[IPV6]: ROUTE: Clean-up cow'ing in ip6_route_{intput,output}().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 60 insertions, 53 deletions

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 061a7bba163a..6a4019a4ca89 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -72,6 +72,7 @@
 #define RT6_TRACE(x...) do { ; } while (0)
 #endif
 
+#define CLONE_OFFLINK_ROUTE 0
 
 static int ip6_rt_max_size = 4096;
 static int ip6_rt_gc_min_interval = HZ / 2;
@@ -465,9 +466,10 @@ if (rt == &ip6_null_entry && strict) { \
 void ip6_route_input(struct sk_buff *skb)
 {
         struct fib6_node *fn;
-        struct rt6_info *rt;
+        struct rt6_info *rt, *nrt;
         int strict;
         int attempts = 3;
+        int err;
 
         strict = ipv6_addr_type(&skb->nh.ipv6h->daddr) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL);
 
@@ -492,51 +494,53 @@ restart:
         dst_hold(&rt->u.dst);
         read_unlock_bh(&rt6_lock);
 
-        if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP)) {
-                struct rt6_info *nrt;
-                int err;
-
-                nrt = rt6_alloc_cow(rt, &skb->nh.ipv6h->daddr,
-                                    &skb->nh.ipv6h->saddr);
-
-                dst_release(&rt->u.dst);
-                rt = nrt ? : &ip6_null_entry;
+        if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
+                nrt = rt6_alloc_cow(rt, &skb->nh.ipv6h->daddr, &skb->nh.ipv6h->saddr);
+        else {
+#if CLONE_OFFLINK_ROUTE
+                nrt = rt6_alloc_clone(rt, &skb->nh.ipv6h->daddr);
+#else
+                goto out2;
+#endif
+        }
 
-                dst_hold(&rt->u.dst);
-                if (nrt) {
-                        err = ip6_ins_rt(nrt, NULL, NULL,
-                                         &NETLINK_CB(skb));
-                        if (!err)
-                                goto out2;
-                }
+        dst_release(&rt->u.dst);
+        rt = nrt ? : &ip6_null_entry;
 
-                if (--attempts <= 0)
+        dst_hold(&rt->u.dst);
+        if (nrt) {
+                err = ip6_ins_rt(nrt, NULL, NULL, &NETLINK_CB(skb));
+                if (!err)
                         goto out2;
-
-                /* Race condition! In the gap, when rt6_lock was
-                   released someone could insert this route.  Relookup.
-                */
-                dst_release(&rt->u.dst);
-                goto relookup;
         }
 
+        if (--attempts <= 0)
+                goto out2;
+
+        /*
+         * Race condition! In the gap, when rt6_lock was
+         * released someone could insert this route.  Relookup.
+         */
+        dst_release(&rt->u.dst);
+        goto relookup;
+
+out:
+        dst_hold(&rt->u.dst);
+        read_unlock_bh(&rt6_lock);
 out2:
         rt->u.dst.lastuse = jiffies;
         rt->u.dst.__use++;
         skb->dst = (struct dst_entry *) rt;
         return;
-out:
-        dst_hold(&rt->u.dst);
-        read_unlock_bh(&rt6_lock);
-        goto out2;
 }
 
 struct dst_entry * ip6_route_output(struct sock *sk, struct flowi *fl)
 {
         struct fib6_node *fn;
-        struct rt6_info *rt;
+        struct rt6_info *rt, *nrt;
         int strict;
         int attempts = 3;
+        int err;
 
         strict = ipv6_addr_type(&fl->fl6_dst) & (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL);
 
@@ -564,40 +568,43 @@ restart:
         dst_hold(&rt->u.dst);
         read_unlock_bh(&rt6_lock);
 
-        if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP)) {
-                struct rt6_info *nrt;
-                int err;
-
+        if (!rt->rt6i_nexthop && !(rt->rt6i_flags & RTF_NONEXTHOP))
                 nrt = rt6_alloc_cow(rt, &fl->fl6_dst, &fl->fl6_src);
+        else {
+#if CLONE_OFFLINK_ROUTE
+                nrt = rt6_alloc_clone(rt, &fl->fl6_dst);
+#else
+                goto out2;
+#endif
+        }
 
-                dst_release(&rt->u.dst);
-                rt = nrt ? : &ip6_null_entry;
-
-                dst_hold(&rt->u.dst);
-                if (nrt) {
-                        err = ip6_ins_rt(nrt, NULL, NULL, NULL);
-                        if (!err)
-                                goto out2;
-                }
+        dst_release(&rt->u.dst);
+        rt = nrt ? : &ip6_null_entry;
 
-                if (--attempts <= 0)
+        dst_hold(&rt->u.dst);
+        if (nrt) {
+                err = ip6_ins_rt(nrt, NULL, NULL, NULL);
+                if (!err)
                         goto out2;
-
-                /* Race condition! In the gap, when rt6_lock was
-                   released someone could insert this route.  Relookup.
-                */
-                dst_release(&rt->u.dst);
-                goto relookup;
         }
 
+        if (--attempts <= 0)
+                goto out2;
+
+        /*
+         * Race condition! In the gap, when rt6_lock was
+         * released someone could insert this route.  Relookup.
+         */
+        dst_release(&rt->u.dst);
+        goto relookup;
+
+out:
+        dst_hold(&rt->u.dst);
+        read_unlock_bh(&rt6_lock);
 out2:
         rt->u.dst.lastuse = jiffies;
         rt->u.dst.__use++;
         return &rt->u.dst;
-out:
-        dst_hold(&rt->u.dst);
-        read_unlock_bh(&rt6_lock);
-        goto out2;
 }