ipv4: Cache routes in nexthop exception entries.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index e331746..926142e 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -55,6 +55,7 @@ struct fib_nh_exception {
        u32                             fnhe_pmtu;
        __be32                          fnhe_gw;
        unsigned long                   fnhe_expires;
+       struct rtable __rcu             *fnhe_rth;
        unsigned long                   fnhe_stamp;
 };
 

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index fe2ca02..da80dc1 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -140,6 +140,21 @@ const struct fib_prop fib_props[RTN_MAX + 1] = {
        },
 };
 
+static void rt_fibinfo_free(struct rtable __rcu **rtp)
+{
+       struct rtable *rt = rcu_dereference_protected(*rtp, 1);
+
+       if (!rt)
+               return;
+
+       /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
+        * because we waited an RCU grace period before calling
+        * free_fib_info_rcu()
+        */
+
+       dst_free(&rt->dst);
+}
+
 static void free_nh_exceptions(struct fib_nh *nh)
 {
        struct fnhe_hash_bucket *hash = nh->nh_exceptions;
@@ -153,6 +168,9 @@ static void free_nh_exceptions(struct fib_nh *nh)
                        struct fib_nh_exception *next;
                        
                        next = rcu_dereference_protected(fnhe->fnhe_next, 1);
+
+                       rt_fibinfo_free(&fnhe->fnhe_rth);
+
                        kfree(fnhe);
 
                        fnhe = next;
@@ -161,22 +179,7 @@ static void free_nh_exceptions(struct fib_nh *nh)
        kfree(hash);
 }
 
-static void rt_nexthop_free(struct rtable __rcu **rtp)
-{
-       struct rtable *rt = rcu_dereference_protected(*rtp, 1);
-
-       if (!rt)
-               return;
-
-       /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
-        * because we waited an RCU grace period before calling
-        * free_fib_info_rcu()
-        */
-
-       dst_free(&rt->dst);
-}
-
-static void rt_nexthop_free_cpus(struct rtable __rcu * __percpu *rtp)
+static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 {
        int cpu;
 
@@ -203,8 +206,8 @@ static void free_fib_info_rcu(struct rcu_head *head)
                        dev_put(nexthop_nh->nh_dev);
                if (nexthop_nh->nh_exceptions)
                        free_nh_exceptions(nexthop_nh);
-               rt_nexthop_free_cpus(nexthop_nh->nh_pcpu_rth_output);
-               rt_nexthop_free(&nexthop_nh->nh_rth_input);
+               rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
+               rt_fibinfo_free(&nexthop_nh->nh_rth_input);
        } endfor_nexthops(fi);
 
        release_net(fi->fib_net);

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 4f6276c..b102eeb 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -587,11 +587,17 @@ 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 +605,11 @@ 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 +631,7 @@ 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 +678,7 @@ 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;
 }
 
@@ -1167,41 +1178,40 @@ static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
 static void 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;
+       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;
                }
-       }
-       if (gw) {
-               rt->rt_flags |= RTCF_REDIRECTED;
-               rt->rt_gateway = gw;
-       }
-       fnhe->fnhe_stamp = jiffies;
-}
 
-static inline void rt_free(struct rtable *rt)
-{
-       call_rcu(&rt->dst.rcu_head, dst_rcu_free);
+               orig = rcu_dereference(fnhe->fnhe_rth);
+               rcu_assign_pointer(fnhe->fnhe_rth, rt);
+               if (orig)
+                       rt_free(orig);
+
+               fnhe->fnhe_stamp = jiffies;
+       } 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;
+       }
+       spin_unlock_bh(&fnhe_lock);
 }
 
 static void rt_cache_route(struct fib_nh *nh, struct rtable *rt)
@@ -1249,13 +1259,13 @@ static void rt_set_nexthop(struct rtable *rt, __be32 daddr,
 
                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))
+               if (unlikely(fnhe))
+                       rt_bind_exception(rt, fnhe, daddr);
+               else if (!(rt->dst.flags & DST_NOCACHE))
                        rt_cache_route(nh, rt);
        }
 
@@ -1753,22 +1763,23 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
 
        fnhe = NULL;
        if (fi) {
-               fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
-               if (!fnhe && FIB_RES_NH(*res).nh_pcpu_rth_output) {
-                       struct rtable __rcu **prth;
+               struct rtable __rcu **prth;
 
+               fnhe = find_exception(&FIB_RES_NH(*res), fl4->daddr);
+               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 = 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);