (*sk->sk_destruct)(sk);
+ /* Remove the tunnel struct from the tunnel list */
+ pn = l2tp_pernet(tunnel->l2tp_net);
+ spin_lock_bh(&pn->l2tp_tunnel_list_lock);
+ list_del_rcu(&tunnel->list);
+ spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
+ atomic_dec(&l2tp_tunnel_count);
- /* We're finished with the socket */
+ l2tp_tunnel_closeall(tunnel);
l2tp_tunnel_dec_refcount(tunnel);
+ /* Call the original destructor */
+ if (sk->sk_destruct)
+ (*sk->sk_destruct)(sk);
end:
return;
}
@@ -1382,20 +1388,41 @@ again:
*/
static void l2tp_tunnel_free(struct l2tp_tunnel *tunnel)
{
- struct l2tp_net *pn = l2tp_pernet(tunnel->l2tp_net);
-
BUG_ON(atomic_read(&tunnel->ref_count) != 0);
BUG_ON(tunnel->sock != NULL);
-
l2tp_info(tunnel, L2TP_MSG_CONTROL, "%s: free...\n", tunnel->name);
-
- /* Remove from tunnel list */
- spin_lock_bh(&pn->l2tp_tunnel_list_lock);
- list_del_rcu(&tunnel->list);
kfree_rcu(tunnel, rcu);
- spin_unlock_bh(&pn->l2tp_tunnel_list_lock);
+}
- atomic_dec(&l2tp_tunnel_count);
+/* Workqueue tunnel deletion function */
+static void l2tp_tunnel_del_work(struct work_struct *work)
+{
+ struct l2tp_tunnel *tunnel = NULL;
+ struct socket *sock = NULL;
+ struct sock *sk = NULL;
+
+ tunnel = container_of(work, struct l2tp_tunnel, del_work);
+ sk = l2tp_tunnel_sock_lookup(tunnel);
+ if (!sk)
+ return;
+
+ sock = sk->sk_socket;
+ BUG_ON(!sock);
+
+ /* Force the tunnel socket to close. This will eventually
+ * cause the tunnel to be deleted via the normal socket close
+ * mechanisms when userspace closes the tunnel socket.
+ */
+ inet_shutdown(sock, 2);
+
+ /* If the tunnel's socket was created by the kernel,
+ * close the socket here since the socket was not
+ * created by userspace.
+ */
+ if (sock->file == NULL)
+ inet_release(sock);
+
+ l2tp_tunnel_sock_put(sk);
}
/* Create a socket for the tunnel, if one isn't set up by
@@ -1657,6 +1684,9 @@ int l2tp_tunnel_create(struct net *net, int fd, int version, u32 tunnel_id, u32
sk->sk_allocation = GFP_ATOMIC;
+ /* Init delete workqueue struct */
+ INIT_WORK(&tunnel->del_work, l2tp_tunnel_del_work);
+
/* Add tunnel to our list */
INIT_LIST_HEAD(&tunnel->list);
atomic_inc(&l2tp_tunnel_count);
@@ -1688,33 +1718,7 @@ EXPORT_SYMBOL_GPL(l2tp_tunnel_create);
*/
int l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
{
- int err = -EBADF;
- struct socket *sock = NULL;
- struct sock *sk = NULL;
-
- sk = l2tp_tunnel_sock_lookup(tunnel);
- if (!sk)
- goto out;
-
- sock = sk->sk_socket;
- BUG_ON(!sock);
-
- /* Force the tunnel socket to close. This will eventually
- * cause the tunnel to be deleted via the normal socket close
- * mechanisms when userspace closes the tunnel socket.
- */
- err = inet_shutdown(sock, 2);
-
- /* If the tunnel's socket was created by the kernel,
- * close the socket here since the socket was not
- * created by userspace.
- */
- if (sock->file == NULL)
- err = inet_release(sock);
-
- l2tp_tunnel_sock_put(sk);
-out:
- return err;
+ return (false == queue_work(l2tp_wq, &tunnel->del_work));
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_delete);
@@ -1912,6 +1916,13 @@ static int __init l2tp_init(void)
if (rc)
goto out;
+ l2tp_wq = alloc_workqueue("l2tp", WQ_NON_REENTRANT | WQ_UNBOUND, 0);
+ if (!l2tp_wq) {
+ pr_err("alloc_workqueue failed\n");
+ rc = -ENOMEM;
+ goto out;
+ }
+
pr_info("L2TP core driver, %s\n", L2TP_DRV_VERSION);
out:
@@ -1921,6 +1932,10 @@ out:
static void __exit l2tp_exit(void)
{
unregister_pernet_device(&l2tp_net_ops);
+ if (l2tp_wq) {
+ destroy_workqueue(l2tp_wq);
+ l2tp_wq = NULL;
+ }
}
module_init(l2tp_init);
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index e62204c..8eb8f1d 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -191,6 +191,8 @@ struct l2tp_tunnel {
int fd; /* Parent fd, if tunnel socket
* was created by userspace */
+ struct work_struct del_work;
+
uint8_t priv[0]; /* private data */
};
--
1.7.9.5
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