1 files changed, 89 insertions, 120 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 163086b2f058..8842ecb9be48 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -117,8 +117,6 @@
 
 #define RT_GC_TIMEOUT (300*HZ)
 
-static int ip_rt_min_delay		= 2 * HZ;
-static int ip_rt_max_delay		= 10 * HZ;
 static int ip_rt_max_size;
 static int ip_rt_gc_timeout		= RT_GC_TIMEOUT;
 static int ip_rt_gc_interval		= 60 * HZ;
@@ -133,12 +131,9 @@ static int ip_rt_mtu_expires		= 10 * 60 * HZ;
 static int ip_rt_min_pmtu		= 512 + 20 + 20;
 static int ip_rt_min_advmss		= 256;
 static int ip_rt_secret_interval	= 10 * 60 * HZ;
-static int ip_rt_flush_expected;
-static unsigned long rt_deadline;
 
 #define RTprint(a...)	printk(KERN_DEBUG a)
 
-static struct timer_list rt_flush_timer;
 static void rt_worker_func(struct work_struct *work);
 static DECLARE_DELAYED_WORK(expires_work, rt_worker_func);
 static struct timer_list rt_secret_timer;
@@ -260,19 +255,16 @@ static inline void rt_hash_lock_init(void)
 static struct rt_hash_bucket 	*rt_hash_table;
 static unsigned			rt_hash_mask;
 static unsigned int		rt_hash_log;
-static unsigned int		rt_hash_rnd;
+static atomic_t			rt_genid;
 
 static DEFINE_PER_CPU(struct rt_cache_stat, rt_cache_stat);
 #define RT_CACHE_STAT_INC(field) \
 	(__raw_get_cpu_var(rt_cache_stat).field++)
 
-static int rt_intern_hash(unsigned hash, struct rtable *rth,
-				struct rtable **res);
-
 static unsigned int rt_hash_code(u32 daddr, u32 saddr)
 {
-	return (jhash_2words(daddr, saddr, rt_hash_rnd)
-		& rt_hash_mask);
+	return jhash_2words(daddr, saddr, atomic_read(&rt_genid))
+		& rt_hash_mask;
 }
 
 #define rt_hash(daddr, saddr, idx) \
@@ -282,27 +274,28 @@ static unsigned int rt_hash_code(u32 daddr, u32 saddr)
 #ifdef CONFIG_PROC_FS
 struct rt_cache_iter_state {
 	int bucket;
+	int genid;
 };
 
-static struct rtable *rt_cache_get_first(struct seq_file *seq)
+static struct rtable *rt_cache_get_first(struct rt_cache_iter_state *st)
 {
 	struct rtable *r = NULL;
-	struct rt_cache_iter_state *st = seq->private;
 
 	for (st->bucket = rt_hash_mask; st->bucket >= 0; --st->bucket) {
 		rcu_read_lock_bh();
-		r = rt_hash_table[st->bucket].chain;
-		if (r)
-			break;
+		r = rcu_dereference(rt_hash_table[st->bucket].chain);
+		while (r) {
+			if (r->rt_genid == st->genid)
+				return r;
+			r = rcu_dereference(r->u.dst.rt_next);
+		}
 		rcu_read_unlock_bh();
 	}
-	return rcu_dereference(r);
+	return r;
 }
 
-static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
+static struct rtable *rt_cache_get_next(struct rt_cache_iter_state *st, struct rtable *r)
 {
-	struct rt_cache_iter_state *st = seq->private;
-
 	r = r->u.dst.rt_next;
 	while (!r) {
 		rcu_read_unlock_bh();
@@ -314,29 +307,38 @@ static struct rtable *rt_cache_get_next(struct seq_file *seq, struct rtable *r)
 	return rcu_dereference(r);
 }
 
-static struct rtable *rt_cache_get_idx(struct seq_file *seq, loff_t pos)
+static struct rtable *rt_cache_get_idx(struct rt_cache_iter_state *st, loff_t pos)
 {
-	struct rtable *r = rt_cache_get_first(seq);
+	struct rtable *r = rt_cache_get_first(st);
 
 	if (r)
-		while (pos && (r = rt_cache_get_next(seq, r)))
+		while (pos && (r = rt_cache_get_next(st, r))) {
+			if (r->rt_genid != st->genid)
+				continue;
 			--pos;
+		}
 	return pos ? NULL : r;
 }
 
 static void *rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
 {
-	return *pos ? rt_cache_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
+	struct rt_cache_iter_state *st = seq->private;
+
+	if (*pos)
+		return rt_cache_get_idx(st, *pos - 1);
+	st->genid = atomic_read(&rt_genid);
+	return SEQ_START_TOKEN;
 }
 
 static void *rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-	struct rtable *r = NULL;
+	struct rtable *r;
+	struct rt_cache_iter_state *st = seq->private;
 
 	if (v == SEQ_START_TOKEN)
-		r = rt_cache_get_first(seq);
+		r = rt_cache_get_first(st);
 	else
-		r = rt_cache_get_next(seq, v);
+		r = rt_cache_get_next(st, v);
 	++*pos;
 	return r;
 }
@@ -709,6 +711,11 @@ static void rt_check_expire(void)
 			continue;
 		spin_lock_bh(rt_hash_lock_addr(i));
 		while ((rth = *rthp) != NULL) {
+			if (rth->rt_genid != atomic_read(&rt_genid)) {
+				*rthp = rth->u.dst.rt_next;
+				rt_free(rth);
+				continue;
+			}
 			if (rth->u.dst.expires) {
 				/* Entry is expired even if it is in use */
 				if (time_before_eq(jiffies, rth->u.dst.expires)) {
@@ -733,83 +740,45 @@ static void rt_check_expire(void)
 
 /*
  * rt_worker_func() is run in process context.
- * If a whole flush was scheduled, it is done.
- * Else, we call rt_check_expire() to scan part of the hash table
+ * we call rt_check_expire() to scan part of the hash table
  */
 static void rt_worker_func(struct work_struct *work)
 {
-	if (ip_rt_flush_expected) {
-		ip_rt_flush_expected = 0;
-		rt_do_flush(1);
-	} else
-		rt_check_expire();
+	rt_check_expire();
 	schedule_delayed_work(&expires_work, ip_rt_gc_interval);
 }
 
-/* This can run from both BH and non-BH contexts, the latter
- * in the case of a forced flush event.
+/*
+ * Pertubation of rt_genid by a small quantity [1..256]
+ * Using 8 bits of shuffling ensure we can call rt_cache_invalidate()
+ * many times (2^24) without giving recent rt_genid.
+ * Jenkins hash is strong enough that litle changes of rt_genid are OK.
  */
-static void rt_run_flush(unsigned long process_context)
+static void rt_cache_invalidate(void)
 {
-	rt_deadline = 0;
-
-	get_random_bytes(&rt_hash_rnd, 4);
+	unsigned char shuffle;
 
-	rt_do_flush(process_context);
+	get_random_bytes(&shuffle, sizeof(shuffle));
+	atomic_add(shuffle + 1U, &rt_genid);
 }
 
-static DEFINE_SPINLOCK(rt_flush_lock);
-
+/*
+ * delay < 0  : invalidate cache (fast : entries will be deleted later)
+ * delay >= 0 : invalidate & flush cache (can be long)
+ */
 void rt_cache_flush(int delay)
 {
-	unsigned long now = jiffies;
-	int user_mode = !in_softirq();
-
-	if (delay < 0)
-		delay = ip_rt_min_delay;
-
-	spin_lock_bh(&rt_flush_lock);
-
-	if (del_timer(&rt_flush_timer) && delay > 0 && rt_deadline) {
-		long tmo = (long)(rt_deadline - now);
-
-		/* If flush timer is already running
-		   and flush request is not immediate (delay > 0):
-
-		   if deadline is not achieved, prolongate timer to "delay",
-		   otherwise fire it at deadline time.
-		 */
-
-		if (user_mode && tmo < ip_rt_max_delay-ip_rt_min_delay)
-			tmo = 0;
-
-		if (delay > tmo)
-			delay = tmo;
-	}
-
-	if (delay <= 0) {
-		spin_unlock_bh(&rt_flush_lock);
-		rt_run_flush(user_mode);
-		return;
-	}
-
-	if (rt_deadline == 0)
-		rt_deadline = now + ip_rt_max_delay;
-
-	mod_timer(&rt_flush_timer, now+delay);
-	spin_unlock_bh(&rt_flush_lock);
+	rt_cache_invalidate();
+	if (delay >= 0)
+		rt_do_flush(!in_softirq());
 }
 
 /*
- * We change rt_hash_rnd and ask next rt_worker_func() invocation
- * to perform a flush in process context
+ * We change rt_genid and let gc do the cleanup
  */
 static void rt_secret_rebuild(unsigned long dummy)
 {
-	get_random_bytes(&rt_hash_rnd, 4);
-	ip_rt_flush_expected = 1;
-	cancel_delayed_work(&expires_work);
-	schedule_delayed_work(&expires_work, HZ/10);
+	rt_cache_invalidate();
 	mod_timer(&rt_secret_timer, jiffies + ip_rt_secret_interval);
 }
 
@@ -886,7 +855,8 @@ static int rt_garbage_collect(struct dst_ops *ops)
 			rthp = &rt_hash_table[k].chain;
 			spin_lock_bh(rt_hash_lock_addr(k));
 			while ((rth = *rthp) != NULL) {
-				if (!rt_may_expire(rth, tmo, expire)) {
+				if (rth->rt_genid == atomic_read(&rt_genid) &&
+					!rt_may_expire(rth, tmo, expire)) {
 					tmo >>= 1;
 					rthp = &rth->u.dst.rt_next;
 					continue;
@@ -967,6 +937,11 @@ restart:
 
 	spin_lock_bh(rt_hash_lock_addr(hash));
 	while ((rth = *rthp) != NULL) {
+		if (rth->rt_genid != atomic_read(&rt_genid)) {
+			*rthp = rth->u.dst.rt_next;
+			rt_free(rth);
+			continue;
+		}
 		if (compare_keys(&rth->fl, &rt->fl) && compare_netns(rth, rt)) {
 			/* Put it first */
 			*rthp = rth->u.dst.rt_next;
@@ -1132,17 +1107,19 @@ void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more)
 
 static void rt_del(unsigned hash, struct rtable *rt)
 {
-	struct rtable **rthp;
+	struct rtable **rthp, *aux;
 
+	rthp = &rt_hash_table[hash].chain;
 	spin_lock_bh(rt_hash_lock_addr(hash));
 	ip_rt_put(rt);
-	for (rthp = &rt_hash_table[hash].chain; *rthp;
-	     rthp = &(*rthp)->u.dst.rt_next)
-		if (*rthp == rt) {
-			*rthp = rt->u.dst.rt_next;
-			rt_free(rt);
-			break;
+	while ((aux = *rthp) != NULL) {
+		if (aux == rt || (aux->rt_genid != atomic_read(&rt_genid))) {
+			*rthp = aux->u.dst.rt_next;
+			rt_free(aux);
+			continue;
 		}
+		rthp = &aux->u.dst.rt_next;
+	}
 	spin_unlock_bh(rt_hash_lock_addr(hash));
 }
 
@@ -1187,7 +1164,8 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 				if (rth->fl.fl4_dst != daddr ||
 				    rth->fl.fl4_src != skeys[i] ||
 				    rth->fl.oif != ikeys[k] ||
-				    rth->fl.iif != 0) {
+				    rth->fl.iif != 0 ||
+				    rth->rt_genid != atomic_read(&rt_genid)) {
 					rthp = &rth->u.dst.rt_next;
 					continue;
 				}
@@ -1225,7 +1203,7 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
 				rt->u.dst.neighbour	= NULL;
 				rt->u.dst.hh		= NULL;
 				rt->u.dst.xfrm		= NULL;
-
+				rt->rt_genid		= atomic_read(&rt_genid);
 				rt->rt_flags		|= RTCF_REDIRECTED;
 
 				/* Gateway is different ... */
@@ -1446,7 +1424,8 @@ unsigned short ip_rt_frag_needed(struct net *net, struct iphdr *iph,
 			    rth->rt_src  == iph->saddr &&
 			    rth->fl.iif == 0 &&
 			    !(dst_metric_locked(&rth->u.dst, RTAX_MTU)) &&
-			    rth->u.dst.dev->nd_net == net) {
+			    rth->u.dst.dev->nd_net == net &&
+			    rth->rt_genid == atomic_read(&rt_genid)) {
 				unsigned short mtu = new_mtu;
 
 				if (new_mtu < 68 || new_mtu >= old_mtu) {
@@ -1681,8 +1660,9 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	rth->fl.oif	= 0;
 	rth->rt_gateway	= daddr;
 	rth->rt_spec_dst= spec_dst;
-	rth->rt_type	= RTN_MULTICAST;
+	rth->rt_genid	= atomic_read(&rt_genid);
 	rth->rt_flags	= RTCF_MULTICAST;
+	rth->rt_type	= RTN_MULTICAST;
 	if (our) {
 		rth->u.dst.input= ip_local_deliver;
 		rth->rt_flags |= RTCF_LOCAL;
@@ -1821,6 +1801,7 @@ static inline int __mkroute_input(struct sk_buff *skb,
 
 	rth->u.dst.input = ip_forward;
 	rth->u.dst.output = ip_output;
+	rth->rt_genid = atomic_read(&rt_genid);
 
 	rt_set_nexthop(rth, res, itag);
 
@@ -1981,6 +1962,7 @@ local_input:
 		goto e_nobufs;
 
 	rth->u.dst.output= ip_rt_bug;
+	rth->rt_genid = atomic_read(&rt_genid);
 
 	atomic_set(&rth->u.dst.__refcnt, 1);
 	rth->u.dst.flags= DST_HOST;
@@ -2072,7 +2054,8 @@ int ip_route_input(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 		    rth->fl.oif == 0 &&
 		    rth->fl.mark == skb->mark &&
 		    rth->fl.fl4_tos == tos &&
-		    rth->u.dst.dev->nd_net == net) {
+		    rth->u.dst.dev->nd_net == net &&
+		    rth->rt_genid == atomic_read(&rt_genid)) {
 			dst_use(&rth->u.dst, jiffies);
 			RT_CACHE_STAT_INC(in_hit);
 			rcu_read_unlock();
@@ -2200,6 +2183,7 @@ static inline int __mkroute_output(struct rtable **result,
 	rth->rt_spec_dst= fl->fl4_src;
 
 	rth->u.dst.output=ip_output;
+	rth->rt_genid = atomic_read(&rt_genid);
 
 	RT_CACHE_STAT_INC(out_slow_tot);
 
@@ -2472,7 +2456,8 @@ int __ip_route_output_key(struct net *net, struct rtable **rp,
 		    rth->fl.mark == flp->mark &&
 		    !((rth->fl.fl4_tos ^ flp->fl4_tos) &
 			    (IPTOS_RT_MASK | RTO_ONLINK)) &&
-		    rth->u.dst.dev->nd_net == net) {
+		    rth->u.dst.dev->nd_net == net &&
+		    rth->rt_genid == atomic_read(&rt_genid)) {
 			dst_use(&rth->u.dst, jiffies);
 			RT_CACHE_STAT_INC(out_hit);
 			rcu_read_unlock_bh();
@@ -2527,6 +2512,7 @@ static int ipv4_dst_blackhole(struct rtable **rp, struct flowi *flp, struct sock
 		rt->idev = ort->idev;
 		if (rt->idev)
 			in_dev_hold(rt->idev);
+		rt->rt_genid = atomic_read(&rt_genid);
 		rt->rt_flags = ort->rt_flags;
 		rt->rt_type = ort->rt_type;
 		rt->rt_dst = ort->rt_dst;
@@ -2781,6 +2767,8 @@ int ip_rt_dump(struct sk_buff *skb,  struct netlink_callback *cb)
 		     rt = rcu_dereference(rt->u.dst.rt_next), idx++) {
 			if (idx < s_idx)
 				continue;
+			if (rt->rt_genid != atomic_read(&rt_genid))
+				continue;
 			skb->dst = dst_clone(&rt->u.dst);
 			if (rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
 					 cb->nlh->nlmsg_seq, RTM_NEWROUTE,
@@ -2850,24 +2838,6 @@ ctl_table ipv4_route_table[] = {
 		.strategy	= &ipv4_sysctl_rtcache_flush_strategy,
 	},
 	{
-		.ctl_name	= NET_IPV4_ROUTE_MIN_DELAY,
-		.procname	= "min_delay",
-		.data		= &ip_rt_min_delay,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_jiffies,
-		.strategy	= &sysctl_jiffies,
-	},
-	{
-		.ctl_name	= NET_IPV4_ROUTE_MAX_DELAY,
-		.procname	= "max_delay",
-		.data		= &ip_rt_max_delay,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec_jiffies,
-		.strategy	= &sysctl_jiffies,
-	},
-	{
 		.ctl_name	= NET_IPV4_ROUTE_GC_THRESH,
 		.procname	= "gc_thresh",
 		.data		= &ipv4_dst_ops.gc_thresh,
@@ -3025,8 +2995,8 @@ int __init ip_rt_init(void)
 {
 	int rc = 0;
 
-	rt_hash_rnd = (int) ((num_physpages ^ (num_physpages>>8)) ^
-			     (jiffies ^ (jiffies >> 7)));
+	atomic_set(&rt_genid, (int) ((num_physpages ^ (num_physpages>>8)) ^
+			     (jiffies ^ (jiffies >> 7))));
 
 #ifdef CONFIG_NET_CLS_ROUTE
 	ip_rt_acct = __alloc_percpu(256 * sizeof(struct ip_rt_acct));
@@ -3059,7 +3029,6 @@ int __init ip_rt_init(void)
 	devinet_init();
 	ip_fib_init();
 
-	setup_timer(&rt_flush_timer, rt_run_flush, 0);
 	setup_timer(&rt_secret_timer, rt_secret_rebuild, 0);
 
 	/* All the timers, started at system startup tend