From f8ccac0e44934ff9414b31cc3167a5c828afec73 Mon Sep 17 00:00:00 2001 From: Tom Parkin Date: Thu, 31 Jan 2013 23:43:00 +0000 Subject: 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 Signed-off-by: James Chapman Signed-off-by: David S. Miller --- 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 06389d5ff120..73988c070561 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 e62204cad4fe..8eb8f1d47f3a 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 */ }; -- cgit v1.2.3