[1/5] inet: Hide route peer accesses behind helpers.

diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index b84b32f..d432489 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -71,6 +71,60 @@  struct inet_peer_base {
 	int			total;
 };
 
+#define INETPEER_BASE_BIT	0x1UL
+
+static inline struct inet_peer *inetpeer_ptr(unsigned long val)
+{
+	BUG_ON(val & INETPEER_BASE_BIT);
+	return (struct inet_peer *) val;
+}
+
+static inline struct inet_peer_base *inetpeer_base_ptr(unsigned long val)
+{
+	if (!(val & INETPEER_BASE_BIT))
+		return NULL;
+	val &= ~INETPEER_BASE_BIT;
+	return (struct inet_peer_base *) val;
+}
+
+static inline bool inetpeer_ptr_is_peer(unsigned long val)
+{
+	return !(val & INETPEER_BASE_BIT);
+}
+
+static inline void __inetpeer_ptr_set_peer(unsigned long *val, struct inet_peer *peer)
+{
+	/* This implicitly clears INETPEER_BASE_BIT */
+	*val = (unsigned long) peer;
+}
+
+static inline bool inetpeer_ptr_set_peer(unsigned long *ptr, struct inet_peer *peer)
+{
+	unsigned long val = (unsigned long) peer;
+	unsigned long orig = *ptr;
+
+	if (!(orig & INETPEER_BASE_BIT) || !val ||
+	    cmpxchg(ptr, orig, val) != orig)
+		return false;
+	return true;
+}
+
+static inline void inetpeer_init_ptr(unsigned long *ptr, struct inet_peer_base *base)
+{
+	*ptr = (unsigned long) base | INETPEER_BASE_BIT;
+}
+
+static inline void inetpeer_transfer_peer(unsigned long *to, unsigned long *from)
+{
+	unsigned long val = *from;
+
+	*to = val;
+	if (inetpeer_ptr_is_peer(val)) {
+		struct inet_peer *peer = inetpeer_ptr(val);
+		atomic_inc(&peer->refcnt);
+	}
+}
+
 extern void inet_peer_base_init(struct inet_peer_base *);
 
 void			inet_initpeers(void) __init;
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 0ae759a..3ac5f15 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -107,7 +107,7 @@  struct rt6_info {
 	u32				rt6i_peer_genid;
 
 	struct inet6_dev		*rt6i_idev;
-	struct inet_peer		*rt6i_peer;
+	unsigned long			_rt6i_peer;
 
 #ifdef CONFIG_XFRM
 	u32				rt6i_flow_cache_genid;
@@ -118,6 +118,36 @@  struct rt6_info {
 	u8				rt6i_protocol;
 };
 
+static inline struct inet_peer *rt6_peer_ptr(struct rt6_info *rt)
+{
+	return inetpeer_ptr(rt->_rt6i_peer);
+}
+
+static inline bool rt6_has_peer(struct rt6_info *rt)
+{
+	return inetpeer_ptr_is_peer(rt->_rt6i_peer);
+}
+
+static inline void __rt6_set_peer(struct rt6_info *rt, struct inet_peer *peer)
+{
+	__inetpeer_ptr_set_peer(&rt->_rt6i_peer, peer);
+}
+
+static inline bool rt6_set_peer(struct rt6_info *rt, struct inet_peer *peer)
+{
+	return inetpeer_ptr_set_peer(&rt->_rt6i_peer, peer);
+}
+
+static inline void rt6_init_peer(struct rt6_info *rt, struct inet_peer_base *base)
+{
+	inetpeer_init_ptr(&rt->_rt6i_peer, base);
+}
+
+static inline void rt6_transfer_peer(struct rt6_info *rt, struct rt6_info *ort)
+{
+	inetpeer_transfer_peer(&rt->_rt6i_peer, &ort->_rt6i_peer);
+}
+
 static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 {
 	return ((struct rt6_info *)dst)->rt6i_idev;
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 73d7502..f88a85c 100644
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -57,11 +57,11 @@  extern void rt6_bind_peer(struct rt6_info *rt, int create);
 
 static inline struct inet_peer *__rt6_get_peer(struct rt6_info *rt, int create)
 {
-	if (rt->rt6i_peer)
-		return rt->rt6i_peer;
+	if (rt6_has_peer(rt))
+		return rt6_peer_ptr(rt);
 
 	rt6_bind_peer(rt, create);
-	return rt->rt6i_peer;
+	return rt6_peer_ptr(rt);
 }
 
 static inline struct inet_peer *rt6_get_peer(struct rt6_info *rt)
diff --git a/include/net/route.h b/include/net/route.h
index 433fc6c..6340c37 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -67,10 +67,44 @@  struct rtable {
 	/* Miscellaneous cached information */
 	__be32			rt_spec_dst; /* RFC1122 specific destination */
 	u32			rt_peer_genid;
-	struct inet_peer	*peer; /* long-living peer info */
+	unsigned long		_peer; /* long-living peer info */
 	struct fib_info		*fi; /* for client ref to shared metrics */
 };
 
+static inline struct inet_peer *rt_peer_ptr(struct rtable *rt)
+{
+	return inetpeer_ptr(rt->_peer);
+}
+
+static inline bool rt_has_peer(struct rtable *rt)
+{
+	return inetpeer_ptr_is_peer(rt->_peer);
+}
+
+static inline void __rt_set_peer(struct rtable *rt, struct inet_peer *peer)
+{
+	__inetpeer_ptr_set_peer(&rt->_peer, peer);
+}
+
+static inline bool rt_set_peer(struct rtable *rt, struct inet_peer *peer)
+{
+	return inetpeer_ptr_set_peer(&rt->_peer, peer);
+}
+
+static inline void rt_init_peer(struct rtable *rt, struct inet_peer_base *base)
+{
+	inetpeer_init_ptr(&rt->_peer, base);
+}
+
+static inline void rt_transfer_peer(struct rtable *rt, struct rtable *ort)
+{
+	rt->_peer = ort->_peer;
+	if (rt_has_peer(ort)) {
+		struct inet_peer *peer = rt_peer_ptr(ort);
+		atomic_inc(&peer->refcnt);
+	}
+}
+
 static inline bool rt_is_input_route(const struct rtable *rt)
 {
 	return rt->rt_route_iif != 0;
@@ -298,11 +332,11 @@  extern void rt_bind_peer(struct rtable *rt, __be32 daddr, int create);
 
 static inline struct inet_peer *__rt_get_peer(struct rtable *rt, __be32 daddr, int create)
 {
-	if (rt->peer)
-		return rt->peer;
+	if (rt_has_peer(rt))
+		return rt_peer_ptr(rt);
 
 	rt_bind_peer(rt, daddr, create);
-	return rt->peer;
+	return rt_peer_ptr(rt);
 }
 
 static inline struct inet_peer *rt_get_peer(struct rtable *rt, __be32 daddr)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 2aa663a..03e5b61 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -677,7 +677,7 @@  static inline int rt_fast_clean(struct rtable *rth)
 static inline int rt_valuable(struct rtable *rth)
 {
 	return (rth->rt_flags & (RTCF_REDIRECTED | RTCF_NOTIFY)) ||
-		(rth->peer && rth->peer->pmtu_expires);
+		(rt_has_peer(rth) && rt_peer_ptr(rth)->pmtu_expires);
 }
 
 static int rt_may_expire(struct rtable *rth, unsigned long tmo1, unsigned long tmo2)
@@ -1325,12 +1325,16 @@  static u32 rt_peer_genid(void)
 
 void rt_bind_peer(struct rtable *rt, __be32 daddr, int create)
 {
-	struct net *net = dev_net(rt->dst.dev);
+	struct inet_peer_base *base;
 	struct inet_peer *peer;
 
-	peer = inet_getpeer_v4(net->ipv4.peers, daddr, create);
+	base = inetpeer_base_ptr(rt->_peer);
+	if (!base)
+		return;
+
+	peer = inet_getpeer_v4(base, daddr, create);
 
-	if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
+	if (!rt_set_peer(rt, peer))
 		inet_putpeer(peer);
 	else
 		rt->rt_peer_genid = rt_peer_genid();
@@ -1533,8 +1537,10 @@  static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)
 						rt_genid(dev_net(dst->dev)));
 			rt_del(hash, rt);
 			ret = NULL;
-		} else if (rt->peer && peer_pmtu_expired(rt->peer)) {
-			dst_metric_set(dst, RTAX_MTU, rt->peer->pmtu_orig);
+		} else if (rt_has_peer(rt)) {
+			struct inet_peer *peer = rt_peer_ptr(rt);
+			if (peer_pmtu_expired(peer))
+				dst_metric_set(dst, RTAX_MTU, peer->pmtu_orig);
 		}
 	}
 	return ret;
@@ -1796,14 +1802,13 @@  static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
 static void ipv4_dst_destroy(struct dst_entry *dst)
 {
 	struct rtable *rt = (struct rtable *) dst;
-	struct inet_peer *peer = rt->peer;
 
 	if (rt->fi) {
 		fib_info_put(rt->fi);
 		rt->fi = NULL;
 	}
-	if (peer) {
-		rt->peer = NULL;
+	if (rt_has_peer(rt)) {
+		struct inet_peer *peer = rt_peer_ptr(rt);
 		inet_putpeer(peer);
 	}
 }
@@ -1816,8 +1821,11 @@  static void ipv4_link_failure(struct sk_buff *skb)
 	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
 
 	rt = skb_rtable(skb);
-	if (rt && rt->peer && peer_pmtu_cleaned(rt->peer))
-		dst_metric_set(&rt->dst, RTAX_MTU, rt->peer->pmtu_orig);
+	if (rt && rt_has_peer(rt)) {
+		struct inet_peer *peer = rt_peer_ptr(rt);
+		if (peer_pmtu_cleaned(peer))
+			dst_metric_set(&rt->dst, RTAX_MTU, peer->pmtu_orig);
+	}
 }
 
 static int ip_rt_bug(struct sk_buff *skb)
@@ -1919,7 +1927,7 @@  static unsigned int ipv4_mtu(const struct dst_entry *dst)
 static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
 			    struct fib_info *fi)
 {
-	struct net *net = dev_net(rt->dst.dev);
+	struct inet_peer_base *base;
 	struct inet_peer *peer;
 	int create = 0;
 
@@ -1929,8 +1937,12 @@  static void rt_init_metrics(struct rtable *rt, const struct flowi4 *fl4,
 	if (fl4 && (fl4->flowi4_flags & FLOWI_FLAG_PRECOW_METRICS))
 		create = 1;
 
-	rt->peer = peer = inet_getpeer_v4(net->ipv4.peers, rt->rt_dst, create);
+	base = inetpeer_base_ptr(rt->_peer);
+	BUG_ON(!base);
+
+	peer = inet_getpeer_v4(base, rt->rt_dst, create);
 	if (peer) {
+		__rt_set_peer(rt, peer);
 		rt->rt_peer_genid = rt_peer_genid();
 		if (inet_metrics_new(peer))
 			memcpy(peer->metrics, fi->fib_metrics,
@@ -2046,7 +2058,7 @@  static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(dev)->ipv4.peers);
 	rth->fi = NULL;
 	if (our) {
 		rth->dst.input= ip_local_deliver;
@@ -2174,7 +2186,7 @@  static int __mkroute_input(struct sk_buff *skb,
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(rth->dst.dev)->ipv4.peers);
 	rth->fi = NULL;
 
 	rth->dst.input = ip_forward;
@@ -2357,7 +2369,7 @@  local_input:
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, net->ipv4.peers);
 	rth->fi = NULL;
 	if (res.type == RTN_UNREACHABLE) {
 		rth->dst.input= ip_error;
@@ -2561,7 +2573,7 @@  static struct rtable *__mkroute_output(const struct fib_result *res,
 	rth->rt_gateway = fl4->daddr;
 	rth->rt_spec_dst= fl4->saddr;
 	rth->rt_peer_genid = 0;
-	rth->peer = NULL;
+	rt_init_peer(rth, dev_net(dev_out)->ipv4.peers);
 	rth->fi = NULL;
 
 	RT_CACHE_STAT_INC(out_slow_tot);
@@ -2898,9 +2910,7 @@  struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
 		rt->rt_src = ort->rt_src;
 		rt->rt_gateway = ort->rt_gateway;
 		rt->rt_spec_dst = ort->rt_spec_dst;
-		rt->peer = ort->peer;
-		if (rt->peer)
-			atomic_inc(&rt->peer->refcnt);
+		rt_transfer_peer(rt, ort);
 		rt->fi = ort->fi;
 		if (rt->fi)
 			atomic_inc(&rt->fi->fib_clntref);
@@ -2938,7 +2948,6 @@  static int rt_fill_info(struct net *net,
 	struct rtmsg *r;
 	struct nlmsghdr *nlh;
 	unsigned long expires = 0;
-	const struct inet_peer *peer = rt->peer;
 	u32 id = 0, ts = 0, tsage = 0, error;
 
 	nlh = nlmsg_put(skb, pid, seq, event, sizeof(*r), flags);
@@ -2994,8 +3003,9 @@  static int rt_fill_info(struct net *net,
 		goto nla_put_failure;
 
 	error = rt->dst.error;
-	if (peer) {
-		inet_peer_refcheck(rt->peer);
+	if (rt_has_peer(rt)) {
+		const struct inet_peer *peer = rt_peer_ptr(rt);
+		inet_peer_refcheck(peer);
 		id = atomic_read(&peer->ip_id_count) & 0xffff;
 		if (peer->tcp_ts_stamp) {
 			ts = peer->tcp_ts;
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 0d3426c..8855d82 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -90,9 +90,7 @@  static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	xdst->u.dst.dev = dev;
 	dev_hold(dev);
 
-	xdst->u.rt.peer = rt->peer;
-	if (rt->peer)
-		atomic_inc(&rt->peer->refcnt);
+	rt_transfer_peer(&xdst->u.rt, rt);
 
 	/* Sheit... I remember I did this right. Apparently,
 	 * it was magically lost, so this code needs audit */
@@ -212,8 +210,10 @@  static void xfrm4_dst_destroy(struct dst_entry *dst)
 
 	dst_destroy_metrics_generic(dst);
 
-	if (likely(xdst->u.rt.peer))
-		inet_putpeer(xdst->u.rt.peer);
+	if (rt_has_peer(&xdst->u.rt)) {
+		struct inet_peer *peer = rt_peer_ptr(&xdst->u.rt);
+		inet_putpeer(peer);
+	}
 
 	xfrm_dst_destroy(xdst);
 }
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 8fc41d5..17a9b86 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -258,16 +258,18 @@  static struct rt6_info ip6_blk_hole_entry_template = {
 #endif
 
 /* allocate dst with ip6_dst_ops */
-static inline struct rt6_info *ip6_dst_alloc(struct dst_ops *ops,
+static inline struct rt6_info *ip6_dst_alloc(struct net *net,
 					     struct net_device *dev,
 					     int flags)
 {
-	struct rt6_info *rt = dst_alloc(ops, dev, 0, 0, flags);
+	struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev,
+					0, 0, flags);
 
-	if (rt)
+	if (rt) {
 		memset(&rt->rt6i_table, 0,
 		       sizeof(*rt) - sizeof(struct dst_entry));
-
+		rt6_init_peer(rt, net->ipv6.peers);
+	}
 	return rt;
 }
 
@@ -275,7 +277,6 @@  static void ip6_dst_destroy(struct dst_entry *dst)
 {
 	struct rt6_info *rt = (struct rt6_info *)dst;
 	struct inet6_dev *idev = rt->rt6i_idev;
-	struct inet_peer *peer = rt->rt6i_peer;
 
 	if (!(rt->dst.flags & DST_HOST))
 		dst_destroy_metrics_generic(dst);
@@ -288,8 +289,8 @@  static void ip6_dst_destroy(struct dst_entry *dst)
 	if (!(rt->rt6i_flags & RTF_EXPIRES) && dst->from)
 		dst_release(dst->from);
 
-	if (peer) {
-		rt->rt6i_peer = NULL;
+	if (rt6_has_peer(rt)) {
+		struct inet_peer *peer = rt6_peer_ptr(rt);
 		inet_putpeer(peer);
 	}
 }
@@ -303,11 +304,15 @@  static u32 rt6_peer_genid(void)
 
 void rt6_bind_peer(struct rt6_info *rt, int create)
 {
-	struct net *net = dev_net(rt->dst.dev);
+	struct inet_peer_base *base;
 	struct inet_peer *peer;
 
-	peer = inet_getpeer_v6(net->ipv6.peers, &rt->rt6i_dst.addr, create);
-	if (peer && cmpxchg(&rt->rt6i_peer, NULL, peer) != NULL)
+	base = inetpeer_base_ptr(rt->_rt6i_peer);
+	if (!base)
+		return;
+
+	peer = inet_getpeer_v6(base, &rt->rt6i_dst.addr, create);
+	if (!rt6_set_peer(rt, peer))
 		inet_putpeer(peer);
 	else
 		rt->rt6i_peer_genid = rt6_peer_genid();
@@ -950,6 +955,7 @@  struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
 	rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, 0, 0);
 	if (rt) {
 		memset(&rt->rt6i_table, 0, sizeof(*rt) - sizeof(struct dst_entry));
+		rt6_init_peer(rt, net->ipv6.peers);
 
 		new = &rt->dst;
 
@@ -994,7 +1000,7 @@  static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie)
 
 	if (rt->rt6i_node && (rt->rt6i_node->fn_sernum == cookie)) {
 		if (rt->rt6i_peer_genid != rt6_peer_genid()) {
-			if (!rt->rt6i_peer)
+			if (!rt6_has_peer(rt))
 				rt6_bind_peer(rt, 0);
 			rt->rt6i_peer_genid = rt6_peer_genid();
 		}
@@ -1108,7 +1114,7 @@  struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
 	if (unlikely(!idev))
 		return ERR_PTR(-ENODEV);
 
-	rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops, dev, 0);
+	rt = ip6_dst_alloc(net, dev, 0);
 	if (unlikely(!rt)) {
 		in6_dev_put(idev);
 		dst = ERR_PTR(-ENOMEM);
@@ -1290,7 +1296,7 @@  int ip6_route_add(struct fib6_config *cfg)
 	if (!table)
 		goto out;
 
-	rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops, NULL, DST_NOCOUNT);
+	rt = ip6_dst_alloc(net, NULL, DST_NOCOUNT);
 
 	if (!rt) {
 		err = -ENOMEM;
@@ -1812,8 +1818,7 @@  static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
 				    const struct in6_addr *dest)
 {
 	struct net *net = dev_net(ort->dst.dev);
-	struct rt6_info *rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops,
-					    ort->dst.dev, 0);
+	struct rt6_info *rt = ip6_dst_alloc(net, ort->dst.dev, 0);
 
 	if (rt) {
 		rt->dst.input = ort->dst.input;
@@ -2097,8 +2102,7 @@  struct rt6_info *addrconf_dst_alloc(struct inet6_dev *idev,
 				    bool anycast)
 {
 	struct net *net = dev_net(idev->dev);
-	struct rt6_info *rt = ip6_dst_alloc(&net->ipv6.ip6_dst_ops,
-					    net->loopback_dev, 0);
+	struct rt6_info *rt = ip6_dst_alloc(net, net->loopback_dev, 0);
 	int err;
 
 	if (!rt) {
@@ -2519,7 +2523,9 @@  static int rt6_fill_node(struct net *net,
 	else
 		expires = INT_MAX;
 
-	peer = rt->rt6i_peer;
+	peer = NULL;
+	if (rt6_has_peer(rt))
+		peer = rt6_peer_ptr(rt);
 	ts = tsage = 0;
 	if (peer && peer->tcp_ts_stamp) {
 		ts = peer->tcp_ts;
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 8625fba..d749484 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -99,9 +99,7 @@  static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
 	if (!xdst->u.rt6.rt6i_idev)
 		return -ENODEV;
 
-	xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
-	if (rt->rt6i_peer)
-		atomic_inc(&rt->rt6i_peer->refcnt);
+	rt6_transfer_peer(&xdst->u.rt6, rt);
 
 	/* Sheit... I remember I did this right. Apparently,
 	 * it was magically lost, so this code needs audit */
@@ -223,8 +221,10 @@  static void xfrm6_dst_destroy(struct dst_entry *dst)
 	if (likely(xdst->u.rt6.rt6i_idev))
 		in6_dev_put(xdst->u.rt6.rt6i_idev);
 	dst_destroy_metrics_generic(dst);
-	if (likely(xdst->u.rt6.rt6i_peer))
-		inet_putpeer(xdst->u.rt6.rt6i_peer);
+	if (rt6_has_peer(&xdst->u.rt6)) {
+		struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
+		inet_putpeer(peer);
+	}
 	xfrm_dst_destroy(xdst);
 }