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Commit 1507850b authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

gre: get rid of ipgre_lock 



As RTNL is held while doing tunnels inserts and deletes, we can remove
ipgre_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 b7285b79

net/ipv4/ip_gre.c

+32 −29
Original line number Diff line number Diff line
@@ -129,7 +129,7 @@ static int ipgre_tunnel_bind_dev(struct net_device *dev); 


static int ipgre_net_id __read_mostly;

struct ipgre_net {

	struct ip_tunnel *tunnels[4][HASH_SIZE];

	struct ip_tunnel __rcu *tunnels[4][HASH_SIZE];



	struct net_device *fb_tunnel_dev;

};
@@ -159,9 +159,8 @@ struct ipgre_net { 
#define tunnels_l	tunnels[1]

#define tunnels_wc	tunnels[0]

/*

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

 * Locking : hash tables are protected by RCU and RTNL

 */

static DEFINE_SPINLOCK(ipgre_lock);



#define for_each_ip_tunnel_rcu(start) \

	for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
@@ -174,8 +173,8 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
{

	struct net *net = dev_net(dev);

	int link = dev->ifindex;

	unsigned h0 = HASH(remote);

	unsigned h1 = HASH(key);

	unsigned int h0 = HASH(remote);

	unsigned int h1 = HASH(key);

	struct ip_tunnel *t, *cand = NULL;

	struct ipgre_net *ign = net_generic(net, ipgre_net_id);

	int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
@@ -290,13 +289,13 @@ static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 
	return NULL;

}



static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign,

static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign,

		struct ip_tunnel_parm *parms)

{

	__be32 remote = parms->iph.daddr;

	__be32 local = parms->iph.saddr;

	__be32 key = parms->i_key;

	unsigned h = HASH(key);

	unsigned int h = HASH(key);

	int prio = 0;



	if (local)
@@ -309,7 +308,7 @@ static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign, 
	return &ign->tunnels[prio][h];

}



static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign,

static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign,

		struct ip_tunnel *t)

{

	return __ipgre_bucket(ign, &t->parms);
@@ -317,23 +316,22 @@ static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign, 


static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)

{

	struct ip_tunnel **tp = ipgre_bucket(ign, t);

	struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t);



	spin_lock_bh(&ipgre_lock);

	t->next = *tp;

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

	rcu_assign_pointer(*tp, t);

	spin_unlock_bh(&ipgre_lock);

}



static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)

{

	struct ip_tunnel **tp;



	for (tp = ipgre_bucket(ign, t); *tp; tp = &(*tp)->next) {

		if (t == *tp) {

			spin_lock_bh(&ipgre_lock);

			*tp = t->next;

			spin_unlock_bh(&ipgre_lock);

	struct ip_tunnel __rcu **tp;

	struct ip_tunnel *iter;



	for (tp = ipgre_bucket(ign, t);

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

	     tp = &iter->next) {

		if (t == iter) {

			rcu_assign_pointer(*tp, t->next);

			break;

		}

	}
@@ -347,10 +345,13 @@ static struct ip_tunnel *ipgre_tunnel_find(struct net *net, 
	__be32 local = parms->iph.saddr;

	__be32 key = parms->i_key;

	int link = parms->link;

	struct ip_tunnel *t, **tp;

	struct ip_tunnel *t;

	struct ip_tunnel __rcu **tp;

	struct ipgre_net *ign = net_generic(net, ipgre_net_id);



	for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next)

	for (tp = __ipgre_bucket(ign, parms);

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

	     tp = &t->next)

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

		    remote == t->parms.iph.daddr &&

		    key == t->parms.i_key &&
@@ -1013,7 +1014,7 @@ ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) 
					break;

				}

			} else {

				unsigned nflags = 0;

				unsigned int nflags = 0;



				t = netdev_priv(dev);
@@ -1126,7 +1127,7 @@ static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu) 


static int ipgre_header(struct sk_buff *skb, struct net_device *dev,

			unsigned short type,

			const void *daddr, const void *saddr, unsigned len)

			const void *daddr, const void *saddr, unsigned int len)

{

	struct ip_tunnel *t = netdev_priv(dev);

	struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
@@ -1275,7 +1276,7 @@ static void ipgre_fb_tunnel_init(struct net_device *dev) 
	tunnel->hlen		= sizeof(struct iphdr) + 4;



	dev_hold(dev);

	ign->tunnels_wc[0]	= tunnel;

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

}
@@ -1291,11 +1292,13 @@ static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head) 
	for (prio = 0; prio < 4; prio++) {

		int h;

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

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

			struct ip_tunnel *t;



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



			while (t != NULL) {

				unregister_netdevice_queue(t->dev, head);

				t = t->next;

				t = rtnl_dereference(t->next);

			}

		}

	}
@@ -1522,7 +1525,7 @@ static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 
		t = nt;



		if (dev->type != ARPHRD_ETHER) {

			unsigned nflags = 0;

			unsigned int nflags = 0;



			if (ipv4_is_multicast(p.iph.daddr))

				nflags = IFF_BROADCAST;