diff options
| -rw-r--r-- | net/l2tp/l2tp_ppp.c | 94 |
1 files changed, 39 insertions, 55 deletions
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c index 0844b86cd0a6..12a0a7162870 100644 --- a/net/l2tp/l2tp_ppp.c +++ b/net/l2tp/l2tp_ppp.c @@ -119,7 +119,6 @@ struct pppol2tp_session { struct mutex sk_lock; /* Protects .sk */ struct sock __rcu *sk; /* Pointer to the session PPPoX socket */ struct sock *__sk; /* Copy of .sk, for cleanup */ - struct rcu_head rcu; /* For asynchronous release */ }; static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb); @@ -157,20 +156,16 @@ static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk) if (!sk) return NULL; - sock_hold(sk); - session = (struct l2tp_session *)(sk->sk_user_data); - if (!session) { - sock_put(sk); - goto out; - } - if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) { - session = NULL; - sock_put(sk); - goto out; + rcu_read_lock(); + session = rcu_dereference_sk_user_data(sk); + if (session && refcount_inc_not_zero(&session->ref_count)) { + rcu_read_unlock(); + WARN_ON_ONCE(session->magic != L2TP_SESSION_MAGIC); + return session; } + rcu_read_unlock(); -out: - return session; + return NULL; } /***************************************************************************** @@ -318,12 +313,12 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m, l2tp_xmit_skb(session, skb); local_bh_enable(); - sock_put(sk); + l2tp_session_dec_refcount(session); return total_len; error_put_sess: - sock_put(sk); + l2tp_session_dec_refcount(session); error: return error; } @@ -377,12 +372,12 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb) l2tp_xmit_skb(session, skb); local_bh_enable(); - sock_put(sk); + l2tp_session_dec_refcount(session); return 1; abort_put_sess: - sock_put(sk); + l2tp_session_dec_refcount(session); abort: /* Free the original skb */ kfree_skb(skb); @@ -393,28 +388,31 @@ abort: * Session (and tunnel control) socket create/destroy. *****************************************************************************/ -static void pppol2tp_put_sk(struct rcu_head *head) -{ - struct pppol2tp_session *ps; - - ps = container_of(head, typeof(*ps), rcu); - sock_put(ps->__sk); -} - /* Really kill the session socket. (Called from sock_put() if * refcnt == 0.) */ static void pppol2tp_session_destruct(struct sock *sk) { - struct l2tp_session *session = sk->sk_user_data; - skb_queue_purge(&sk->sk_receive_queue); skb_queue_purge(&sk->sk_write_queue); +} - if (session) { - sk->sk_user_data = NULL; - if (WARN_ON(session->magic != L2TP_SESSION_MAGIC)) - return; +static void pppol2tp_session_close(struct l2tp_session *session) +{ + struct pppol2tp_session *ps; + + ps = l2tp_session_priv(session); + mutex_lock(&ps->sk_lock); + ps->__sk = rcu_dereference_protected(ps->sk, + lockdep_is_held(&ps->sk_lock)); + RCU_INIT_POINTER(ps->sk, NULL); + mutex_unlock(&ps->sk_lock); + if (ps->__sk) { + /* detach socket */ + rcu_assign_sk_user_data(ps->__sk, NULL); + sock_put(ps->__sk); + + /* drop ref taken when we referenced socket via sk_user_data */ l2tp_session_dec_refcount(session); } } @@ -444,30 +442,13 @@ static int pppol2tp_release(struct socket *sock) session = pppol2tp_sock_to_session(sk); if (session) { - struct pppol2tp_session *ps; - l2tp_session_delete(session); - - ps = l2tp_session_priv(session); - mutex_lock(&ps->sk_lock); - ps->__sk = rcu_dereference_protected(ps->sk, - lockdep_is_held(&ps->sk_lock)); - RCU_INIT_POINTER(ps->sk, NULL); - mutex_unlock(&ps->sk_lock); - call_rcu(&ps->rcu, pppol2tp_put_sk); - - /* Rely on the sock_put() call at the end of the function for - * dropping the reference held by pppol2tp_sock_to_session(). - * The last reference will be dropped by pppol2tp_put_sk(). - */ + /* drop ref taken by pppol2tp_sock_to_session */ + l2tp_session_dec_refcount(session); } release_sock(sk); - /* This will delete the session context via - * pppol2tp_session_destruct() if the socket's refcnt drops to - * zero. - */ sock_put(sk); return 0; @@ -506,6 +487,7 @@ static int pppol2tp_create(struct net *net, struct socket *sock, int kern) goto out; sock_init_data(sock, sk); + sock_set_flag(sk, SOCK_RCU_FREE); sock->state = SS_UNCONNECTED; sock->ops = &pppol2tp_ops; @@ -542,6 +524,7 @@ static void pppol2tp_session_init(struct l2tp_session *session) struct pppol2tp_session *ps; session->recv_skb = pppol2tp_recv; + session->session_close = pppol2tp_session_close; if (IS_ENABLED(CONFIG_L2TP_DEBUGFS)) session->show = pppol2tp_show; @@ -830,12 +813,13 @@ static int pppol2tp_connect(struct socket *sock, struct sockaddr *uservaddr, out_no_ppp: /* This is how we get the session context from the socket. */ - sk->sk_user_data = session; + sock_hold(sk); + rcu_assign_sk_user_data(sk, session); rcu_assign_pointer(ps->sk, sk); mutex_unlock(&ps->sk_lock); /* Keep the reference we've grabbed on the session: sk doesn't expect - * the session to disappear. pppol2tp_session_destruct() is responsible + * the session to disappear. pppol2tp_session_close() is responsible * for dropping it. */ drop_refcnt = false; @@ -1002,7 +986,7 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr, error = len; - sock_put(sk); + l2tp_session_dec_refcount(session); end: return error; } @@ -1274,7 +1258,7 @@ static int pppol2tp_setsockopt(struct socket *sock, int level, int optname, err = pppol2tp_session_setsockopt(sk, session, optname, val); } - sock_put(sk); + l2tp_session_dec_refcount(session); end: return err; } @@ -1395,7 +1379,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname, err = 0; end_put_sess: - sock_put(sk); + l2tp_session_dec_refcount(session); end: return err; } |