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l2tp: improve tunnel/session refcount helpers
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l2tp_tunnel_inc_refcount and l2tp_session_inc_refcount wrap
refcount_inc. They add no value so just use the refcount APIs directly
and drop l2tp's helpers. l2tp already uses refcount_inc_not_zero
anyway.

Rename l2tp_tunnel_dec_refcount and l2tp_session_dec_refcount to
l2tp_tunnel_put and l2tp_session_put to better match their use pairing
various _get getters.

Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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James Chapman authored and David S. Miller committed Aug 11, 2024
1 parent 1f4c3dc commit abe7a1a
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Showing 8 changed files with 79 additions and 93 deletions.
52 changes: 20 additions & 32 deletions net/l2tp/l2tp_core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -170,7 +170,7 @@ static void l2tp_session_free(struct l2tp_session *session)
{
trace_free_session(session);
if (session->tunnel)
l2tp_tunnel_dec_refcount(session->tunnel);
l2tp_tunnel_put(session->tunnel);
kfree_rcu(session, rcu);
}

Expand All @@ -197,31 +197,19 @@ struct l2tp_tunnel *l2tp_sk_to_tunnel(const struct sock *sk)
}
EXPORT_SYMBOL_GPL(l2tp_sk_to_tunnel);

void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel)
{
refcount_inc(&tunnel->ref_count);
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_inc_refcount);

void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel)
void l2tp_tunnel_put(struct l2tp_tunnel *tunnel)
{
if (refcount_dec_and_test(&tunnel->ref_count))
l2tp_tunnel_free(tunnel);
}
EXPORT_SYMBOL_GPL(l2tp_tunnel_dec_refcount);

void l2tp_session_inc_refcount(struct l2tp_session *session)
{
refcount_inc(&session->ref_count);
}
EXPORT_SYMBOL_GPL(l2tp_session_inc_refcount);
EXPORT_SYMBOL_GPL(l2tp_tunnel_put);

void l2tp_session_dec_refcount(struct l2tp_session *session)
void l2tp_session_put(struct l2tp_session *session)
{
if (refcount_dec_and_test(&session->ref_count))
l2tp_session_free(session);
}
EXPORT_SYMBOL_GPL(l2tp_session_dec_refcount);
EXPORT_SYMBOL_GPL(l2tp_session_put);

/* Lookup a tunnel. A new reference is held on the returned tunnel. */
struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id)
Expand Down Expand Up @@ -454,7 +442,7 @@ struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
if (tunnel) {
list_for_each_entry_rcu(session, &tunnel->session_list, list) {
if (!strcmp(session->ifname, ifname)) {
l2tp_session_inc_refcount(session);
refcount_inc(&session->ref_count);
rcu_read_unlock_bh();

return session;
Expand All @@ -471,7 +459,7 @@ EXPORT_SYMBOL_GPL(l2tp_session_get_by_ifname);
static void l2tp_session_coll_list_add(struct l2tp_session_coll_list *clist,
struct l2tp_session *session)
{
l2tp_session_inc_refcount(session);
refcount_inc(&session->ref_count);
WARN_ON_ONCE(session->coll_list);
session->coll_list = clist;
spin_lock(&clist->lock);
Expand Down Expand Up @@ -557,7 +545,7 @@ static void l2tp_session_collision_del(struct l2tp_net *pn,
spin_unlock(&clist->lock);
if (refcount_dec_and_test(&clist->ref_count))
kfree(clist);
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
}
}

Expand Down Expand Up @@ -606,7 +594,7 @@ int l2tp_session_register(struct l2tp_session *session,
goto out;
}

l2tp_tunnel_inc_refcount(tunnel);
refcount_inc(&tunnel->ref_count);
WRITE_ONCE(session->tunnel, tunnel);
list_add_rcu(&session->list, &tunnel->session_list);

Expand Down Expand Up @@ -1089,7 +1077,7 @@ int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)

if (!session || !session->recv_skb) {
if (session)
l2tp_session_dec_refcount(session);
l2tp_session_put(session);

/* Not found? Pass to userspace to deal with */
goto pass;
Expand All @@ -1103,12 +1091,12 @@ int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)

if (version == L2TP_HDR_VER_3 &&
l2tp_v3_ensure_opt_in_linear(session, skb, &ptr, &optr)) {
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
goto invalid;
}

l2tp_recv_common(session, skb, ptr, optr, hdrflags, length);
l2tp_session_dec_refcount(session);
l2tp_session_put(session);

return 0;

Expand Down Expand Up @@ -1408,7 +1396,7 @@ static void l2tp_udp_encap_destroy(struct sock *sk)
tunnel = l2tp_sk_to_tunnel(sk);
if (tunnel) {
l2tp_tunnel_delete(tunnel);
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);
}
}

Expand Down Expand Up @@ -1443,10 +1431,10 @@ static void l2tp_tunnel_del_work(struct work_struct *work)

l2tp_tunnel_remove(tunnel->l2tp_net, tunnel);
/* drop initial ref */
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);

/* drop workqueue ref */
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);
}

/* Create a socket for the tunnel, if one isn't set up by
Expand Down Expand Up @@ -1634,7 +1622,7 @@ static int l2tp_validate_socket(const struct sock *sk, const struct net *net,

tunnel = l2tp_sk_to_tunnel(sk);
if (tunnel) {
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);
return -EBUSY;
}

Expand Down Expand Up @@ -1726,7 +1714,7 @@ void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel)
{
if (!test_and_set_bit(0, &tunnel->dead)) {
trace_delete_tunnel(tunnel);
l2tp_tunnel_inc_refcount(tunnel);
refcount_inc(&tunnel->ref_count);
queue_work(l2tp_wq, &tunnel->del_work);
}
}
Expand All @@ -1736,7 +1724,7 @@ void l2tp_session_delete(struct l2tp_session *session)
{
if (!test_and_set_bit(0, &session->dead)) {
trace_delete_session(session);
l2tp_session_inc_refcount(session);
refcount_inc(&session->ref_count);
queue_work(l2tp_wq, &session->del_work);
}
}
Expand All @@ -1754,10 +1742,10 @@ static void l2tp_session_del_work(struct work_struct *work)
(*session->session_close)(session);

/* drop initial ref */
l2tp_session_dec_refcount(session);
l2tp_session_put(session);

/* drop workqueue ref */
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
}

/* We come here whenever a session's send_seq, cookie_len or
Expand Down
6 changes: 2 additions & 4 deletions net/l2tp/l2tp_core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -209,10 +209,8 @@ static inline void *l2tp_session_priv(struct l2tp_session *session)
}

/* Tunnel and session refcounts */
void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel);
void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel);
void l2tp_session_inc_refcount(struct l2tp_session *session);
void l2tp_session_dec_refcount(struct l2tp_session *session);
void l2tp_tunnel_put(struct l2tp_tunnel *tunnel);
void l2tp_session_put(struct l2tp_session *session);

/* Tunnel and session lookup.
* These functions take a reference on the instances they return, so
Expand Down
8 changes: 4 additions & 4 deletions net/l2tp/l2tp_debugfs.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ static void l2tp_dfs_next_tunnel(struct l2tp_dfs_seq_data *pd)
{
/* Drop reference taken during previous invocation */
if (pd->tunnel)
l2tp_tunnel_dec_refcount(pd->tunnel);
l2tp_tunnel_put(pd->tunnel);

pd->tunnel = l2tp_tunnel_get_next(pd->net, &pd->tkey);
pd->tkey++;
Expand All @@ -54,7 +54,7 @@ static void l2tp_dfs_next_session(struct l2tp_dfs_seq_data *pd)
{
/* Drop reference taken during previous invocation */
if (pd->session)
l2tp_session_dec_refcount(pd->session);
l2tp_session_put(pd->session);

pd->session = l2tp_session_get_next(pd->net, pd->tunnel->sock,
pd->tunnel->version,
Expand Down Expand Up @@ -111,11 +111,11 @@ static void l2tp_dfs_seq_stop(struct seq_file *p, void *v)
* or l2tp_dfs_next_tunnel().
*/
if (pd->session) {
l2tp_session_dec_refcount(pd->session);
l2tp_session_put(pd->session);
pd->session = NULL;
}
if (pd->tunnel) {
l2tp_tunnel_dec_refcount(pd->tunnel);
l2tp_tunnel_put(pd->tunnel);
pd->tunnel = NULL;
}
}
Expand Down
10 changes: 5 additions & 5 deletions net/l2tp/l2tp_eth.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -283,7 +283,7 @@ static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,

spriv = l2tp_session_priv(session);

l2tp_session_inc_refcount(session);
refcount_inc(&session->ref_count);

rtnl_lock();

Expand All @@ -301,7 +301,7 @@ static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,
if (rc < 0) {
rtnl_unlock();
l2tp_session_delete(session);
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
free_netdev(dev);

return rc;
Expand All @@ -312,17 +312,17 @@ static int l2tp_eth_create(struct net *net, struct l2tp_tunnel *tunnel,

rtnl_unlock();

l2tp_session_dec_refcount(session);
l2tp_session_put(session);

__module_get(THIS_MODULE);

return 0;

err_sess_dev:
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
free_netdev(dev);
err_sess:
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
err:
return rc;
}
Expand Down
6 changes: 3 additions & 3 deletions net/l2tp/l2tp_ip.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ static int l2tp_ip_recv(struct sk_buff *skb)
goto discard_sess;

l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
l2tp_session_dec_refcount(session);
l2tp_session_put(session);

return 0;

Expand Down Expand Up @@ -200,7 +200,7 @@ static int l2tp_ip_recv(struct sk_buff *skb)
return sk_receive_skb(sk, skb, 1);

discard_sess:
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
goto discard;

discard_put:
Expand Down Expand Up @@ -265,7 +265,7 @@ static void l2tp_ip_destroy_sock(struct sock *sk)
tunnel = l2tp_sk_to_tunnel(sk);
if (tunnel) {
l2tp_tunnel_delete(tunnel);
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);
}
}

Expand Down
6 changes: 3 additions & 3 deletions net/l2tp/l2tp_ip6.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,7 @@ static int l2tp_ip6_recv(struct sk_buff *skb)
goto discard_sess;

l2tp_recv_common(session, skb, ptr, optr, 0, skb->len);
l2tp_session_dec_refcount(session);
l2tp_session_put(session);

return 0;

Expand Down Expand Up @@ -210,7 +210,7 @@ static int l2tp_ip6_recv(struct sk_buff *skb)
return sk_receive_skb(sk, skb, 1);

discard_sess:
l2tp_session_dec_refcount(session);
l2tp_session_put(session);
goto discard;

discard_put:
Expand Down Expand Up @@ -276,7 +276,7 @@ static void l2tp_ip6_destroy_sock(struct sock *sk)
tunnel = l2tp_sk_to_tunnel(sk);
if (tunnel) {
l2tp_tunnel_delete(tunnel);
l2tp_tunnel_dec_refcount(tunnel);
l2tp_tunnel_put(tunnel);
}
}

Expand Down
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