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[IPV4] fib_trie: iterator recode
Remove the complex loop structure of nextleaf() and replace it with a simpler tree walker. This improves the performance and is much cleaner. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1711,64 +1711,65 @@ static int trie_flush_leaf(struct trie *t, struct leaf *l)
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return found;
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}
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/* rcu_read_lock needs to be hold by caller from readside */
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static struct leaf *nextleaf(struct trie *t, struct leaf *thisleaf)
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/*
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* Scan for the next right leaf starting at node p->child[idx]
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* Since we have back pointer, no recursion necessary.
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*/
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static struct leaf *leaf_walk_rcu(struct tnode *p, struct node *c)
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{
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struct node *c = (struct node *) thisleaf;
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struct tnode *p;
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int idx;
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struct node *trie = rcu_dereference(t->trie);
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do {
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t_key idx;
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if (c == NULL) {
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if (trie == NULL)
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return NULL;
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if (IS_LEAF(trie)) /* trie w. just a leaf */
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return (struct leaf *) trie;
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p = (struct tnode *)trie; /* Start */
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} else
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p = node_parent_rcu(c);
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while (p) {
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int pos, last;
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/* Find the next child of the parent */
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if (c)
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pos = 1 + tkey_extract_bits(c->key, p->pos, p->bits);
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idx = tkey_extract_bits(c->key, p->pos, p->bits) + 1;
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else
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pos = 0;
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last = 1 << p->bits;
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for (idx = pos; idx < last ; idx++) {
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c = rcu_dereference(p->child[idx]);
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idx = 0;
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while (idx < 1u << p->bits) {
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c = tnode_get_child_rcu(p, idx++);
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if (!c)
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continue;
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/* Decend if tnode */
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while (IS_TNODE(c)) {
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p = (struct tnode *) c;
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idx = 0;
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/* Rightmost non-NULL branch */
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if (p && IS_TNODE(p))
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while (!(c = rcu_dereference(p->child[idx]))
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&& idx < (1<<p->bits)) idx++;
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/* Done with this tnode? */
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if (idx >= (1 << p->bits) || !c)
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goto up;
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if (IS_LEAF(c)) {
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prefetch(p->child[idx]);
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return (struct leaf *) c;
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}
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return (struct leaf *) c;
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/* Rescan start scanning in new node */
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p = (struct tnode *) c;
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idx = 0;
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}
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up:
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/* No more children go up one step */
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/* Node empty, walk back up to parent */
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c = (struct node *) p;
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p = node_parent_rcu(c);
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}
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return NULL; /* Ready. Root of trie */
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} while ( (p = node_parent_rcu(c)) != NULL);
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return NULL; /* Root of trie */
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}
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static struct leaf *trie_firstleaf(struct trie *t)
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{
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struct tnode *n = (struct tnode *) rcu_dereference(t->trie);
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if (!n)
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return NULL;
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if (IS_LEAF(n)) /* trie is just a leaf */
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return (struct leaf *) n;
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return leaf_walk_rcu(n, NULL);
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}
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static struct leaf *trie_nextleaf(struct leaf *l)
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{
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struct node *c = (struct node *) l;
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struct tnode *p = node_parent(c);
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if (!p)
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return NULL; /* trie with just one leaf */
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return leaf_walk_rcu(p, c);
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}
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/*
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@ -1778,9 +1779,9 @@ static int fn_trie_flush(struct fib_table *tb)
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{
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struct trie *t = (struct trie *) tb->tb_data;
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struct leaf *ll = NULL, *l = NULL;
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int found = 0, h;
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int found = 0;
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for (h = 0; (l = nextleaf(t, l)) != NULL; h++) {
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for (l = trie_firstleaf(t); l; l = trie_nextleaf(l)) {
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found += trie_flush_leaf(t, l);
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if (ll && hlist_empty(&ll->list))
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@ -1887,7 +1888,6 @@ static int fn_trie_dump_fa(t_key key, int plen, struct list_head *fah,
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i++;
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continue;
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}
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BUG_ON(!fa->fa_info);
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if (fib_dump_info(skb, NETLINK_CB(cb->skb).pid,
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cb->nlh->nlmsg_seq,
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@ -1916,8 +1916,9 @@ static int fn_trie_dump_plen(struct trie *t, int plen, struct fib_table *tb,
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struct leaf *l = NULL;
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s_h = cb->args[3];
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h = 0;
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for (h = 0; (l = nextleaf(t, l)) != NULL; h++) {
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for (l = trie_firstleaf(t); l != NULL; h++, l = trie_nextleaf(l)) {
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if (h < s_h)
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continue;
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if (h > s_h)
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