[IPV6] ROUTE: Make sure we have fn->leaf when adding a node on subtree.

Based on MIPL2 kernel patch.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Ville Nuorvala <vnuorval@tcs.hut.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 6 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 667b1b1ea25d..11f9660a4796 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -80,6 +80,7 @@ static DEFINE_RWLOCK(fib6_walker_lock);
 #endif
 
 static void fib6_prune_clones(struct fib6_node *fn, struct rt6_info *rt);
+static struct rt6_info * fib6_find_prefix(struct fib6_node *fn);
 static struct fib6_node * fib6_repair_tree(struct fib6_node *fn);
 static int fib6_walk(struct fib6_walker_t *w);
 static int fib6_walk_continue(struct fib6_walker_t *w);
@@ -697,7 +698,7 @@ void fib6_force_start_gc(void)
 
 int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
 {
-        struct fib6_node *fn;
+        struct fib6_node *fn, *pn = NULL;
         int err = -ENOMEM;
 
         fn = fib6_add_1(root, &rt->rt6i_dst.addr, sizeof(struct in6_addr),
@@ -706,6 +707,8 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
         if (fn == NULL)
                 goto out;
 
+        pn = fn;
+
 #ifdef CONFIG_IPV6_SUBTREES
         if (rt->rt6i_src.plen) {
                 struct fib6_node *sn;
@@ -751,10 +754,6 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
                         /* Now link new subtree to main tree */
                         sfn->parent = fn;
                         fn->subtree = sfn;
-                        if (fn->leaf == NULL) {
-                                fn->leaf = rt;
-                                atomic_inc(&rt->rt6i_ref);
-                        }
                 } else {
                         sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
                                         sizeof(struct in6_addr), rt->rt6i_src.plen,
@@ -764,6 +763,10 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
                                 goto st_failure;
                 }
 
+                if (fn->leaf == NULL) {
+                        fn->leaf = rt;
+                        atomic_inc(&rt->rt6i_ref);
+                }
                 fn = sn;
         }
 #endif
@@ -777,8 +780,25 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info)
         }
 
 out:
-        if (err)
+        if (err) {
+#ifdef CONFIG_IPV6_SUBTREES
+                /*
+                 * If fib6_add_1 has cleared the old leaf pointer in the
+                 * super-tree leaf node we have to find a new one for it.
+                 */
+                if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) {
+                        pn->leaf = fib6_find_prefix(pn);
+#if RT6_DEBUG >= 2
+                        if (!pn->leaf) {
+                                BUG_TRAP(pn->leaf != NULL);
+                                pn->leaf = &ip6_null_entry;
+                        }
+#endif
+                        atomic_inc(&pn->leaf->rt6i_ref);
+                }
+#endif
                 dst_free(&rt->u.dst);
+        }
         return err;
 
 #ifdef CONFIG_IPV6_SUBTREES