From 829a3ada9cc7d4c30fa61f8033403fb6c8f8092a Mon Sep 17 00:00:00 2001 From: Jesse Gross Date: Fri, 2 Jan 2015 18:26:03 -0800 Subject: [PATCH] geneve: Simplify locking. The existing Geneve locking scheme was pulled over directly from VXLAN. However, VXLAN has a number of built in mechanisms which make the locking more complex and are unlikely to be necessary with Geneve. This simplifies the locking to use a basic scheme of a mutex when doing updates plus RCU on receive. In addition to making the code easier to read, this also avoids the possibility of a race when creating or destroying sockets since UDP sockets and the list of Geneve sockets are protected by different locks. After this change, the entire operation is atomic. Signed-off-by: Jesse Gross Signed-off-by: David S. Miller --- include/net/geneve.h | 2 +- net/ipv4/geneve.c | 59 +++++++++++++++++++++++----------------------------- 2 files changed, 27 insertions(+), 34 deletions(-) diff --git a/include/net/geneve.h b/include/net/geneve.h index 56c7e1a..b40f4af 100644 --- a/include/net/geneve.h +++ b/include/net/geneve.h @@ -73,7 +73,7 @@ struct geneve_sock { void *rcv_data; struct socket *sock; struct rcu_head rcu; - atomic_t refcnt; + int refcnt; struct udp_offload udp_offloads; }; diff --git a/net/ipv4/geneve.c b/net/ipv4/geneve.c index 136a829..ad8dbae 100644 --- a/net/ipv4/geneve.c +++ b/net/ipv4/geneve.c @@ -17,7 +17,7 @@ #include #include #include -#include +#include #include #include #include @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -50,13 +51,15 @@ #include #endif +/* Protects sock_list and refcounts. */ +static DEFINE_MUTEX(geneve_mutex); + #define PORT_HASH_BITS 8 #define PORT_HASH_SIZE (1<sock->sk)->inet_sport == port) return gs; } @@ -336,7 +339,6 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port, geneve_rcv_t *rcv, void *data, bool ipv6) { - struct geneve_net *gn = net_generic(net, geneve_net_id); struct geneve_sock *gs; struct socket *sock; struct udp_tunnel_sock_cfg tunnel_cfg; @@ -352,7 +354,7 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port, } gs->sock = sock; - atomic_set(&gs->refcnt, 1); + gs->refcnt = 1; gs->rcv = rcv; gs->rcv_data = data; @@ -360,11 +362,7 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port, gs->udp_offloads.port = port; gs->udp_offloads.callbacks.gro_receive = geneve_gro_receive; gs->udp_offloads.callbacks.gro_complete = geneve_gro_complete; - - spin_lock(&gn->sock_lock); - hlist_add_head_rcu(&gs->hlist, gs_head(net, port)); geneve_notify_add_rx_port(gs); - spin_unlock(&gn->sock_lock); /* Mark socket as an encapsulation socket */ tunnel_cfg.sk_user_data = gs; @@ -373,6 +371,8 @@ static struct geneve_sock *geneve_socket_create(struct net *net, __be16 port, tunnel_cfg.encap_destroy = NULL; setup_udp_tunnel_sock(net, sock, &tunnel_cfg); + hlist_add_head(&gs->hlist, gs_head(net, port)); + return gs; } @@ -380,25 +380,21 @@ struct geneve_sock *geneve_sock_add(struct net *net, __be16 port, geneve_rcv_t *rcv, void *data, bool no_share, bool ipv6) { - struct geneve_net *gn = net_generic(net, geneve_net_id); struct geneve_sock *gs; - gs = geneve_socket_create(net, port, rcv, data, ipv6); - if (!IS_ERR(gs)) - return gs; - - if (no_share) /* Return error if sharing is not allowed. */ - return ERR_PTR(-EINVAL); + mutex_lock(&geneve_mutex); - spin_lock(&gn->sock_lock); gs = geneve_find_sock(net, port); - if (gs && ((gs->rcv != rcv) || - !atomic_add_unless(&gs->refcnt, 1, 0))) + if (gs) { + if (!no_share && gs->rcv == rcv) + gs->refcnt++; + else gs = ERR_PTR(-EBUSY); - spin_unlock(&gn->sock_lock); + } else { + gs = geneve_socket_create(net, port, rcv, data, ipv6); + } - if (!gs) - gs = ERR_PTR(-EINVAL); + mutex_unlock(&geneve_mutex); return gs; } @@ -406,19 +402,18 @@ EXPORT_SYMBOL_GPL(geneve_sock_add); void geneve_sock_release(struct geneve_sock *gs) { - struct net *net = sock_net(gs->sock->sk); - struct geneve_net *gn = net_generic(net, geneve_net_id); + mutex_lock(&geneve_mutex); - if (!atomic_dec_and_test(&gs->refcnt)) - return; + if (--gs->refcnt) + goto unlock; - spin_lock(&gn->sock_lock); - hlist_del_rcu(&gs->hlist); + hlist_del(&gs->hlist); geneve_notify_del_rx_port(gs); - spin_unlock(&gn->sock_lock); - udp_tunnel_sock_release(gs->sock); kfree_rcu(gs, rcu); + +unlock: + mutex_unlock(&geneve_mutex); } EXPORT_SYMBOL_GPL(geneve_sock_release); @@ -427,8 +422,6 @@ static __net_init int geneve_init_net(struct net *net) struct geneve_net *gn = net_generic(net, geneve_net_id); unsigned int h; - spin_lock_init(&gn->sock_lock); - for (h = 0; h < PORT_HASH_SIZE; ++h) INIT_HLIST_HEAD(&gn->sock_list[h]); @@ -454,7 +447,7 @@ static int __init geneve_init_module(void) return 0; } -late_initcall(geneve_init_module); +module_init(geneve_init_module); static void __exit geneve_cleanup_module(void) { -- 2.7.4