1 files changed, 126 insertions, 139 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ac6559cb54f9..987bf9adb318 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -159,7 +159,6 @@ static struct dst_ops ipv4_dst_ops = {
 	.link_failure =		ipv4_link_failure,
 	.update_pmtu =		ip_rt_update_pmtu,
 	.local_out =		__ip_local_out,
-	.entries =		ATOMIC_INIT(0),
 };
 
 #define ECN_OR_COST(class)	TC_PRIO_##class
@@ -199,7 +198,7 @@ const __u8 ip_tos2prio[16] = {
  */
 
 struct rt_hash_bucket {
-	struct rtable	*chain;
+	struct rtable __rcu	*chain;
 };
 
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
@@ -281,7 +280,7 @@ static struct rtable *rt_cache_get_first(struct seq_file *seq)
 	struct rtable *r = NULL;
 
 	for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
-		if (!rt_hash_table[st->bucket].chain)
+		if (!rcu_dereference_raw(rt_hash_table[st->bucket].chain))
 			continue;
 		rcu_read_lock_bh();
 		r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
@@ -301,17 +300,17 @@ static struct rtable *__rt_cache_get_next(struct seq_file *seq,
 {
 	struct rt_cache_iter_state *st = seq->private;
 
-	r = r->dst.rt_next;
+	r = rcu_dereference_bh(r->dst.rt_next);
 	while (!r) {
 		rcu_read_unlock_bh();
 		do {
 			if (--st->bucket < 0)
 				return NULL;
-		} while (!rt_hash_table[st->bucket].chain);
+		} while (!rcu_dereference_raw(rt_hash_table[st->bucket].chain));
 		rcu_read_lock_bh();
-		r = rt_hash_table[st->bucket].chain;
+		r = rcu_dereference_bh(rt_hash_table[st->bucket].chain);
 	}
-	return rcu_dereference_bh(r);
+	return r;
 }
 
 static struct rtable *rt_cache_get_next(struct seq_file *seq,
@@ -466,7 +465,7 @@ static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 
 	seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
 		   " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
-		   atomic_read(&ipv4_dst_ops.entries),
+		   dst_entries_get_slow(&ipv4_dst_ops),
 		   st->in_hit,
 		   st->in_slow_tot,
 		   st->in_slow_mc,
@@ -722,19 +721,23 @@ static void rt_do_flush(int process_context)
 	for (i = 0; i <= rt_hash_mask; i++) {
 		if (process_context && need_resched())
 			cond_resched();
-		rth = rt_hash_table[i].chain;
+		rth = rcu_dereference_raw(rt_hash_table[i].chain);
 		if (!rth)
 			continue;
 
 		spin_lock_bh(rt_hash_lock_addr(i));
 #ifdef CONFIG_NET_NS
 		{
-		struct rtable ** prev, * p;
+		struct rtable __rcu **prev;
+		struct rtable *p;
 
-		rth = rt_hash_table[i].chain;
+		rth = rcu_dereference_protected(rt_hash_table[i].chain,
+			lockdep_is_held(rt_hash_lock_addr(i)));
 
 		/* defer releasing the head of the list after spin_unlock */
-		for (tail = rth; tail; tail = tail->dst.rt_next)
+		for (tail = rth; tail;
+		     tail = rcu_dereference_protected(tail->dst.rt_next,
+				lockdep_is_held(rt_hash_lock_addr(i))))
 			if (!rt_is_expired(tail))
 				break;
 		if (rth != tail)
@@ -742,8 +745,12 @@ static void rt_do_flush(int process_context)
 
 		/* call rt_free on entries after the tail requiring flush */
 		prev = &rt_hash_table[i].chain;
-		for (p = *prev; p; p = next) {
-			next = p->dst.rt_next;
+		for (p = rcu_dereference_protected(*prev,
+				lockdep_is_held(rt_hash_lock_addr(i)));
+		     p != NULL;
+		     p = next) {
+			next = rcu_dereference_protected(p->dst.rt_next,
+				lockdep_is_held(rt_hash_lock_addr(i)));
 			if (!rt_is_expired(p)) {
 				prev = &p->dst.rt_next;
 			} else {
@@ -753,14 +760,15 @@ static void rt_do_flush(int process_context)
 		}
 		}
 #else
-		rth = rt_hash_table[i].chain;
-		rt_hash_table[i].chain = NULL;
+		rth = rcu_dereference_protected(rt_hash_table[i].chain,
+			lockdep_is_held(rt_hash_lock_addr(i)));
+		rcu_assign_pointer(rt_hash_table[i].chain, NULL);
 		tail = NULL;
 #endif
 		spin_unlock_bh(rt_hash_lock_addr(i));
 
 		for (; rth != tail; rth = next) {
-			next = rth->dst.rt_next;
+			next = rcu_dereference_protected(rth->dst.rt_next, 1);
 			rt_free(rth);
 		}
 	}
@@ -791,7 +799,7 @@ static int has_noalias(const struct rtable *head, const struct rtable *rth)
 	while (aux != rth) {
 		if (compare_hash_inputs(&aux->fl, &rth->fl))
 			return 0;
-		aux = aux->dst.rt_next;
+		aux = rcu_dereference_protected(aux->dst.rt_next, 1);
 	}
 	return ONE;
 }
@@ -800,7 +808,8 @@ static void rt_check_expire(void)
 {
 	static unsigned int rover;
 	unsigned int i = rover, goal;
-	struct rtable *rth, **rthp;
+	struct rtable *rth;
+	struct rtable __rcu **rthp;
 	unsigned long samples = 0;
 	unsigned long sum = 0, sum2 = 0;
 	unsigned long delta;
@@ -826,11 +835,12 @@ static void rt_check_expire(void)
 
 		samples++;
 
-		if (*rthp == NULL)
+		if (rcu_dereference_raw(*rthp) == NULL)
 			continue;
 		length = 0;
 		spin_lock_bh(rt_hash_lock_addr(i));
-		while ((rth = *rthp) != NULL) {
+		while ((rth = rcu_dereference_protected(*rthp,
+					lockdep_is_held(rt_hash_lock_addr(i)))) != NULL) {
 			prefetch(rth->dst.rt_next);
 			if (rt_is_expired(rth)) {
 				*rthp = rth->dst.rt_next;
@@ -942,9 +952,11 @@ static int rt_garbage_collect(struct dst_ops *ops)
 	static unsigned long last_gc;
 	static int rover;
 	static int equilibrium;
-	struct rtable *rth, **rthp;
+	struct rtable *rth;
+	struct rtable __rcu **rthp;
 	unsigned long now = jiffies;
 	int goal;
+	int entries = dst_entries_get_fast(&ipv4_dst_ops);
 
 	/*
 	 * Garbage collection is pretty expensive,
@@ -954,28 +966,28 @@ static int rt_garbage_collect(struct dst_ops *ops)
 	RT_CACHE_STAT_INC(gc_total);
 
 	if (now - last_gc < ip_rt_gc_min_interval &&
-	    atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size) {
+	    entries < ip_rt_max_size) {
 		RT_CACHE_STAT_INC(gc_ignored);
 		goto out;
 	}
 
+	entries = dst_entries_get_slow(&ipv4_dst_ops);
 	/* Calculate number of entries, which we want to expire now. */
-	goal = atomic_read(&ipv4_dst_ops.entries) -
-		(ip_rt_gc_elasticity << rt_hash_log);
+	goal = entries - (ip_rt_gc_elasticity << rt_hash_log);
 	if (goal <= 0) {
 		if (equilibrium < ipv4_dst_ops.gc_thresh)
 			equilibrium = ipv4_dst_ops.gc_thresh;
-		goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
+		goal = entries - equilibrium;
 		if (goal > 0) {
 			equilibrium += min_t(unsigned int, goal >> 1, rt_hash_mask + 1);
-			goal = atomic_read(&ipv4_dst_ops.entries) - equilibrium;
+			goal = entries - equilibrium;
 		}
 	} else {
 		/* We are in dangerous area. Try to reduce cache really
 		 * aggressively.
 		 */
 		goal = max_t(unsigned int, goal >> 1, rt_hash_mask + 1);
-		equilibrium = atomic_read(&ipv4_dst_ops.entries) - goal;
+		equilibrium = entries - goal;
 	}
 
 	if (now - last_gc >= ip_rt_gc_min_interval)
@@ -995,7 +1007,8 @@ static int rt_garbage_collect(struct dst_ops *ops)
 			k = (k + 1) & rt_hash_mask;
 			rthp = &rt_hash_table[k].chain;
 			spin_lock_bh(rt_hash_lock_addr(k));
-			while ((rth = *rthp) != NULL) {
+			while ((rth = rcu_dereference_protected(*rthp,
+					lockdep_is_held(rt_hash_lock_addr(k)))) != NULL) {
 				if (!rt_is_expired(rth) &&
 					!rt_may_expire(rth, tmo, expire)) {
 					tmo >>= 1;
@@ -1032,14 +1045,16 @@ static int rt_garbage_collect(struct dst_ops *ops)
 		expire >>= 1;
 #if RT_CACHE_DEBUG >= 2
 		printk(KERN_DEBUG "expire>> %u %d %d %d\n", expire,
-				atomic_read(&ipv4_dst_ops.entries), goal, i);
+				dst_entries_get_fast(&ipv4_dst_ops), goal, i);
 #endif
 
-		if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
+		if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
 			goto out;
 	} while (!in_softirq() && time_before_eq(jiffies, now));
 
-	if (atomic_read(&ipv4_dst_ops.entries) < ip_rt_max_size)
+	if (dst_entries_get_fast(&ipv4_dst_ops) < ip_rt_max_size)
+		goto out;
+	if (dst_entries_get_slow(&ipv4_dst_ops) < ip_rt_max_size)
 		goto out;
 	if (net_ratelimit())
 		printk(KERN_WARNING "dst cache overflow\n");
@@ -1049,11 +1064,12 @@ static int rt_garbage_collect(struct dst_ops *ops)
 work_done:
 	expire += ip_rt_gc_min_interval;
 	if (expire > ip_rt_gc_timeout ||
-	    atomic_read(&ipv4_dst_ops.entries) < ipv4_dst_ops.gc_thresh)
+	    dst_entries_get_fast(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh ||
+	    dst_entries_get_slow(&ipv4_dst_ops) < ipv4_dst_ops.gc_thresh)
 		expire = ip_rt_gc_timeout;
 #if RT_CACHE_DEBUG >= 2
 	printk(KERN_DEBUG "expire++ %u %d %d %d\n", expire,
-			atomic_read(&ipv4_dst_ops.entries), goal, rover);
+			dst_entries_get_fast(&ipv4_dst_ops), goal, rover);
 #endif
 out:	return 0;
 }
@@ -1068,7 +1084,7 @@ static int slow_chain_length(const struct rtable *head)
 
 	while (rth) {
 		length += has_noalias(head, rth);
-		rth = rth->dst.rt_next;
+		rth = rcu_dereference_protected(rth->dst.rt_next, 1);
 	}
 	return length >> FRACT_BITS;
 }
@@ -1076,9 +1092,9 @@ static int slow_chain_length(const struct rtable *head)
 static int rt_intern_hash(unsigned hash, struct rtable *rt,
 			  struct rtable **rp, struct sk_buff *skb, int ifindex)
 {
-	struct rtable	*rth, **rthp;
+	struct rtable	*rth, *cand;
+	struct rtable __rcu **rthp, **candp;
 	unsigned long	now;
-	struct rtable *cand, **candp;
 	u32 		min_score;
 	int		chain_length;
 	int attempts = !in_softirq();
@@ -1102,30 +1118,31 @@ restart:
 		 * Note that we do rt_free on this new route entry, so that
 		 * once its refcount hits zero, we are still able to reap it
 		 * (Thanks Alexey)
-		 * Note also the rt_free uses call_rcu.  We don't actually
-		 * need rcu protection here, this is just our path to get
-		 * on the route gc list.
+		 * Note: To avoid expensive rcu stuff for this uncached dst,
+		 * we set DST_NOCACHE so that dst_release() can free dst without
+		 * waiting a grace period.
 		 */
 
+		rt->dst.flags |= DST_NOCACHE;
 		if (rt->rt_type == RTN_UNICAST || rt->fl.iif == 0) {
 			int err = arp_bind_neighbour(&rt->dst);
 			if (err) {
 				if (net_ratelimit())
 					printk(KERN_WARNING
 					    "Neighbour table failure & not caching routes.\n");
-				rt_drop(rt);
+				ip_rt_put(rt);
 				return err;
 			}
 		}
 
-		rt_free(rt);
 		goto skip_hashing;
 	}
 
 	rthp = &rt_hash_table[hash].chain;
 
 	spin_lock_bh(rt_hash_lock_addr(hash));
-	while ((rth = *rthp) != NULL) {
+	while ((rth = rcu_dereference_protected(*rthp,
+			lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
 		if (rt_is_expired(rth)) {
 			*rthp = rth->dst.rt_next;
 			rt_free(rth);
@@ -1268,18 +1285,11 @@ skip_hashing:
 
 void rt_bind_peer(struct rtable *rt, int create)
 {
-	static DEFINE_SPINLOCK(rt_peer_lock);
 	struct inet_peer *peer;
 
 	peer = inet_getpeer(rt->rt_dst, create);
 
-	spin_lock_bh(&rt_peer_lock);
-	if (rt->peer == NULL) {
-		rt->peer = peer;
-		peer = NULL;
-	}
-	spin_unlock_bh(&rt_peer_lock);
-	if (peer)
+	if (peer && cmpxchg(&rt->peer, NULL, peer) != NULL)
 		inet_putpeer(peer);
 }
 
@@ -1328,12 +1338,14 @@ EXPORT_SYMBOL(__ip_select_ident);
 
 static void rt_del(unsigned hash, struct rtable *rt)
 {
-	struct rtable **rthp, *aux;
+	struct rtable __rcu **rthp;
+	struct rtable *aux;
 
 	rthp = &rt_hash_table[hash].chain;
 	spin_lock_bh(rt_hash_lock_addr(hash));
 	ip_rt_put(rt);
-	while ((aux = *rthp) != NULL) {
+	while ((aux = rcu_dereference_protected(*rthp,
+			lockdep_is_held(rt_hash_lock_addr(hash)))) != NULL) {
 		if (aux == rt || rt_is_expired(aux)) {
 			*rthp = aux->dst.rt_next;
 			rt_free(aux);
@@ -1350,7 +1362,8 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 {
 	int i, k;
 	struct in_device *in_dev = __in_dev_get_rcu(dev);
-	struct rtable *rth, **rthp;
+	struct rtable *rth;
+	struct rtable __rcu **rthp;
 	__be32  skeys[2] = { saddr, 0 };
 	int  ikeys[2] = { dev->ifindex, 0 };
 	struct netevent_redirect netevent;
@@ -1383,7 +1396,7 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 			unsigned hash = rt_hash(daddr, skeys[i], ikeys[k],
 						rt_genid(net));
 
-			rthp=&rt_hash_table[hash].chain;
+			rthp = &rt_hash_table[hash].chain;
 
 			while ((rth = rcu_dereference(*rthp)) != NULL) {
 				struct rtable *rt;
@@ -1779,12 +1792,15 @@ void ip_rt_get_source(u8 *addr, struct rtable *rt)
 
 	if (rt->fl.iif == 0)
 		src = rt->rt_src;
-	else if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0) {
-		src = FIB_RES_PREFSRC(res);
-		fib_res_put(&res);
-	} else
-		src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
+	else {
+		rcu_read_lock();
+		if (fib_lookup(dev_net(rt->dst.dev), &rt->fl, &res) == 0)
+			src = FIB_RES_PREFSRC(res);
+		else
+			src = inet_select_addr(rt->dst.dev, rt->rt_gateway,
 					RT_SCOPE_UNIVERSE);
+		rcu_read_unlock();
+	}
 	memcpy(addr, &src, 4);
 }
 
@@ -2087,6 +2103,7 @@ static int ip_mkroute_input(struct sk_buff *skb,
  *	Such approach solves two big problems:
  *	1. Not simplex devices are handled properly.
  *	2. IP spoofing attempts are filtered with 100% of guarantee.
+ *	called with rcu_read_lock()
  */
 
 static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2108,7 +2125,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	unsigned	hash;
 	__be32		spec_dst;
 	int		err = -EINVAL;
-	int		free_res = 0;
 	struct net    * net = dev_net(dev);
 
 	/* IP on this device is disabled. */
@@ -2124,7 +2140,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	    ipv4_is_loopback(saddr))
 		goto martian_source;
 
-	if (daddr == htonl(0xFFFFFFFF) || (saddr == 0 && daddr == 0))
+	if (ipv4_is_lbcast(daddr) || (saddr == 0 && daddr == 0))
 		goto brd_input;
 
 	/* Accept zero addresses only to limited broadcast;
@@ -2133,19 +2149,18 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	if (ipv4_is_zeronet(saddr))
 		goto martian_source;
 
-	if (ipv4_is_lbcast(daddr) || ipv4_is_zeronet(daddr) ||
-	    ipv4_is_loopback(daddr))
+	if (ipv4_is_zeronet(daddr) || ipv4_is_loopback(daddr))
 		goto martian_destination;
 
 	/*
 	 *	Now we are ready to route packet.
 	 */
-	if ((err = fib_lookup(net, &fl, &res)) != 0) {
+	err = fib_lookup(net, &fl, &res);
+	if (err != 0) {
 		if (!IN_DEV_FORWARD(in_dev))
 			goto e_hostunreach;
 		goto no_route;
 	}
-	free_res = 1;
 
 	RT_CACHE_STAT_INC(in_slow_tot);
 
@@ -2154,8 +2169,8 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 
 	if (res.type == RTN_LOCAL) {
 		err = fib_validate_source(saddr, daddr, tos,
-					     net->loopback_dev->ifindex,
-					     dev, &spec_dst, &itag, skb->mark);
+					  net->loopback_dev->ifindex,
+					  dev, &spec_dst, &itag, skb->mark);
 		if (err < 0)
 			goto martian_source_keep_err;
 		if (err)
@@ -2170,9 +2185,6 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		goto martian_destination;
 
 	err = ip_mkroute_input(skb, &res, &fl, in_dev, daddr, saddr, tos);
-done:
-	if (free_res)
-		fib_res_put(&res);
 out:	return err;
 
 brd_input:
@@ -2232,7 +2244,7 @@ local_input:
 	rth->rt_type	= res.type;
 	hash = rt_hash(daddr, saddr, fl.iif, rt_genid(net));
 	err = rt_intern_hash(hash, rth, NULL, skb, fl.iif);
-	goto done;
+	goto out;
 
 no_route:
 	RT_CACHE_STAT_INC(in_no_route);
@@ -2255,21 +2267,21 @@ martian_destination:
 
 e_hostunreach:
 	err = -EHOSTUNREACH;
-	goto done;
+	goto out;
 
 e_inval:
 	err = -EINVAL;
-	goto done;
+	goto out;
 
 e_nobufs:
 	err = -ENOBUFS;
-	goto done;
+	goto out;
 
 martian_source:
 	err = -EINVAL;
 martian_source_keep_err:
 	ip_handle_martian_source(dev, in_dev, skb, daddr, saddr);
-	goto done;
+	goto out;
 }
 
 int ip_route_input_common(struct sk_buff *skb, __be32 daddr, __be32 saddr,
@@ -2355,6 +2367,7 @@ skip_cache:
 }
 EXPORT_SYMBOL(ip_route_input_common);
 
+/* called with rcu_read_lock() */
 static int __mkroute_output(struct rtable **result,
 			    struct fib_result *res,
 			    const struct flowi *fl,
@@ -2365,53 +2378,47 @@ static int __mkroute_output(struct rtable **result,
 	struct rtable *rth;
 	struct in_device *in_dev;
 	u32 tos = RT_FL_TOS(oldflp);
-	int err = 0;
 
-	if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags&IFF_LOOPBACK))
+	if (ipv4_is_loopback(fl->fl4_src) && !(dev_out->flags & IFF_LOOPBACK))
 		return -EINVAL;
 
-	if (fl->fl4_dst == htonl(0xFFFFFFFF))
+	if (ipv4_is_lbcast(fl->fl4_dst))
 		res->type = RTN_BROADCAST;
 	else if (ipv4_is_multicast(fl->fl4_dst))
 		res->type = RTN_MULTICAST;
-	else if (ipv4_is_lbcast(fl->fl4_dst) || ipv4_is_zeronet(fl->fl4_dst))
+	else if (ipv4_is_zeronet(fl->fl4_dst))
 		return -EINVAL;
 
 	if (dev_out->flags & IFF_LOOPBACK)
 		flags |= RTCF_LOCAL;
 
-	/* get work reference to inet device */
-	in_dev = in_dev_get(dev_out);
+	in_dev = __in_dev_get_rcu(dev_out);
 	if (!in_dev)
 		return -EINVAL;
 
 	if (res->type == RTN_BROADCAST) {
 		flags |= RTCF_BROADCAST | RTCF_LOCAL;
-		if (res->fi) {
-			fib_info_put(res->fi);
-			res->fi = NULL;
-		}
+		res->fi = NULL;
 	} else if (res->type == RTN_MULTICAST) {
-		flags |= RTCF_MULTICAST|RTCF_LOCAL;
+		flags |= RTCF_MULTICAST | RTCF_LOCAL;
 		if (!ip_check_mc(in_dev, oldflp->fl4_dst, oldflp->fl4_src,
 				 oldflp->proto))
 			flags &= ~RTCF_LOCAL;
 		/* If multicast route do not exist use
-		   default one, but do not gateway in this case.
-		   Yes, it is hack.
+		 * default one, but do not gateway in this case.
+		 * Yes, it is hack.
 		 */
-		if (res->fi && res->prefixlen < 4) {
-			fib_info_put(res->fi);
+		if (res->fi && res->prefixlen < 4)
 			res->fi = NULL;
-		}
 	}
 
 
 	rth = dst_alloc(&ipv4_dst_ops);
-	if (!rth) {
-		err = -ENOBUFS;
-		goto cleanup;
-	}
+	if (!rth)
+		return -ENOBUFS;
+
+	in_dev_hold(in_dev);
+	rth->idev = in_dev;
 
 	atomic_set(&rth->dst.__refcnt, 1);
 	rth->dst.flags= DST_HOST;
@@ -2432,7 +2439,6 @@ static int __mkroute_output(struct rtable **result,
 	   cache entry */
 	rth->dst.dev	= dev_out;
 	dev_hold(dev_out);
-	rth->idev	= in_dev_get(dev_out);
 	rth->rt_gateway = fl->fl4_dst;
 	rth->rt_spec_dst= fl->fl4_src;
 
@@ -2467,15 +2473,11 @@ static int __mkroute_output(struct rtable **result,
 	rt_set_nexthop(rth, res, 0);
 
 	rth->rt_flags = flags;
-
 	*result = rth;
- cleanup:
-	/* release work reference to inet device */
-	in_dev_put(in_dev);
-
-	return err;
+	return 0;
 }
 
+/* called with rcu_read_lock() */
 static int ip_mkroute_output(struct rtable **rp,
 			     struct fib_result *res,
 			     const struct flowi *fl,
@@ -2497,6 +2499,7 @@ static int ip_mkroute_output(struct rtable **rp,
 
 /*
  * Major route resolver routine.
+ * called with rcu_read_lock();
  */
 
 static int ip_route_output_slow(struct net *net, struct rtable **rp,
@@ -2515,9 +2518,8 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 			    .iif = net->loopback_dev->ifindex,
 			    .oif = oldflp->oif };
 	struct fib_result res;
-	unsigned flags = 0;
+	unsigned int flags = 0;
 	struct net_device *dev_out = NULL;
-	int free_res = 0;
 	int err;
 
 
@@ -2543,9 +2545,9 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 
 		if (oldflp->oif == 0 &&
 		    (ipv4_is_multicast(oldflp->fl4_dst) ||
-		     oldflp->fl4_dst == htonl(0xFFFFFFFF))) {
+		     ipv4_is_lbcast(oldflp->fl4_dst))) {
 			/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
-			dev_out = ip_dev_find(net, oldflp->fl4_src);
+			dev_out = __ip_dev_find(net, oldflp->fl4_src, false);
 			if (dev_out == NULL)
 				goto out;
 
@@ -2570,29 +2572,24 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 
 		if (!(oldflp->flags & FLOWI_FLAG_ANYSRC)) {
 			/* It is equivalent to inet_addr_type(saddr) == RTN_LOCAL */
-			dev_out = ip_dev_find(net, oldflp->fl4_src);
-			if (dev_out == NULL)
+			if (!__ip_dev_find(net, oldflp->fl4_src, false))
 				goto out;
-			dev_put(dev_out);
-			dev_out = NULL;
 		}
 	}
 
 
 	if (oldflp->oif) {
-		dev_out = dev_get_by_index(net, oldflp->oif);
+		dev_out = dev_get_by_index_rcu(net, oldflp->oif);
 		err = -ENODEV;
 		if (dev_out == NULL)
 			goto out;
 
 		/* RACE: Check return value of inet_select_addr instead. */
-		if (__in_dev_get_rtnl(dev_out) == NULL) {
-			dev_put(dev_out);
+		if (rcu_dereference(dev_out->ip_ptr) == NULL)
 			goto out;	/* Wrong error code */
-		}
 
 		if (ipv4_is_local_multicast(oldflp->fl4_dst) ||
-		    oldflp->fl4_dst == htonl(0xFFFFFFFF)) {
+		    ipv4_is_lbcast(oldflp->fl4_dst)) {
 			if (!fl.fl4_src)
 				fl.fl4_src = inet_select_addr(dev_out, 0,
 							      RT_SCOPE_LINK);
@@ -2612,10 +2609,7 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 		fl.fl4_dst = fl.fl4_src;
 		if (!fl.fl4_dst)
 			fl.fl4_dst = fl.fl4_src = htonl(INADDR_LOOPBACK);
-		if (dev_out)
-			dev_put(dev_out);
 		dev_out = net->loopback_dev;
-		dev_hold(dev_out);
 		fl.oif = net->loopback_dev->ifindex;
 		res.type = RTN_LOCAL;
 		flags |= RTCF_LOCAL;
@@ -2649,23 +2643,15 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 			res.type = RTN_UNICAST;
 			goto make_route;
 		}
-		if (dev_out)
-			dev_put(dev_out);
 		err = -ENETUNREACH;
 		goto out;
 	}
-	free_res = 1;
 
 	if (res.type == RTN_LOCAL) {
 		if (!fl.fl4_src)
 			fl.fl4_src = fl.fl4_dst;
-		if (dev_out)
-			dev_put(dev_out);
 		dev_out = net->loopback_dev;
-		dev_hold(dev_out);
 		fl.oif = dev_out->ifindex;
-		if (res.fi)
-			fib_info_put(res.fi);
 		res.fi = NULL;
 		flags |= RTCF_LOCAL;
 		goto make_route;
@@ -2682,28 +2668,21 @@ static int ip_route_output_slow(struct net *net, struct rtable **rp,
 	if (!fl.fl4_src)
 		fl.fl4_src = FIB_RES_PREFSRC(res);
 
-	if (dev_out)
-		dev_put(dev_out);
 	dev_out = FIB_RES_DEV(res);
-	dev_hold(dev_out);
 	fl.oif = dev_out->ifindex;
 
 
 make_route:
 	err = ip_mkroute_output(rp, &res, &fl, oldflp, dev_out, flags);
 
-
-	if (free_res)
-		fib_res_put(&res);
-	if (dev_out)
-		dev_put(dev_out);
 out:	return err;
 }
 
 int __ip_route_output_key(struct net *net, struct rtable **rp,
 			  const struct flowi *flp)
 {
-	unsigned hash;
+	unsigned int hash;
+	int res;
 	struct rtable *rth;
 
 	if (!rt_caching(net))
@@ -2734,7 +2713,10 @@ int __ip_route_output_key(struct net *net, struct rtable **rp,
 	rcu_read_unlock_bh();
 
 slow_output:
-	return ip_route_output_slow(net, rp, flp);
+	rcu_read_lock();
+	res = ip_route_output_slow(net, rp, flp);
+	rcu_read_unlock();
+	return res;
 }
 EXPORT_SYMBOL_GPL(__ip_route_output_key);
 
@@ -2753,7 +2735,6 @@ static struct dst_ops ipv4_dst_blackhole_ops = {
 	.destroy		=	ipv4_dst_destroy,
 	.check			=	ipv4_blackhole_dst_check,
 	.update_pmtu		=	ipv4_rt_blackhole_update_pmtu,
-	.entries		=	ATOMIC_INIT(0),
 };
 
 
@@ -2798,7 +2779,7 @@ static int ipv4_dst_blackhole(struct net *net, struct rtable **rp, struct flowi
 
 	dst_release(&(*rp)->dst);
 	*rp = rt;
-	return (rt ? 0 : -ENOMEM);
+	return rt ? 0 : -ENOMEM;
 }
 
 int ip_route_output_flow(struct net *net, struct rtable **rp, struct flowi *flp,
@@ -3323,6 +3304,12 @@ int __init ip_rt_init(void)
 
 	ipv4_dst_blackhole_ops.kmem_cachep = ipv4_dst_ops.kmem_cachep;
 
+	if (dst_entries_init(&ipv4_dst_ops) < 0)
+		panic("IP: failed to allocate ipv4_dst_ops counter\n");
+
+	if (dst_entries_init(&ipv4_dst_blackhole_ops) < 0)
+		panic("IP: failed to allocate ipv4_dst_blackhole_ops counter\n");
+
 	rt_hash_table = (struct rt_hash_bucket *)
 		alloc_large_system_hash("IP route cache",
 					sizeof(struct rt_hash_bucket),