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Commit b7285b79 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipip: get rid of ipip_lock 



As RTNL is held while doing tunnels inserts and deletes, we can remove
ipip_lock spinlock. My initial RCU conversion was conservative and
converted the rwlock to spinlock, with no RTNL requirement.

Use appropriate rcu annotations and modern lockdep checks as well.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7dff59ef

net/ipv4/ipip.c

+34 −33
Original line number Diff line number Diff line
@@ -122,11 +122,11 @@ 


static int ipip_net_id __read_mostly;

struct ipip_net {

	struct ip_tunnel *tunnels_r_l[HASH_SIZE];

	struct ip_tunnel *tunnels_r[HASH_SIZE];

	struct ip_tunnel *tunnels_l[HASH_SIZE];

	struct ip_tunnel *tunnels_wc[1];

	struct ip_tunnel **tunnels[4];

	struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];

	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];

	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];

	struct ip_tunnel __rcu *tunnels_wc[1];

	struct ip_tunnel __rcu **tunnels[4];



	struct net_device *fb_tunnel_dev;

};
@@ -135,9 +135,8 @@ static void ipip_tunnel_init(struct net_device *dev); 
static void ipip_tunnel_setup(struct net_device *dev);



/*

 * Locking : hash tables are protected by RCU and a spinlock

 * Locking : hash tables are protected by RCU and RTNL

 */

static DEFINE_SPINLOCK(ipip_lock);



#define for_each_ip_tunnel_rcu(start) \

	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
@@ -145,8 +144,8 @@ static DEFINE_SPINLOCK(ipip_lock); 
static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,

		__be32 remote, __be32 local)

{

	unsigned h0 = HASH(remote);

	unsigned h1 = HASH(local);

	unsigned int h0 = HASH(remote);

	unsigned int h1 = HASH(local);

	struct ip_tunnel *t;

	struct ipip_net *ipn = net_generic(net, ipip_net_id);
@@ -169,12 +168,12 @@ static struct ip_tunnel * ipip_tunnel_lookup(struct net *net, 
	return NULL;

}



static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn,

static struct ip_tunnel __rcu **__ipip_bucket(struct ipip_net *ipn,

		struct ip_tunnel_parm *parms)

{

	__be32 remote = parms->iph.daddr;

	__be32 local = parms->iph.saddr;

	unsigned h = 0;

	unsigned int h = 0;

	int prio = 0;



	if (remote) {
@@ -188,7 +187,7 @@ static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn, 
	return &ipn->tunnels[prio][h];

}



static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn,

static inline struct ip_tunnel __rcu **ipip_bucket(struct ipip_net *ipn,

		struct ip_tunnel *t)

{

	return __ipip_bucket(ipn, &t->parms);
@@ -196,13 +195,14 @@ static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn, 


static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)

{

	struct ip_tunnel **tp;



	for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {

		if (t == *tp) {

			spin_lock_bh(&ipip_lock);

			*tp = t->next;

			spin_unlock_bh(&ipip_lock);

	struct ip_tunnel __rcu **tp;

	struct ip_tunnel *iter;



	for (tp = ipip_bucket(ipn, t);

	     (iter = rtnl_dereference(*tp)) != NULL;

	     tp = &iter->next) {

		if (t == iter) {

			rcu_assign_pointer(*tp, t->next);

			break;

		}

	}
@@ -210,12 +210,10 @@ static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t) 


static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)

{

	struct ip_tunnel **tp = ipip_bucket(ipn, t);

	struct ip_tunnel __rcu **tp = ipip_bucket(ipn, t);



	spin_lock_bh(&ipip_lock);

	t->next = *tp;

	rcu_assign_pointer(t->next, rtnl_dereference(*tp));

	rcu_assign_pointer(*tp, t);

	spin_unlock_bh(&ipip_lock);

}



static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
@@ -223,12 +221,15 @@ static struct ip_tunnel * ipip_tunnel_locate(struct net *net, 
{

	__be32 remote = parms->iph.daddr;

	__be32 local = parms->iph.saddr;

	struct ip_tunnel *t, **tp, *nt;

	struct ip_tunnel *t, *nt;

	struct ip_tunnel __rcu **tp;

	struct net_device *dev;

	char name[IFNAMSIZ];

	struct ipip_net *ipn = net_generic(net, ipip_net_id);



	for (tp = __ipip_bucket(ipn, parms); (t = *tp) != NULL; tp = &t->next) {

	for (tp = __ipip_bucket(ipn, parms);

		 (t = rtnl_dereference(*tp)) != NULL;

		 tp = &t->next) {

		if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)

			return t;

	}
@@ -268,16 +269,15 @@ static struct ip_tunnel * ipip_tunnel_locate(struct net *net, 
	return NULL;

}



/* called with RTNL */

static void ipip_tunnel_uninit(struct net_device *dev)

{

	struct net *net = dev_net(dev);

	struct ipip_net *ipn = net_generic(net, ipip_net_id);



	if (dev == ipn->fb_tunnel_dev) {

		spin_lock_bh(&ipip_lock);

		ipn->tunnels_wc[0] = NULL;

		spin_unlock_bh(&ipip_lock);

	} else

	if (dev == ipn->fb_tunnel_dev)

		rcu_assign_pointer(ipn->tunnels_wc[0], NULL);

	else

		ipip_tunnel_unlink(ipn, netdev_priv(dev));

	dev_put(dev);

}
@@ -741,7 +741,7 @@ static void __net_init ipip_fb_tunnel_init(struct net_device *dev) 
	iph->ihl		= 5;



	dev_hold(dev);

	ipn->tunnels_wc[0]	= tunnel;

	rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);

}



static struct xfrm_tunnel ipip_handler __read_mostly = {
@@ -760,11 +760,12 @@ static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head) 
	for (prio = 1; prio < 4; prio++) {

		int h;

		for (h = 0; h < HASH_SIZE; h++) {

			struct ip_tunnel *t = ipn->tunnels[prio][h];

			struct ip_tunnel *t;



			t = rtnl_dereference(ipn->tunnels[prio][h]);

			while (t != NULL) {

				unregister_netdevice_queue(t->dev, head);

				t = t->next;

				t = rtnl_dereference(t->next);

			}

		}

	}