[IPV4] fib_trie: avoid extra search on delete

Get rid of extra search that made route deletion O(n).

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 38 deletions

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 2ea94ebe19f8..441c4eafb9e0 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1545,49 +1545,23 @@ found:
         return ret;
 }
 
-/* only called from updater side */
-static int trie_leaf_remove(struct trie *t, t_key key)
+/*
+ * Remove the leaf and return parent.
+ */
+static void trie_leaf_remove(struct trie *t, struct leaf *l)
 {
-        t_key cindex;
-        struct tnode *tp = NULL;
-        struct node *n = t->trie;
-        struct leaf *l;
-
-        pr_debug("entering trie_leaf_remove(%p)\n", n);
+        struct tnode *tp = node_parent((struct node *) l);
 
-        /* Note that in the case skipped bits, those bits are *not* checked!
-         * When we finish this, we will have NULL or a T_LEAF, and the
-         * T_LEAF may or may not match our key.
-         */
-
-        while (n != NULL && IS_TNODE(n)) {
-                struct tnode *tn = (struct tnode *) n;
-                check_tnode(tn);
-                n = tnode_get_child(tn, tkey_extract_bits(key,
-                                                          tn->pos, tn->bits));
-
-                BUG_ON(n && node_parent(n) != tn);
-        }
-        l = (struct leaf *) n;
-
-        if (!n || !tkey_equals(l->key, key))
-                return 0;
-
-        /*
-         * Key found.
-         * Remove the leaf and rebalance the tree
-         */
-        tp = node_parent(n);
-        tnode_free((struct tnode *) n);
+        pr_debug("entering trie_leaf_remove(%p)\n", l);
 
         if (tp) {
-                cindex = tkey_extract_bits(key, tp->pos, tp->bits);
+                t_key cindex = tkey_extract_bits(l->key, tp->pos, tp->bits);
                 put_child(t, (struct tnode *)tp, cindex, NULL);
                 rcu_assign_pointer(t->trie, trie_rebalance(t, tp));
         } else
                 rcu_assign_pointer(t->trie, NULL);
 
-        return 1;
+        tnode_free((struct tnode *) l);
 }
 
 /*
@@ -1665,7 +1639,7 @@ static int fn_trie_delete(struct fib_table *tb, struct fib_config *cfg)
         }
 
         if (hlist_empty(&l->list))
-                trie_leaf_remove(t, key);
+                trie_leaf_remove(t, l);
 
         if (fa->fa_state & FA_S_ACCESSED)
                 rt_cache_flush(-1);
@@ -1778,19 +1752,19 @@ static struct leaf *trie_nextleaf(struct leaf *l)
 static int fn_trie_flush(struct fib_table *tb)
 {
         struct trie *t = (struct trie *) tb->tb_data;
-        struct leaf *ll = NULL, *l = NULL;
+        struct leaf *l, *ll = NULL;
         int found = 0;
 
         for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {
                 found += trie_flush_leaf(t, l);
 
                 if (ll && hlist_empty(&ll->list))
-                        trie_leaf_remove(t, ll->key);
+                        trie_leaf_remove(t, ll);
                 ll = l;
         }
 
         if (ll && hlist_empty(&ll->list))
-                trie_leaf_remove(t, ll->key);
+                trie_leaf_remove(t, ll);
 
         pr_debug("trie_flush found=%d\n", found);
         return found;