From 6c7e7610ff6888ea15a901fbcb30c5d461816b34 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 16 Jan 2014 16:41:19 -0800 Subject: [PATCH] ipv4: fix a dst leak in tunnels MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch : 1) Remove a dst leak if DST_NOCACHE was set on dst Fix this by holding a reference only if dst really cached. 2) Remove a lockdep warning in __tunnel_dst_set() This was reported by Cong Wang. 3) Remove usage of a spinlock where xchg() is enough 4) Remove some spurious inline keywords. Let compiler decide for us. Fixes: 7d442fab0a67 ("ipv4: Cache dst in tunnels") Signed-off-by: Eric Dumazet Cc: Cong Wang Cc: Tom Herbert Cc: Maciej Żenczykowski Signed-off-by: David S. Miller --- include/net/ip_tunnels.h | 1 - net/ipv4/ip_tunnel.c | 34 ++++++++++++++-------------------- 2 files changed, 14 insertions(+), 21 deletions(-) diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h index cd729be..48ed75c 100644 --- a/include/net/ip_tunnels.h +++ b/include/net/ip_tunnels.h @@ -40,7 +40,6 @@ struct ip_tunnel_prl_entry { struct ip_tunnel_dst { struct dst_entry __rcu *dst; - spinlock_t lock; }; struct ip_tunnel { diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index d3929a6..432c28a 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -68,27 +68,27 @@ static unsigned int ip_tunnel_hash(struct ip_tunnel_net *itn, IP_TNL_HASH_BITS); } -static inline void __tunnel_dst_set(struct ip_tunnel_dst *idst, - struct dst_entry *dst) +static void __tunnel_dst_set(struct ip_tunnel_dst *idst, + struct dst_entry *dst) { struct dst_entry *old_dst; - if (dst && (dst->flags & DST_NOCACHE)) - dst = NULL; - - spin_lock_bh(&idst->lock); - old_dst = rcu_dereference(idst->dst); - rcu_assign_pointer(idst->dst, dst); + if (dst) { + if (dst->flags & DST_NOCACHE) + dst = NULL; + else + dst_clone(dst); + } + old_dst = xchg((__force struct dst_entry **)&idst->dst, dst); dst_release(old_dst); - spin_unlock_bh(&idst->lock); } -static inline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst) +static void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst) { __tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst); } -static inline void tunnel_dst_reset(struct ip_tunnel *t) +static void tunnel_dst_reset(struct ip_tunnel *t) { tunnel_dst_set(t, NULL); } @@ -101,7 +101,7 @@ static void tunnel_dst_reset_all(struct ip_tunnel *t) __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL); } -static inline struct dst_entry *tunnel_dst_get(struct ip_tunnel *t) +static struct dst_entry *tunnel_dst_get(struct ip_tunnel *t) { struct dst_entry *dst; @@ -413,7 +413,7 @@ static int ip_tunnel_bind_dev(struct net_device *dev) if (!IS_ERR(rt)) { tdev = rt->dst.dev; - tunnel_dst_set(tunnel, dst_clone(&rt->dst)); + tunnel_dst_set(tunnel, &rt->dst); ip_rt_put(rt); } if (dev->type != ARPHRD_ETHER) @@ -668,7 +668,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, goto tx_error; } if (connected) - tunnel_dst_set(tunnel, dst_clone(&rt->dst)); + tunnel_dst_set(tunnel, &rt->dst); } if (rt->dst.dev == dev) { @@ -1066,12 +1066,6 @@ int ip_tunnel_init(struct net_device *dev) return -ENOMEM; } - for_each_possible_cpu(i) { - struct ip_tunnel_dst *idst = per_cpu_ptr(tunnel->dst_cache, i); - idst-> dst = NULL; - spin_lock_init(&idst->lock); - } - err = gro_cells_init(&tunnel->gro_cells, dev); if (err) { free_percpu(tunnel->dst_cache); -- 2.7.4