1 files changed, 131 insertions, 52 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index fc1a81ca79a7..c035251beb07 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -147,6 +147,7 @@ static void		 ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
                                            struct sk_buff *skb, u32 mtu);
 static void              ip_do_redirect(struct dst_entry *dst, struct sock *sk,
                                         struct sk_buff *skb);
+static void             ipv4_dst_destroy(struct dst_entry *dst);
 
 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
                             int how)
@@ -170,6 +171,7 @@ static struct dst_ops ipv4_dst_ops = {
         .default_advmss =       ipv4_default_advmss,
         .mtu =                  ipv4_mtu,
         .cow_metrics =          ipv4_cow_metrics,
+        .destroy =              ipv4_dst_destroy,
         .ifdown =               ipv4_dst_ifdown,
         .negative_advice =      ipv4_negative_advice,
         .link_failure =         ipv4_link_failure,
@@ -587,11 +589,17 @@ static void ip_rt_build_flow_key(struct flowi4 *fl4, const struct sock *sk,
                 build_sk_flow_key(fl4, sk);
 }
 
-static DEFINE_SEQLOCK(fnhe_seqlock);
+static inline void rt_free(struct rtable *rt)
+{
+        call_rcu(&rt->dst.rcu_head, dst_rcu_free);
+}
+
+static DEFINE_SPINLOCK(fnhe_lock);
 
 static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
 {
         struct fib_nh_exception *fnhe, *oldest;
+        struct rtable *orig;
 
         oldest = rcu_dereference(hash->chain);
         for (fnhe = rcu_dereference(oldest->fnhe_next); fnhe;
@@ -599,6 +607,11 @@ static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
                 if (time_before(fnhe->fnhe_stamp, oldest->fnhe_stamp))
                         oldest = fnhe;
         }
+        orig = rcu_dereference(oldest->fnhe_rth);
+        if (orig) {
+                RCU_INIT_POINTER(oldest->fnhe_rth, NULL);
+                rt_free(orig);
+        }
         return oldest;
 }
 
@@ -620,7 +633,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
         int depth;
         u32 hval = fnhe_hashfun(daddr);
 
-        write_seqlock_bh(&fnhe_seqlock);
+        spin_lock_bh(&fnhe_lock);
 
         hash = nh->nh_exceptions;
         if (!hash) {
@@ -667,7 +680,7 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
         fnhe->fnhe_stamp = jiffies;
 
 out_unlock:
-        write_sequnlock_bh(&fnhe_seqlock);
+        spin_unlock_bh(&fnhe_lock);
         return;
 }
 
@@ -1164,53 +1177,62 @@ static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
         return NULL;
 }
 
-static void rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
+static bool rt_bind_exception(struct rtable *rt, struct fib_nh_exception *fnhe,
                               __be32 daddr)
 {
-        __be32 fnhe_daddr, gw;
-        unsigned long expires;
-        unsigned int seq;
-        u32 pmtu;
-
-restart:
-        seq = read_seqbegin(&fnhe_seqlock);
-        fnhe_daddr = fnhe->fnhe_daddr;
-        gw = fnhe->fnhe_gw;
-        pmtu = fnhe->fnhe_pmtu;
-        expires = fnhe->fnhe_expires;
-        if (read_seqretry(&fnhe_seqlock, seq))
-                goto restart;
-
-        if (daddr != fnhe_daddr)
-                return;
+        bool ret = false;
+
+        spin_lock_bh(&fnhe_lock);
 
-        if (pmtu) {
-                unsigned long diff = expires - jiffies;
+        if (daddr == fnhe->fnhe_daddr) {
+                struct rtable *orig;
 
-                if (time_before(jiffies, expires)) {
-                        rt->rt_pmtu = pmtu;
-                        dst_set_expires(&rt->dst, diff);
+                if (fnhe->fnhe_pmtu) {
+                        unsigned long expires = fnhe->fnhe_expires;
+                        unsigned long diff = expires - jiffies;
+
+                        if (time_before(jiffies, expires)) {
+                                rt->rt_pmtu = fnhe->fnhe_pmtu;
+                                dst_set_expires(&rt->dst, diff);
+                        }
                 }
+                if (fnhe->fnhe_gw) {
+                        rt->rt_flags |= RTCF_REDIRECTED;
+                        rt->rt_gateway = fnhe->fnhe_gw;
+                }
+
+                orig = rcu_dereference(fnhe->fnhe_rth);
+                rcu_assign_pointer(fnhe->fnhe_rth, rt);
+                if (orig)
+                        rt_free(orig);
+
+                fnhe->fnhe_stamp = jiffies;
+                ret = true;
+        } else {
+                /* Routes we intend to cache in nexthop exception have
+                 * the DST_NOCACHE bit clear.  However, if we are
+                 * unsuccessful at storing this route into the cache
+                 * we really need to set it.
+                 */
+                rt->dst.flags |= DST_NOCACHE;
         }
-        if (gw) {
-                rt->rt_flags |= RTCF_REDIRECTED;
-                rt->rt_gateway = gw;
-        }
-        fnhe->fnhe_stamp = jiffies;
-}
+        spin_unlock_bh(&fnhe_lock);
 
-static inline void rt_free(struct rtable *rt)
-{
-        call_rcu_bh(&rt->dst.rcu_head, dst_rcu_free);
+        return ret;
 }
 
-static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
+static bool rt_cache_route(struct fib_nh *nh, struct rtable *rt)
 {
-        struct rtable *orig, *prev, **p = &nh->nh_rth_output;
-
-        if (rt_is_input_route(rt))
-                p = &nh->nh_rth_input;
+        struct rtable *orig, *prev, **p;
+        bool ret = true;
 
+        if (rt_is_input_route(rt)) {
+                p = (struct rtable **)&nh->nh_rth_input;
+        } else {
+                if (!nh->nh_pcpu_rth_output)
+                        goto nocache;
+                p = (struct rtable **)__this_cpu_ptr(nh->nh_pcpu_rth_output);
+        }
         orig = *p;
 
         prev = cmpxchg(p, orig, rt);
@@ -1223,7 +1245,50 @@ static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
                  * unsuccessful at storing this route into the cache
                  * we really need to set it.
                  */
+nocache:
                 rt->dst.flags |= DST_NOCACHE;
+                ret = false;
+        }
+
+        return ret;
+}
+
+static DEFINE_SPINLOCK(rt_uncached_lock);
+static LIST_HEAD(rt_uncached_list);
+
+static void rt_add_uncached_list(struct rtable *rt)
+{
+        spin_lock_bh(&rt_uncached_lock);
+        list_add_tail(&rt->rt_uncached, &rt_uncached_list);
+        spin_unlock_bh(&rt_uncached_lock);
+}
+
+static void ipv4_dst_destroy(struct dst_entry *dst)
+{
+        struct rtable *rt = (struct rtable *) dst;
+
+        if (dst->flags & DST_NOCACHE) {
+                spin_lock_bh(&rt_uncached_lock);
+                list_del(&rt->rt_uncached);
+                spin_unlock_bh(&rt_uncached_lock);
+        }
+}
+
+void rt_flush_dev(struct net_device *dev)
+{
+        if (!list_empty(&rt_uncached_list)) {
+                struct net *net = dev_net(dev);
+                struct rtable *rt;
+
+                spin_lock_bh(&rt_uncached_lock);
+                list_for_each_entry(rt, &rt_uncached_list, rt_uncached) {
+                        if (rt->dst.dev != dev)
+                                continue;
+                        rt->dst.dev = net->loopback_dev;
+                        dev_hold(rt->dst.dev);
+                        dev_put(dev);
+                }
+                spin_unlock_bh(&rt_uncached_lock);
         }
 }
 
@@ -1239,20 +1304,24 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
                            struct fib_nh_exception *fnhe,
                            struct fib_info *fi, u16 type, u32 itag)
 {
+        bool cached = false;
+
         if (fi) {
                 struct fib_nh *nh = &FIB_RES_NH(*res);
 
                 if (nh->nh_gw && nh->nh_scope == RT_SCOPE_LINK)
                         rt->rt_gateway = nh->nh_gw;
-                if (unlikely(fnhe))
-                        rt_bind_exception(rt, fnhe, daddr);
                 dst_init_metrics(&rt->dst, fi->fib_metrics, true);
 #ifdef CONFIG_IP_ROUTE_CLASSID
                 rt->dst.tclassid = nh->nh_tclassid;
 #endif
-                if (!(rt->dst.flags & DST_NOCACHE))
-                        rt_cache_route(nh, rt);
+                if (unlikely(fnhe))
+                        cached = rt_bind_exception(rt, fnhe, daddr);
+                else if (!(rt->dst.flags & DST_NOCACHE))
+                        cached = rt_cache_route(nh, rt);
         }
+        if (unlikely(!cached))
+                rt_add_uncached_list(rt);
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
 #ifdef CONFIG_IP_MULTIPLE_TABLES
@@ -1319,6 +1388,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
         rth->rt_iif     = 0;
         rth->rt_pmtu    = 0;
         rth->rt_gateway = 0;
+        INIT_LIST_HEAD(&rth->rt_uncached);
         if (our) {
                 rth->dst.input= ip_local_deliver;
                 rth->rt_flags |= RTCF_LOCAL;
@@ -1420,7 +1490,7 @@ static int __mkroute_input(struct sk_buff *skb,
         do_cache = false;
         if (res->fi) {
                 if (!itag) {
-                        rth = FIB_RES_NH(*res).nh_rth_input;
+                        rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
                         if (rt_cache_valid(rth)) {
                                 skb_dst_set_noref(skb, &rth->dst);
                                 goto out;
@@ -1444,6 +1514,7 @@ static int __mkroute_input(struct sk_buff *skb,
         rth->rt_iif     = 0;
         rth->rt_pmtu    = 0;
         rth->rt_gateway = 0;
+        INIT_LIST_HEAD(&rth->rt_uncached);
 
         rth->dst.input = ip_forward;
         rth->dst.output = ip_output;
@@ -1582,7 +1653,7 @@ local_input:
         do_cache = false;
         if (res.fi) {
                 if (!itag) {
-                        rth = FIB_RES_NH(res).nh_rth_input;
+                        rth = rcu_dereference(FIB_RES_NH(res).nh_rth_input);
                         if (rt_cache_valid(rth)) {
                                 skb_dst_set_noref(skb, &rth->dst);
                                 err = 0;
@@ -1610,6 +1681,7 @@ local_input:
         rth->rt_iif     = 0;
         rth->rt_pmtu    = 0;
         rth->rt_gateway = 0;
+        INIT_LIST_HEAD(&rth->rt_uncached);
         if (res.type == RTN_UNREACHABLE) {
                 rth->dst.input= ip_error;
                 rth->dst.error= -err;
@@ -1748,19 +1820,23 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 
         fnhe = NULL;
         if (fi) {
+                struct rtable __rcu **prth;
+
                 fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
-                if (!fnhe) {
-                        rth = FIB_RES_NH(*res).nh_rth_output;
-                        if (rt_cache_valid(rth)) {
-                                dst_hold(&rth->dst);
-                                return rth;
-                        }
+                if (fnhe)
+                        prth = &fnhe->fnhe_rth;
+                else
+                        prth = __this_cpu_ptr(FIB_RES_NH(*res).nh_pcpu_rth_output);
+                rth = rcu_dereference(*prth);
+                if (rt_cache_valid(rth)) {
+                        dst_hold(&rth->dst);
+                        return rth;
                 }
         }
         rth = rt_dst_alloc(dev_out,
                            IN_DEV_CONF_GET(in_dev, NOPOLICY),
                            IN_DEV_CONF_GET(in_dev, NOXFRM),
-                           fi && !fnhe);
+                           fi);
         if (!rth)
                 return ERR_PTR(-ENOBUFS);
 
@@ -1773,6 +1849,7 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
         rth->rt_iif     = orig_oif ? : 0;
         rth->rt_pmtu    = 0;
         rth->rt_gateway = 0;
+        INIT_LIST_HEAD(&rth->rt_uncached);
 
         RT_CACHE_STAT_INC(out_slow_tot);
 
@@ -2052,6 +2129,8 @@ struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_or
                 rt->rt_type = ort->rt_type;
                 rt->rt_gateway = ort->rt_gateway;
 
+                INIT_LIST_HEAD(&rt->rt_uncached);
+
                 dst_free(new);
         }