diff --git a/drivers/net/ovpn/netlink.c b/drivers/net/ovpn/netlink.c index 4dad85294198..8cdf46b61142 100644 --- a/drivers/net/ovpn/netlink.c +++ b/drivers/net/ovpn/netlink.c @@ -463,11 +463,11 @@ int ovpn_nl_peer_new_doit(struct sk_buff *skb, struct genl_info *info) ovpn_socket_release(peer); peer_release: /* For UDP, the peer is unreachable until added to the hashtables, so - * dropping the initial reference is enough. For TCP, the peer may be + * killing the initial reference is enough. For TCP, the peer may be * concurrently reachable via sk_user_data->peer until - * ovpn_socket_release() detaches; rely on the refcount. + * ovpn_socket_release() detaches; rely on the percpu reference. */ - ovpn_peer_put(peer); + ovpn_peer_kill(peer); return ret; } diff --git a/drivers/net/ovpn/peer.c b/drivers/net/ovpn/peer.c index c95656ca7c35..3efc3e5c07e2 100644 --- a/drivers/net/ovpn/peer.c +++ b/drivers/net/ovpn/peer.c @@ -33,7 +33,7 @@ static void unlock_ovpn(struct ovpn_priv *ovpn, llist_for_each_entry_safe(peer, next, release_list->first, release_entry) { ovpn_socket_release(peer); - ovpn_peer_put(peer); + ovpn_peer_kill(peer); } } @@ -113,7 +113,6 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn, u32 id) RCU_INIT_POINTER(peer->bind, NULL); ovpn_crypto_state_init(&peer->crypto); spin_lock_init(&peer->lock); - kref_init(&peer->refcount); ovpn_peer_stats_init(&peer->vpn_stats); ovpn_peer_stats_init(&peer->link_stats); INIT_WORK(&peer->keepalive_work, ovpn_peer_keepalive_send); @@ -127,6 +126,14 @@ struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn, u32 id) return ERR_PTR(ret); } + ret = percpu_ref_init(&peer->refcount, ovpn_peer_release_ref, 0, + GFP_KERNEL); + if (ret < 0) { + dst_cache_destroy(&peer->dst_cache); + kfree(peer); + return ERR_PTR(ret); + } + netdev_hold(ovpn->dev, &peer->dev_tracker, GFP_KERNEL); return peer; @@ -348,6 +355,7 @@ static void ovpn_peer_release_rcu(struct rcu_head *head) * perform it in the RCU callback, when all contexts are done */ dst_cache_destroy(&peer->dst_cache); + percpu_ref_exit(&peer->refcount); kfree(peer); } @@ -366,12 +374,12 @@ static void ovpn_peer_release(struct ovpn_peer *peer) } /** - * ovpn_peer_release_kref - callback for kref_put - * @kref: the kref object belonging to the peer + * ovpn_peer_release_ref - callback for the peer percpu reference + * @ref: the percpu_ref object belonging to the peer */ -void ovpn_peer_release_kref(struct kref *kref) +void ovpn_peer_release_ref(struct percpu_ref *ref) { - struct ovpn_peer *peer = container_of(kref, struct ovpn_peer, refcount); + struct ovpn_peer *peer = container_of(ref, struct ovpn_peer, refcount); ovpn_peer_release(peer); } @@ -569,7 +577,7 @@ ovpn_peer_get_by_transp_addr_p2p(struct ovpn_priv *ovpn, rcu_read_lock(); tmp = rcu_dereference(ovpn->peer); if (likely(tmp && ovpn_peer_transp_match(tmp, ss) && - ovpn_peer_hold(tmp))) + ovpn_peer_hold_rcu(tmp))) peer = tmp; rcu_read_unlock(); @@ -610,7 +618,7 @@ struct ovpn_peer *ovpn_peer_get_by_transp_addr(struct ovpn_priv *ovpn, if (!ovpn_peer_transp_match(tmp, &ss)) continue; - if (!ovpn_peer_hold(tmp)) + if (!ovpn_peer_hold_rcu(tmp)) continue; peer = tmp; @@ -641,7 +649,7 @@ static struct ovpn_peer *ovpn_peer_get_by_id_p2p(struct ovpn_priv *ovpn, rcu_read_lock(); tmp = rcu_dereference(ovpn->peer); - if (likely(tmp && tmp->id == peer_id && ovpn_peer_hold(tmp))) + if (likely(tmp && tmp->id == peer_id && ovpn_peer_hold_rcu(tmp))) peer = tmp; rcu_read_unlock(); @@ -671,7 +679,7 @@ struct ovpn_peer *ovpn_peer_get_by_id(struct ovpn_priv *ovpn, u32 peer_id) if (tmp->id != peer_id) continue; - if (!ovpn_peer_hold(tmp)) + if (!ovpn_peer_hold_rcu(tmp)) continue; peer = tmp; @@ -745,7 +753,7 @@ struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_priv *ovpn, if (ovpn->mode == OVPN_MODE_P2P) { rcu_read_lock(); peer = rcu_dereference(ovpn->peer); - if (unlikely(peer && !ovpn_peer_hold(peer))) + if (unlikely(peer && !ovpn_peer_hold_rcu(peer))) peer = NULL; rcu_read_unlock(); return peer; @@ -763,7 +771,7 @@ struct ovpn_peer *ovpn_peer_get_by_dst(struct ovpn_priv *ovpn, break; } - if (unlikely(peer && !ovpn_peer_hold(peer))) + if (unlikely(peer && !ovpn_peer_hold_rcu(peer))) peer = NULL; rcu_read_unlock(); diff --git a/drivers/net/ovpn/peer.h b/drivers/net/ovpn/peer.h index dfa5c0037e02..dd6127976ac9 100644 --- a/drivers/net/ovpn/peer.h +++ b/drivers/net/ovpn/peer.h @@ -10,6 +10,7 @@ #ifndef _NET_OVPN_OVPNPEER_H_ #define _NET_OVPN_OVPNPEER_H_ +#include #include #include @@ -110,7 +111,7 @@ struct ovpn_peer { struct ovpn_peer_stats link_stats; enum ovpn_del_peer_reason delete_reason; spinlock_t lock; /* protects bind and keepalive* */ - struct kref refcount; + struct percpu_ref refcount; struct rcu_head rcu; struct llist_node release_entry; struct work_struct keepalive_work; @@ -124,10 +125,23 @@ struct ovpn_peer { */ static inline bool ovpn_peer_hold(struct ovpn_peer *peer) { - return kref_get_unless_zero(&peer->refcount); + return percpu_ref_tryget_live(&peer->refcount); } -void ovpn_peer_release_kref(struct kref *kref); +/** + * ovpn_peer_hold_rcu - acquire a live peer reference under RCU + * @peer: peer to acquire + * + * The caller must hold rcu_read_lock. + * + * Return: true if the reference was acquired, false if teardown has started + */ +static inline bool ovpn_peer_hold_rcu(struct ovpn_peer *peer) +{ + return percpu_ref_tryget_live_rcu(&peer->refcount); +} + +void ovpn_peer_release_ref(struct percpu_ref *ref); /** * ovpn_peer_put - decrease reference counter @@ -135,7 +149,19 @@ void ovpn_peer_release_kref(struct kref *kref); */ static inline void ovpn_peer_put(struct ovpn_peer *peer) { - kref_put(&peer->refcount, ovpn_peer_release_kref); + percpu_ref_put(&peer->refcount); +} + +/** + * ovpn_peer_kill - drop the peer's initial reference + * @peer: peer which has been unpublished and is being destroyed + * + * This must be called exactly once, after the peer is no longer reachable + * through its owning ovpn instance. + */ +static inline void ovpn_peer_kill(struct ovpn_peer *peer) +{ + percpu_ref_kill(&peer->refcount); } struct ovpn_peer *ovpn_peer_new(struct ovpn_priv *ovpn, u32 id);