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l2tp: put tunnel socket release on a workqueue

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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@katalix.com>
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Parkin 2013-01-31 23:43:00 +00:00 committed by David S. Miller
parent 188d1f76d0
commit f8ccac0e44
2 changed files with 61 additions and 44 deletions
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103
net/l2tp/l2tp_core.c
View File

@ -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;
/* 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);
l2tp_tunnel_closeall(tunnel);
l2tp_tunnel_dec_refcount(tunnel);
/* Call the original destructor */
if (sk->sk_destruct)
(*sk->sk_destruct)(sk);
/* We're finished with the socket */
l2tp_tunnel_dec_refcount(tunnel);
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);

2
net/l2tp/l2tp_core.h
View File

@ -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 */
};