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Date: Fri, 9 Feb 2018 15:00:22 +0000
From: James Chapman <jchapman@...alix.com>
To: netdev@...r.kernel.org
Subject: [PATCH net-next 06/16] l2tp: refactor session lifetime handling
Simplify relationship with tunnel such that the session holds a ref on
the tunnel, not its socket. This guarantees that the tunnel is always
extant if one or more sessions exists on the tunnel. If the session
has a socket (ppp), have it hold a ref on the socket until the session
is destroyed.
Since pppol2tp_sock_to_session returns a session and the session now
holds a sock ref, have it return with a ref on the session.
Fixes: fd558d186df2c ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Fixes: f3c66d4e144a0 ("l2tp: prevent creation of sessions on terminated tunnels")
Signed-off-by: James Chapman <jchapman@...alix.com>
---
net/l2tp/l2tp_core.c | 7 ++-----
net/l2tp/l2tp_ppp.c | 36 ++++++++++++++++++------------------
2 files changed, 20 insertions(+), 23 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 691fe9368d91..477b96cf8ab3 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -290,6 +290,7 @@ int l2tp_session_register(struct l2tp_session *session,
spin_unlock_bh(&tunnel->lock);
return -ENODEV;
}
+ l2tp_tunnel_inc_refcount(tunnel);
spin_unlock_bh(&tunnel->lock);
head = l2tp_session_id_hash(tunnel, session->session_id);
@@ -315,14 +316,9 @@ int l2tp_session_register(struct l2tp_session *session,
goto err_tlock_pnlock;
}
- l2tp_tunnel_inc_refcount(tunnel);
- sock_hold(tunnel->sock);
hlist_add_head_rcu(&session->global_hlist, g_head);
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
- } else {
- l2tp_tunnel_inc_refcount(tunnel);
- sock_hold(tunnel->sock);
}
hlist_add_head(&session->hlist, head);
@@ -334,6 +330,7 @@ int l2tp_session_register(struct l2tp_session *session,
spin_unlock_bh(&pn->l2tp_session_hlist_lock);
err_tlock:
write_unlock_bh(&tunnel->hlist_lock);
+ l2tp_tunnel_dec_refcount(tunnel);
return err;
}
diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index fe5a0043dd32..ff95a4d4eac5 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -166,16 +166,17 @@ static inline struct l2tp_session *pppol2tp_sock_to_session(struct sock *sk)
if (sk == NULL)
return NULL;
- sock_hold(sk);
- session = (struct l2tp_session *)(sk->sk_user_data);
+ rcu_read_lock_bh();
+ session = rcu_dereference_bh(__sk_user_data((sk)));
if (session == NULL) {
- sock_put(sk);
- goto out;
+ rcu_read_unlock_bh();
+ return NULL;
}
+ l2tp_session_inc_refcount(session);
+ rcu_read_unlock();
BUG_ON(session->magic != L2TP_SESSION_MAGIC);
-out:
return session;
}
@@ -243,8 +244,8 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int
/* If the socket is bound, send it in to PPP's input queue. Otherwise
* queue it on the session socket.
*/
- rcu_read_lock();
- sk = rcu_dereference(ps->sk);
+ rcu_read_lock_bh();
+ sk = rcu_dereference_bh(ps->sk);
if (sk == NULL)
goto no_sock;
@@ -267,12 +268,12 @@ static void pppol2tp_recv(struct l2tp_session *session, struct sk_buff *skb, int
kfree_skb(skb);
}
}
- rcu_read_unlock();
+ rcu_read_unlock_bh();
return;
no_sock:
- rcu_read_unlock();
+ rcu_read_unlock_bh();
l2tp_info(session, L2TP_MSG_DATA, "%s: no socket\n", session->name);
kfree_skb(skb);
}
@@ -341,12 +342,12 @@ static int pppol2tp_sendmsg(struct socket *sock, struct msghdr *m,
l2tp_xmit_skb(session, skb, session->hdr_len);
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;
}
@@ -400,12 +401,12 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
l2tp_xmit_skb(session, skb, session->hdr_len);
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);
@@ -483,7 +484,6 @@ static int pppol2tp_release(struct socket *sock)
sock->sk = NULL;
session = pppol2tp_sock_to_session(sk);
-
if (session != NULL) {
struct pppol2tp_session *ps;
@@ -976,7 +976,7 @@ static int pppol2tp_getname(struct socket *sock, struct sockaddr *uaddr,
*usockaddr_len = len;
error = 0;
- sock_put(sk);
+ l2tp_session_dec_refcount(session);
end:
return error;
}
@@ -1247,7 +1247,7 @@ static int pppol2tp_ioctl(struct socket *sock, unsigned int cmd,
err = pppol2tp_session_ioctl(session, cmd, arg);
end_put_sess:
- sock_put(sk);
+ l2tp_session_dec_refcount(session);
end:
return err;
}
@@ -1398,7 +1398,7 @@ 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;
}
@@ -1530,7 +1530,7 @@ 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;
}
--
1.9.1
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