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Commit 6c7e7610 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv4: fix a dst leak in tunnels 



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: 7d442fab ("ipv4: Cache dst in tunnels")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Cong Wang <cwang@twopensource.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent db893473

include/net/ip_tunnels.h

+0 −1
Original line number Diff line number Diff line
@@ -40,7 +40,6 @@ struct ip_tunnel_prl_entry { 


struct ip_tunnel_dst {

	struct dst_entry __rcu 		*dst;

	spinlock_t			lock;

};



struct ip_tunnel {

net/ipv4/ip_tunnel.c

+14 −20
Original line number Diff line number Diff line
@@ -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,

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))

	if (dst) {

		if (dst->flags & DST_NOCACHE)

			dst = NULL;



	spin_lock_bh(&idst->lock);

	old_dst = rcu_dereference(idst->dst);

	rcu_assign_pointer(idst->dst, dst);

		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);