[RFC PATCH 14/29] fib_trie: Rename tnode_child_length to child_length

Alexander Duyck
2015-02-24T20:49:30Z

We are now checking the length of a key_vector instead of a tnode so it
makes sense to probably just rename this to child_length since it would
probably even be applicable to a leaf.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
net/ipv4/fib_trie.c | 53 ++++++++++++++++++++++++++++-----------------------
1 file changed, 29 insertions(+), 24 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index d9b192b..711f8f2 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -91,8 +91,6 @@ typedef unsigned int t_key;
#define IS_TNODE(n) ((n)->bits)
#define IS_LEAF(n) (!(n)->bits)

-#define get_index(_key, _kv) (((_key) ^ (_kv)->key) >> (_kv)->pos)
-
struct key_vector {
struct rcu_head rcu;
t_key empty_children; /* KEYLENGTH bits needed */
@@ -172,11 +170,18 @@ static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
/* This provides us with the number of children in this node, in the case of a
* leaf this will return 0 meaning none of the children are accessible.
*/
-static inline unsigned long tnode_child_length(const struct key_vector *tn)
+static inline unsigned long child_length(const struct key_vector *tn)
{
return (1ul << tn->bits) & ~(1ul);
}

+static inline unsigned long get_index(t_key key, struct key_vector *kv)
+{
+ unsigned long index = key ^ kv->key;
+
+ return index >> kv->pos;
+}
+
static inline struct fib_table *trie_get_table(struct trie *t)
{
unsigned long *tb_data = (unsigned long *)t;
@@ -360,7 +365,7 @@ static void put_child(struct key_vector *tn, unsigned long i,
struct key_vector *chi = get_child(tn, i);
int isfull, wasfull;

- BUG_ON(i >= tnode_child_length(tn));
+ BUG_ON(i >= child_length(tn));

/* update emptyChildren, overflow into fullChildren */
if (n == NULL && chi != NULL)
@@ -388,7 +393,7 @@ static void update_children(struct key_vector *tn)
unsigned long i;

/* update all of the child parent pointers */
- for (i = tnode_child_length(tn); i;) {
+ for (i = child_length(tn); i;) {
struct key_vector *inode = get_child(tn, --i);

if (!inode)
@@ -467,7 +472,7 @@ static struct key_vector __rcu **replace(struct trie *t,
cptr = tp ? tp->tnode : t->tnode;

/* resize children now that oldtnode is freed */
- for (i = tnode_child_length(tn); i;) {
+ for (i = child_length(tn); i;) {
struct key_vector *inode = get_child(tn, --i);

/* resize child node */
@@ -499,7 +504,7 @@ static struct key_vector __rcu **inflate(struct trie *t,
* point to existing tnodes and the links between our allocated
* nodes.
*/
- for (i = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
+ for (i = child_length(oldtnode), m = 1u << tn->pos; i;) {
struct key_vector *inode = get_child(oldtnode, --i);
struct key_vector *node0, *node1;
unsigned long j, k;
@@ -549,7 +554,7 @@ static struct key_vector __rcu **inflate(struct trie *t,
tnode_free_append(tn, node0);

/* populate child pointers in new nodes */
- for (k = tnode_child_length(inode), j = k / 2; j;) {
+ for (k = child_length(inode), j = k / 2; j;) {
put_child(node1, --j, get_child(inode, --k));
put_child(node0, j, get_child(inode, j));
put_child(node1, --j, get_child(inode, --k));
@@ -594,7 +599,7 @@ static struct key_vector __rcu **halve(struct trie *t,
* point to existing tnodes and the links between our allocated
* nodes.
*/
- for (i = tnode_child_length(oldtnode); i;) {
+ for (i = child_length(oldtnode); i;) {
struct key_vector *node1 = get_child(oldtnode, --i);
struct key_vector *node0 = get_child(oldtnode, --i);
struct key_vector *inode;
@@ -635,7 +640,7 @@ static void collapse(struct trie *t, struct key_vector *oldtnode)
unsigned long i;

/* scan the tnode looking for that one child that might still exist */
- for (n = NULL, i = tnode_child_length(oldtnode); !n && i;)
+ for (n = NULL, i = child_length(oldtnode); !n && i;)
n = get_child(oldtnode, --i);

/* compress one level */
@@ -657,7 +662,7 @@ static unsigned char update_suffix(struct key_vector *tn)
* why we start with a stride of 2 since a stride of 1 would
* represent the nodes with suffix length equal to tn->pos
*/
- for (i = 0, stride = 0x2ul ; i < tnode_child_length(tn); i += stride) {
+ for (i = 0, stride = 0x2ul ; i < child_length(tn); i += stride) {
struct key_vector *n = get_child(tn, i);

if (!n || (n->slen <= slen))
@@ -690,12 +695,12 @@ static unsigned char update_suffix(struct key_vector *tn)
*
* 'high' in this instance is the variable 'inflate_threshold'. It
* is expressed as a percentage, so we multiply it with
- * tnode_child_length() and instead of multiplying by 2 (since the
+ * child_length() and instead of multiplying by 2 (since the
* child array will be doubled by inflate()) and multiplying
* the left-hand side by 100 (to handle the percentage thing) we
* multiply the left-hand side by 50.
*
- * The left-hand side may look a bit weird: tnode_child_length(tn)
+ * The left-hand side may look a bit weird: child_length(tn)
* - tn->empty_children is of course the number of non-null children
* in the current node. tn->full_children is the number of "full"
* children, that is non-null tnodes with a skip value of 0.
@@ -705,10 +710,10 @@ static unsigned char update_suffix(struct key_vector *tn)
* A clearer way to write this would be:
*
* to_be_doubled = tn->full_children;
- * not_to_be_doubled = tnode_child_length(tn) - tn->empty_children -
+ * not_to_be_doubled = child_length(tn) - tn->empty_children -
* tn->full_children;
*
- * new_child_length = tnode_child_length(tn) * 2;
+ * new_child_length = child_length(tn) * 2;
*
* new_fill_factor = 100 * (not_to_be_doubled + 2*to_be_doubled) /
* new_child_length;
@@ -725,23 +730,23 @@ static unsigned char update_suffix(struct key_vector *tn)
* inflate_threshold * new_child_length
*
* expand not_to_be_doubled and to_be_doubled, and shorten:
- * 100 * (tnode_child_length(tn) - tn->empty_children +
+ * 100 * (child_length(tn) - tn->empty_children +
* tn->full_children) >= inflate_threshold * new_child_length
*
* expand new_child_length:
- * 100 * (tnode_child_length(tn) - tn->empty_children +
+ * 100 * (child_length(tn) - tn->empty_children +
* tn->full_children) >=
- * inflate_threshold * tnode_child_length(tn) * 2
+ * inflate_threshold * child_length(tn) * 2
*
* shorten again:
- * 50 * (tn->full_children + tnode_child_length(tn) -
+ * 50 * (tn->full_children + child_length(tn) -
* tn->empty_children) >= inflate_threshold *
- * tnode_child_length(tn)
+ * child_length(tn)
*
*/
static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
{
- unsigned long used = tnode_child_length(tn);
+ unsigned long used = child_length(tn);
unsigned long threshold = used;

/* Keep root node larger */
@@ -756,7 +761,7 @@ static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)

static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
{
- unsigned long used = tnode_child_length(tn);
+ unsigned long used = child_length(tn);
unsigned long threshold = used;

/* Keep root node larger */
@@ -770,7 +775,7 @@ static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)

static inline bool should_collapse(struct key_vector *tn)
{
- unsigned long used = tnode_child_length(tn);
+ unsigned long used = child_length(tn);

used -= tn->empty_children;

@@ -1774,7 +1779,7 @@ static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
iter->tnode, iter->index, iter->depth);
rescan:
- while (cindex < tnode_child_length(tn)) {
+ while (cindex < child_length(tn)) {
struct key_vector *n = get_child_rcu(tn, cindex);

if (n) {