fib_trie: Update insert and delete to make use of tp from find_node
This change makes it so that the insert and delete functions make use of the tnode pointer returned in the fib_find_node call. By doing this we will not have to rely on the parent pointer in the leaf which will be going away soon. Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alexander Duyck
David S. Miller
parent
d4a975e83f
commit
d5d6487cb8
1 changed files with 97 additions and 144 deletions
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@ -300,7 +300,7 @@ static inline void empty_child_dec(struct tnode *n)
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n->empty_children-- ? : n->full_children--;
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}
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static struct tnode *leaf_new(t_key key)
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static struct tnode *leaf_new(t_key key, struct fib_alias *fa)
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{
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struct tnode *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
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if (l) {
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@ -310,12 +310,14 @@ static struct tnode *leaf_new(t_key key)
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* as the nodes are searched
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*/
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l->key = key;
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l->slen = 0;
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l->slen = fa->fa_slen;
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l->pos = 0;
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/* set bits to 0 indicating we are not a tnode */
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l->bits = 0;
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/* link leaf to fib alias */
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INIT_HLIST_HEAD(&l->leaf);
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hlist_add_head(&fa->fa_list, &l->leaf);
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}
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return l;
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}
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@ -842,10 +844,8 @@ static void resize(struct trie *t, struct tnode *tn)
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}
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}
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static void leaf_pull_suffix(struct tnode *l)
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static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
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{
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struct tnode *tp = node_parent(l);
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while (tp && (tp->slen > tp->pos) && (tp->slen > l->slen)) {
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if (update_suffix(tp) > l->slen)
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break;
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@ -853,10 +853,8 @@ static void leaf_pull_suffix(struct tnode *l)
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}
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}
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static void leaf_push_suffix(struct tnode *l)
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static void leaf_push_suffix(struct tnode *tn, struct tnode *l)
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{
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struct tnode *tn = node_parent(l);
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/* if this is a new leaf then tn will be NULL and we can sort
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* out parent suffix lengths as a part of trie_rebalance
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*/
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@ -866,51 +864,6 @@ static void leaf_push_suffix(struct tnode *l)
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}
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}
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static void fib_remove_alias(struct tnode *l, struct fib_alias *old)
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{
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/* record the location of the previous list_info entry */
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struct hlist_node **pprev = old->fa_list.pprev;
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struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
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/* remove the fib_alias from the list */
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hlist_del_rcu(&old->fa_list);
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/* only access fa if it is pointing at the last valid hlist_node */
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if (hlist_empty(&l->leaf) || (*pprev))
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return;
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/* update the trie with the latest suffix length */
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l->slen = fa->fa_slen;
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leaf_pull_suffix(l);
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}
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static void fib_insert_alias(struct tnode *l, struct fib_alias *fa,
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struct fib_alias *new)
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{
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if (fa) {
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hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
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} else {
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struct fib_alias *last;
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hlist_for_each_entry(last, &l->leaf, fa_list) {
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if (new->fa_slen < last->fa_slen)
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break;
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fa = last;
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}
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if (fa)
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hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
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else
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hlist_add_head_rcu(&new->fa_list, &l->leaf);
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}
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/* if we added to the tail node then we need to update slen */
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if (l->slen < new->fa_slen) {
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l->slen = new->fa_slen;
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leaf_push_suffix(l);
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}
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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 tnode *fib_find_node(struct trie *t, struct tnode **tn, u32 key)
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{
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@ -980,61 +933,28 @@ static void trie_rebalance(struct trie *t, struct tnode *tn)
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{
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struct tnode *tp;
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while ((tp = node_parent(tn)) != NULL) {
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while (tn) {
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tp = node_parent(tn);
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resize(t, tn);
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tn = tp;
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}
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/* Handle last (top) tnode */
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if (IS_TNODE(tn))
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resize(t, tn);
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}
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/* only used from updater-side */
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static struct tnode *fib_insert_node(struct trie *t, u32 key, int plen)
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static int fib_insert_node(struct trie *t, struct tnode *tp,
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struct fib_alias *new, t_key key)
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{
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struct tnode *l, *n, *tp = NULL;
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struct tnode *n, *l;
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n = rtnl_dereference(t->trie);
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/* If we point to NULL, stop. Either the tree is empty and we should
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* just put a new leaf in if, or we have reached an empty child slot,
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* and we should just put our new leaf in that.
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*
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* If we hit a node with a key that does't match then we should stop
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* and create a new tnode to replace that node and insert ourselves
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* and the other node into the new tnode.
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*/
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while (n) {
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unsigned long index = get_index(key, n);
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/* This bit of code is a bit tricky but it combines multiple
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* checks into a single check. The prefix consists of the
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* prefix plus zeros for the "bits" in the prefix. The index
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* is the difference between the key and this value. From
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* this we can actually derive several pieces of data.
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* if !(index >> bits)
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* we know the value is child index
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* else
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* we have a mismatch in skip bits and failed
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*/
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if (index >> n->bits)
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break;
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/* we have found a leaf. Prefixes have already been compared */
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if (IS_LEAF(n)) {
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/* Case 1: n is a leaf, and prefixes match*/
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return n;
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}
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tp = n;
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n = tnode_get_child_rcu(n, index);
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}
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l = leaf_new(key);
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l = leaf_new(key, new);
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if (!l)
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return NULL;
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return -ENOMEM;
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/* retrieve child from parent node */
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if (tp)
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n = tnode_get_child(tp, get_index(key, tp));
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else
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n = rcu_dereference_rtnl(t->trie);
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/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
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*
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@ -1048,7 +968,7 @@ static struct tnode *fib_insert_node(struct trie *t, u32 key, int plen)
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tn = tnode_new(key, __fls(key ^ n->key), 1);
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if (!tn) {
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node_free(l);
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return NULL;
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return -ENOMEM;
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}
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/* initialize routes out of node */
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@ -1064,20 +984,47 @@ static struct tnode *fib_insert_node(struct trie *t, u32 key, int plen)
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}
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/* Case 3: n is NULL, and will just insert a new leaf */
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if (tp) {
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NODE_INIT_PARENT(l, tp);
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put_child(tp, get_index(key, tp), l);
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trie_rebalance(t, tp);
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} else {
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rcu_assign_pointer(t->trie, l);
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}
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NODE_INIT_PARENT(l, tp);
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put_child_root(tp, t, key, l);
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trie_rebalance(t, tp);
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return l;
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return 0;
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}
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/*
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* Caller must hold RTNL.
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*/
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static int fib_insert_alias(struct trie *t, struct tnode *tp,
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struct tnode *l, struct fib_alias *new,
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struct fib_alias *fa, t_key key)
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{
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if (!l)
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return fib_insert_node(t, tp, new, key);
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if (fa) {
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hlist_add_before_rcu(&new->fa_list, &fa->fa_list);
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} else {
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struct fib_alias *last;
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hlist_for_each_entry(last, &l->leaf, fa_list) {
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if (new->fa_slen < last->fa_slen)
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break;
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fa = last;
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}
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if (fa)
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hlist_add_behind_rcu(&new->fa_list, &fa->fa_list);
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else
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hlist_add_head_rcu(&new->fa_list, &l->leaf);
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}
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/* if we added to the tail node then we need to update slen */
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if (l->slen < new->fa_slen) {
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l->slen = new->fa_slen;
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leaf_push_suffix(tp, l);
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}
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return 0;
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}
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/* Caller must hold RTNL. */
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int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
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{
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struct trie *t = (struct trie *)tb->tb_data;
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@ -1205,19 +1152,13 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
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new_fa->fa_slen = slen;
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/* Insert new entry to the list. */
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if (!l) {
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l = fib_insert_node(t, key, plen);
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if (unlikely(!l)) {
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err = -ENOMEM;
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goto out_free_new_fa;
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}
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}
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err = fib_insert_alias(t, tp, l, new_fa, fa, key);
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if (err)
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goto out_free_new_fa;
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if (!plen)
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tb->tb_num_default++;
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fib_insert_alias(l, fa, new_fa);
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rt_cache_flush(cfg->fc_nlinfo.nl_net);
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rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, tb->tb_id,
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&cfg->fc_nlinfo, 0);
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@ -1406,9 +1347,36 @@ found:
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}
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EXPORT_SYMBOL_GPL(fib_table_lookup);
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/*
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* Caller must hold RTNL.
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*/
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static void fib_remove_alias(struct trie *t, struct tnode *tp,
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struct tnode *l, struct fib_alias *old)
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{
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/* record the location of the previous list_info entry */
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struct hlist_node **pprev = old->fa_list.pprev;
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struct fib_alias *fa = hlist_entry(pprev, typeof(*fa), fa_list.next);
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/* remove the fib_alias from the list */
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hlist_del_rcu(&old->fa_list);
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/* if we emptied the list this leaf will be freed and we can sort
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* out parent suffix lengths as a part of trie_rebalance
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*/
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if (hlist_empty(&l->leaf)) {
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put_child_root(tp, t, l->key, NULL);
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node_free(l);
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trie_rebalance(t, tp);
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return;
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}
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/* only access fa if it is pointing at the last valid hlist_node */
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if (*pprev)
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return;
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/* update the trie with the latest suffix length */
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l->slen = fa->fa_slen;
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leaf_pull_suffix(tp, l);
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}
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/* Caller must hold RTNL. */
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int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
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{
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struct trie *t = (struct trie *) tb->tb_data;
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@ -1432,7 +1400,6 @@ int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
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return -ESRCH;
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fa = fib_find_alias(&l->leaf, slen, tos, 0);
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if (!fa)
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return -ESRCH;
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@ -1461,33 +1428,19 @@ int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
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if (!fa_to_delete)
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return -ESRCH;
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fa = fa_to_delete;
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rtmsg_fib(RTM_DELROUTE, htonl(key), fa, plen, tb->tb_id,
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rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
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&cfg->fc_nlinfo, 0);
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fib_remove_alias(l, fa);
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if (!plen)
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tb->tb_num_default--;
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if (hlist_empty(&l->leaf)) {
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struct tnode *tp = node_parent(l);
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fib_remove_alias(t, tp, l, fa_to_delete);
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if (tp) {
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put_child(tp, get_index(l->key, tp), NULL);
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trie_rebalance(t, tp);
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} else {
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RCU_INIT_POINTER(t->trie, NULL);
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}
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node_free(l);
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}
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if (fa->fa_state & FA_S_ACCESSED)
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if (fa_to_delete->fa_state & FA_S_ACCESSED)
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rt_cache_flush(cfg->fc_nlinfo.nl_net);
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fib_release_info(fa->fa_info);
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alias_free_mem_rcu(fa);
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fib_release_info(fa_to_delete->fa_info);
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alias_free_mem_rcu(fa_to_delete);
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return 0;
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}
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@ -1626,7 +1579,7 @@ backtrace:
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put_child_root(pn, t, n->key, NULL);
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node_free(n);
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} else {
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leaf_pull_suffix(n);
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leaf_pull_suffix(pn, n);
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}
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/* if trie is leaf only loop is completed */
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