ipv6: don't walk node's leaf during serial number update

Cc: YOSHIFUJI Hideaki <hideaki@yoshifuji.org>
Cc: Martin Lau <kafai@fb.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 30 insertions, 17 deletions

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 6f9beb1f2861..b2d1838897c9 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -50,6 +50,7 @@ struct fib6_cleaner {
         struct fib6_walker w;
         struct net *net;
         int (*func)(struct rt6_info *, void *arg);
+        int sernum;
         void *arg;
 };
 
@@ -105,6 +106,10 @@ static int fib6_new_sernum(struct net *net)
         return new;
 }
 
+enum {
+        FIB6_NO_SERNUM_CHANGE = 0,
+};
+
 /*
  *      Auxiliary address test functions for the radix tree.
  *
@@ -1514,6 +1519,16 @@ static int fib6_clean_node(struct fib6_walker *w)
                 .nl_net = c->net,
         };
 
+        if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
+            w->node->fn_sernum != c->sernum)
+                w->node->fn_sernum = c->sernum;
+
+        if (!c->func) {
+                WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
+                w->leaf = NULL;
+                return 0;
+        }
+
         for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
                 res = c->func(rt, c->arg);
                 if (res < 0) {
@@ -1547,7 +1562,7 @@ static int fib6_clean_node(struct fib6_walker *w)
 
 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
                             int (*func)(struct rt6_info *, void *arg),
-                            bool prune, void *arg)
+                            bool prune, int sernum, void *arg)
 {
         struct fib6_cleaner c;
 
@@ -1557,14 +1572,16 @@ static void fib6_clean_tree(struct net *net, struct fib6_node *root,
         c.w.count = 0;
         c.w.skip = 0;
         c.func = func;
+        c.sernum = sernum;
         c.arg = arg;
         c.net = net;
 
         fib6_walk(&c.w);
 }
 
-void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
-                    void *arg)
+static void __fib6_clean_all(struct net *net,
+                             int (*func)(struct rt6_info *, void *),
+                             int sernum, void *arg)
 {
         struct fib6_table *table;
         struct hlist_head *head;
@@ -1576,13 +1593,19 @@ void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
                 hlist_for_each_entry_rcu(table, head, tb6_hlist) {
                         write_lock_bh(&table->tb6_lock);
                         fib6_clean_tree(net, &table->tb6_root,
-                                        func, false, arg);
+                                        func, false, sernum, arg);
                         write_unlock_bh(&table->tb6_lock);
                 }
         }
         rcu_read_unlock();
 }
 
+void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
+                    void *arg)
+{
+        __fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
+}
+
 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
 {
         if (rt->rt6i_flags & RTF_CACHE) {
@@ -1595,25 +1618,15 @@ static int fib6_prune_clone(struct rt6_info *rt, void *arg)
 
 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
 {
-        fib6_clean_tree(net, fn, fib6_prune_clone, true, NULL);
-}
-
-static int fib6_update_sernum(struct rt6_info *rt, void *arg)
-{
-        int sernum = *(int *)arg;
-
-        if (rt->rt6i_node &&
-            rt->rt6i_node->fn_sernum != sernum)
-                rt->rt6i_node->fn_sernum = sernum;
-
-        return 0;
+        fib6_clean_tree(net, fn, fib6_prune_clone, true,
+                        FIB6_NO_SERNUM_CHANGE, NULL);
 }
 
 static void fib6_flush_trees(struct net *net)
 {
         int new_sernum = fib6_new_sernum(net);
 
-        fib6_clean_all(net, fib6_update_sernum, &new_sernum);
+        __fib6_clean_all(net, NULL, new_sernum, NULL);
 }
 
 /*