fib_trie: Return pointer to tnode pointer in resize/inflate/halve
Resize related functions now all return a pointer to the pointer that references the object that was resized. 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
72be72607a
commit
8d8e810ca8
1 changed files with 65 additions and 41 deletions
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@ -144,7 +144,7 @@ struct trie {
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#endif
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};
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static void resize(struct trie *t, struct tnode *tn);
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static struct tnode **resize(struct trie *t, struct tnode *tn);
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static size_t tnode_free_size;
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/*
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@ -468,9 +468,11 @@ static void tnode_free(struct tnode *tn)
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}
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}
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static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
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static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,
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struct tnode *tn)
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{
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struct tnode *tp = node_parent(oldtnode);
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struct tnode **cptr;
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unsigned long i;
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/* setup the parent pointer out of and back into this node */
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@ -483,6 +485,9 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
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/* all pointers should be clean so we are done */
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tnode_free(oldtnode);
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/* record the pointer that is pointing to this node */
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cptr = tp ? tp->tnode : &t->trie;
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/* resize children now that oldtnode is freed */
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for (i = tnode_child_length(tn); i;) {
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struct tnode *inode = tnode_get_child(tn, --i);
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@ -491,9 +496,11 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
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if (tnode_full(tn, inode))
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resize(t, inode);
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}
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return cptr;
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}
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static int inflate(struct trie *t, struct tnode *oldtnode)
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static struct tnode __rcu **inflate(struct trie *t, struct tnode *oldtnode)
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{
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struct tnode *tn;
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unsigned long i;
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@ -503,7 +510,7 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
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tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
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if (!tn)
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return -ENOMEM;
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goto notnode;
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/* prepare oldtnode to be freed */
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tnode_free_init(oldtnode);
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@ -580,16 +587,15 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
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}
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/* setup the parent pointers into and out of this node */
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replace(t, oldtnode, tn);
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return 0;
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return replace(t, oldtnode, tn);
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nomem:
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/* all pointers should be clean so we are done */
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tnode_free(tn);
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return -ENOMEM;
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notnode:
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return NULL;
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}
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static int halve(struct trie *t, struct tnode *oldtnode)
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static struct tnode __rcu **halve(struct trie *t, struct tnode *oldtnode)
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{
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struct tnode *tn;
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unsigned long i;
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@ -598,7 +604,7 @@ static int halve(struct trie *t, struct tnode *oldtnode)
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tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
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if (!tn)
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return -ENOMEM;
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goto notnode;
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/* prepare oldtnode to be freed */
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tnode_free_init(oldtnode);
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@ -621,10 +627,8 @@ static int halve(struct trie *t, struct tnode *oldtnode)
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/* Two nonempty children */
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inode = tnode_new(node0->key, oldtnode->pos, 1);
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if (!inode) {
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tnode_free(tn);
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return -ENOMEM;
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}
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if (!inode)
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goto nomem;
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tnode_free_append(tn, inode);
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/* initialize pointers out of node */
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@ -637,9 +641,12 @@ static int halve(struct trie *t, struct tnode *oldtnode)
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}
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/* setup the parent pointers into and out of this node */
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replace(t, oldtnode, tn);
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return 0;
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return replace(t, oldtnode, tn);
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nomem:
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/* all pointers should be clean so we are done */
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tnode_free(tn);
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notnode:
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return NULL;
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}
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static void collapse(struct trie *t, struct tnode *oldtnode)
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@ -796,10 +803,14 @@ static bool should_collapse(const struct tnode *tn)
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}
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#define MAX_WORK 10
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static void resize(struct trie *t, struct tnode *tn)
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static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
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{
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#ifdef CONFIG_IP_FIB_TRIE_STATS
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struct trie_use_stats __percpu *stats = t->stats;
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#endif
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struct tnode *tp = node_parent(tn);
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struct tnode __rcu **cptr;
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unsigned long cindex = tp ? get_index(tn->key, tp) : 0;
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struct tnode __rcu **cptr = tp ? tp->tnode : &t->trie;
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int max_work = MAX_WORK;
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pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
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@ -809,52 +820,57 @@ static void resize(struct trie *t, struct tnode *tn)
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* doing it ourselves. This way we can let RCU fully do its
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* thing without us interfering
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*/
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cptr = tp ? &tp->tnode[get_index(tn->key, tp)] : &t->trie;
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BUG_ON(tn != rtnl_dereference(*cptr));
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BUG_ON(tn != rtnl_dereference(cptr[cindex]));
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/* Double as long as the resulting node has a number of
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* nonempty nodes that are above the threshold.
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*/
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while (should_inflate(tp, tn) && max_work) {
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if (inflate(t, tn)) {
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struct tnode __rcu **tcptr = inflate(t, tn);
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if (!tcptr) {
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#ifdef CONFIG_IP_FIB_TRIE_STATS
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this_cpu_inc(t->stats->resize_node_skipped);
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this_cpu_inc(stats->resize_node_skipped);
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#endif
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break;
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}
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max_work--;
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tn = rtnl_dereference(*cptr);
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cptr = tcptr;
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tn = rtnl_dereference(cptr[cindex]);
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}
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/* Return if at least one inflate is run */
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if (max_work != MAX_WORK)
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return;
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return cptr;
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/* Halve as long as the number of empty children in this
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* node is above threshold.
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*/
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while (should_halve(tp, tn) && max_work) {
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if (halve(t, tn)) {
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struct tnode __rcu **tcptr = halve(t, tn);
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if (!tcptr) {
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#ifdef CONFIG_IP_FIB_TRIE_STATS
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this_cpu_inc(t->stats->resize_node_skipped);
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this_cpu_inc(stats->resize_node_skipped);
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#endif
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break;
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}
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max_work--;
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tn = rtnl_dereference(*cptr);
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cptr = tcptr;
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tn = rtnl_dereference(cptr[cindex]);
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}
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/* Only one child remains */
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if (should_collapse(tn)) {
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collapse(t, tn);
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return;
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return cptr;
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}
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/* Return if at least one deflate was run */
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if (max_work != MAX_WORK)
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return;
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return cptr;
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/* push the suffix length to the parent node */
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if (tn->slen > tn->pos) {
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@ -863,6 +879,8 @@ static void resize(struct trie *t, struct tnode *tn)
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if (tp && (slen > tp->slen))
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tp->slen = slen;
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}
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return cptr;
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}
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static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
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@ -952,16 +970,18 @@ static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
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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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struct tnode __rcu **cptr = &t->trie;
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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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struct tnode *tp = node_parent(tn);
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cptr = resize(t, tn);
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if (!tp)
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break;
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tn = container_of(cptr, struct tnode, tnode[0]);
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}
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}
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/* only used from updater-side */
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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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@ -969,7 +989,7 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
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l = leaf_new(key, new);
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if (!l)
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return -ENOMEM;
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goto noleaf;
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/* retrieve child from parent node */
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if (tp)
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@ -987,10 +1007,8 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
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struct tnode *tn;
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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 -ENOMEM;
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}
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if (!tn)
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goto notnode;
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/* initialize routes out of node */
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NODE_INIT_PARENT(tn, tp);
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@ -1010,6 +1028,10 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
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trie_rebalance(t, tp);
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return 0;
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notnode:
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node_free(l);
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noleaf:
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return -ENOMEM;
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}
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static int fib_insert_alias(struct trie *t, struct tnode *tp,
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@ -1642,18 +1664,20 @@ int fib_table_flush(struct fib_table *tb)
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/* walk trie in reverse order */
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do {
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while (!(cindex--)) {
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struct tnode __rcu **cptr;
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t_key pkey = pn->key;
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n = pn;
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pn = node_parent(n);
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/* resize completed node */
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resize(t, n);
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cptr = resize(t, n);
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/* if we got the root we are done */
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if (!pn)
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goto flush_complete;
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pn = container_of(cptr, struct tnode, tnode[0]);
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cindex = get_index(pkey, pn);
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}
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