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Commit a43912ab authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tunnel: eliminate recursion field 



It seems recursion field from "struct ip_tunnel" is not anymore needed.
recursion prevention is done at the upper level (in dev_queue_xmit()),
since we use HARD_TX_LOCK protection for tunnels.

This avoids a cache line ping pong on "struct ip_tunnel" : This structure
should be now mostly read on xmit and receive paths.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent edf42a27

include/net/ipip.h

+0 −1
Original line number Diff line number Diff line
@@ -12,7 +12,6 @@ struct ip_tunnel 
	struct ip_tunnel	*next;

	struct net_device	*dev;



	int			recursion;	/* Depth of hard_start_xmit recursion */

	int			err_count;	/* Number of arrived ICMP errors */

	unsigned long		err_time;	/* Time when the last ICMP error arrived */

net/ipv4/ip_gre.c

+1 −12
Original line number Diff line number Diff line
@@ -66,10 +66,7 @@ 
   solution, but it supposes maintaing new variable in ALL

   skb, even if no tunneling is used.



   Current solution: t->recursion lock breaks dead loops. It looks

   like dev->tbusy flag, but I preferred new variable, because

   the semantics is different. One day, when hard_start_xmit

   will be multithreaded we will have to use skb->encapsulation.

   Current solution: HARD_TX_LOCK lock breaks dead loops.
@@ -678,11 +675,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev 
	__be32 dst;

	int    mtu;



	if (tunnel->recursion++) {

		stats->collisions++;

		goto tx_error;

	}



	if (dev->type == ARPHRD_ETHER)

		IPCB(skb)->flags = 0;
@@ -820,7 +812,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev 
			ip_rt_put(rt);

			stats->tx_dropped++;

			dev_kfree_skb(skb);

			tunnel->recursion--;

			return NETDEV_TX_OK;

		}

		if (skb->sk)
@@ -888,7 +879,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev 
	nf_reset(skb);



	IPTUNNEL_XMIT();

	tunnel->recursion--;

	return NETDEV_TX_OK;



tx_error_icmp:
@@ -897,7 +887,6 @@ tx_error_icmp: 
tx_error:

	stats->tx_errors++;

	dev_kfree_skb(skb);

	tunnel->recursion--;

	return NETDEV_TX_OK;

}

net/ipv4/ipip.c

+0 −8
Original line number Diff line number Diff line
@@ -402,11 +402,6 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 
	__be32 dst = tiph->daddr;

	int    mtu;



	if (tunnel->recursion++) {

		stats->collisions++;

		goto tx_error;

	}



	if (skb->protocol != htons(ETH_P_IP))

		goto tx_error;
@@ -485,7 +480,6 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 
			ip_rt_put(rt);

			stats->tx_dropped++;

			dev_kfree_skb(skb);

			tunnel->recursion--;

			return NETDEV_TX_OK;

		}

		if (skb->sk)
@@ -523,7 +517,6 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 
	nf_reset(skb);



	IPTUNNEL_XMIT();

	tunnel->recursion--;

	return NETDEV_TX_OK;



tx_error_icmp:
@@ -531,7 +524,6 @@ tx_error_icmp: 
tx_error:

	stats->tx_errors++;

	dev_kfree_skb(skb);

	tunnel->recursion--;

	return NETDEV_TX_OK;

}

net/ipv6/ip6_tunnel.c

+0 −7
Original line number Diff line number Diff line
@@ -1043,11 +1043,6 @@ ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	struct net_device_stats *stats = &t->dev->stats;

	int ret;



	if (t->recursion++) {

		stats->collisions++;

		goto tx_err;

	}



	switch (skb->protocol) {

	case htons(ETH_P_IP):

		ret = ip4ip6_tnl_xmit(skb, dev);
@@ -1062,14 +1057,12 @@ ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (ret < 0)

		goto tx_err;



	t->recursion--;

	return NETDEV_TX_OK;



tx_err:

	stats->tx_errors++;

	stats->tx_dropped++;

	kfree_skb(skb);

	t->recursion--;

	return NETDEV_TX_OK;

}

net/ipv6/sit.c

+0 −8
Original line number Diff line number Diff line
@@ -626,11 +626,6 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, 
	struct in6_addr *addr6;

	int addr_type;



	if (tunnel->recursion++) {

		stats->collisions++;

		goto tx_error;

	}



	if (skb->protocol != htons(ETH_P_IPV6))

		goto tx_error;
@@ -753,7 +748,6 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, 
			ip_rt_put(rt);

			stats->tx_dropped++;

			dev_kfree_skb(skb);

			tunnel->recursion--;

			return NETDEV_TX_OK;

		}

		if (skb->sk)
@@ -794,7 +788,6 @@ static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb, 
	nf_reset(skb);



	IPTUNNEL_XMIT();

	tunnel->recursion--;

	return NETDEV_TX_OK;



tx_error_icmp:
@@ -802,7 +795,6 @@ tx_error_icmp: 
tx_error:

	stats->tx_errors++;

	dev_kfree_skb(skb);

	tunnel->recursion--;

	return NETDEV_TX_OK;

}