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-rw-r--r--net/ipv4/fib_trie.c192
1 files changed, 82 insertions, 110 deletions
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index d3dbb4821ae8..2b7220728b24 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -87,24 +87,38 @@
typedef unsigned int t_key;
-#define T_TNODE 0
-#define T_LEAF 1
-#define NODE_TYPE_MASK 0x1UL
-#define NODE_TYPE(node) ((node)->parent & NODE_TYPE_MASK)
+#define IS_TNODE(n) ((n)->bits)
+#define IS_LEAF(n) (!(n)->bits)
-#define IS_TNODE(n) (!(n->parent & T_LEAF))
-#define IS_LEAF(n) (n->parent & T_LEAF)
+struct tnode {
+ t_key key;
+ unsigned char bits; /* 2log(KEYLENGTH) bits needed */
+ unsigned char pos; /* 2log(KEYLENGTH) bits needed */
+ struct tnode __rcu *parent;
+ union {
+ struct rcu_head rcu;
+ struct tnode *tnode_free;
+ };
+ unsigned int full_children; /* KEYLENGTH bits needed */
+ unsigned int empty_children; /* KEYLENGTH bits needed */
+ struct rt_trie_node __rcu *child[0];
+};
struct rt_trie_node {
- unsigned long parent;
t_key key;
+ unsigned char bits;
+ unsigned char pos;
+ struct tnode __rcu *parent;
+ struct rcu_head rcu;
};
struct leaf {
- unsigned long parent;
t_key key;
- struct hlist_head list;
+ unsigned char bits;
+ unsigned char pos;
+ struct tnode __rcu *parent;
struct rcu_head rcu;
+ struct hlist_head list;
};
struct leaf_info {
@@ -115,20 +129,6 @@ struct leaf_info {
struct rcu_head rcu;
};
-struct tnode {
- unsigned long parent;
- t_key key;
- unsigned char pos; /* 2log(KEYLENGTH) bits needed */
- unsigned char bits; /* 2log(KEYLENGTH) bits needed */
- unsigned int full_children; /* KEYLENGTH bits needed */
- unsigned int empty_children; /* KEYLENGTH bits needed */
- union {
- struct rcu_head rcu;
- struct tnode *tnode_free;
- };
- struct rt_trie_node __rcu *child[0];
-};
-
#ifdef CONFIG_IP_FIB_TRIE_STATS
struct trie_use_stats {
unsigned int gets;
@@ -176,38 +176,27 @@ static const int sync_pages = 128;
static struct kmem_cache *fn_alias_kmem __read_mostly;
static struct kmem_cache *trie_leaf_kmem __read_mostly;
-/*
- * caller must hold RTNL
- */
-static inline struct tnode *node_parent(const struct rt_trie_node *node)
-{
- unsigned long parent;
+/* caller must hold RTNL */
+#define node_parent(n) rtnl_dereference((n)->parent)
- parent = rcu_dereference_index_check(node->parent, lockdep_rtnl_is_held());
+/* caller must hold RCU read lock or RTNL */
+#define node_parent_rcu(n) rcu_dereference_rtnl((n)->parent)
- return (struct tnode *)(parent & ~NODE_TYPE_MASK);
-}
-
-/*
- * caller must hold RCU read lock or RTNL
- */
-static inline struct tnode *node_parent_rcu(const struct rt_trie_node *node)
+/* wrapper for rcu_assign_pointer */
+static inline void node_set_parent(struct rt_trie_node *node, struct tnode *ptr)
{
- unsigned long parent;
-
- parent = rcu_dereference_index_check(node->parent, rcu_read_lock_held() ||
- lockdep_rtnl_is_held());
-
- return (struct tnode *)(parent & ~NODE_TYPE_MASK);
+ if (node)
+ rcu_assign_pointer(node->parent, ptr);
}
-/* Same as rcu_assign_pointer
- * but that macro() assumes that value is a pointer.
+#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER((n)->parent, p)
+
+/* 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 void node_set_parent(struct rt_trie_node *node, struct tnode *ptr)
+static inline int tnode_child_length(const struct tnode *tn)
{
- smp_wmb();
- node->parent = (unsigned long)ptr | NODE_TYPE(node);
+ return (1ul << tn->bits) & ~(1ul);
}
/*
@@ -215,7 +204,7 @@ static inline void node_set_parent(struct rt_trie_node *node, struct tnode *ptr)
*/
static inline struct rt_trie_node *tnode_get_child(const struct tnode *tn, unsigned int i)
{
- BUG_ON(i >= 1U << tn->bits);
+ BUG_ON(i >= tnode_child_length(tn));
return rtnl_dereference(tn->child[i]);
}
@@ -225,16 +214,11 @@ static inline struct rt_trie_node *tnode_get_child(const struct tnode *tn, unsig
*/
static inline struct rt_trie_node *tnode_get_child_rcu(const struct tnode *tn, unsigned int i)
{
- BUG_ON(i >= 1U << tn->bits);
+ BUG_ON(i >= tnode_child_length(tn));
return rcu_dereference_rtnl(tn->child[i]);
}
-static inline int tnode_child_length(const struct tnode *tn)
-{
- return 1 << tn->bits;
-}
-
static inline t_key mask_pfx(t_key k, unsigned int l)
{
return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l);
@@ -336,11 +320,6 @@ static inline int tkey_mismatch(t_key a, int offset, t_key b)
*/
-static inline void check_tnode(const struct tnode *tn)
-{
- WARN_ON(tn && tn->pos+tn->bits > 32);
-}
-
static const int halve_threshold = 25;
static const int inflate_threshold = 50;
static const int halve_threshold_root = 15;
@@ -426,11 +405,20 @@ static void tnode_free_flush(void)
}
}
-static struct leaf *leaf_new(void)
+static struct leaf *leaf_new(t_key key)
{
struct leaf *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
if (l) {
- l->parent = T_LEAF;
+ l->parent = NULL;
+ /* set key and pos to reflect full key value
+ * any trailing zeros in the key should be ignored
+ * as the nodes are searched
+ */
+ l->key = key;
+ l->pos = KEYLENGTH;
+ /* set bits to 0 indicating we are not a tnode */
+ l->bits = 0;
+
INIT_HLIST_HEAD(&l->list);
}
return l;
@@ -451,12 +439,16 @@ static struct tnode *tnode_new(t_key key, int pos, int bits)
{
size_t sz = sizeof(struct tnode) + (sizeof(struct rt_trie_node *) << bits);
struct tnode *tn = tnode_alloc(sz);
+ unsigned int shift = pos + bits;
+
+ /* verify bits and pos their msb bits clear and values are valid */
+ BUG_ON(!bits || (shift > KEYLENGTH));
if (tn) {
- tn->parent = T_TNODE;
+ tn->parent = NULL;
tn->pos = pos;
tn->bits = bits;
- tn->key = key;
+ tn->key = mask_pfx(key, pos);
tn->full_children = 0;
tn->empty_children = 1<<bits;
}
@@ -473,10 +465,7 @@ static struct tnode *tnode_new(t_key key, int pos, int bits)
static inline int tnode_full(const struct tnode *tn, const struct rt_trie_node *n)
{
- if (n == NULL || IS_LEAF(n))
- return 0;
-
- return ((struct tnode *) n)->pos == tn->pos + tn->bits;
+ return n && IS_TNODE(n) && (n->pos == (tn->pos + tn->bits));
}
static inline void put_child(struct tnode *tn, int i,
@@ -514,8 +503,7 @@ static void tnode_put_child_reorg(struct tnode *tn, int i, struct rt_trie_node *
else if (!wasfull && isfull)
tn->full_children++;
- if (n)
- node_set_parent(n, tn);
+ node_set_parent(n, tn);
rcu_assign_pointer(tn->child[i], n);
}
@@ -523,7 +511,7 @@ static void tnode_put_child_reorg(struct tnode *tn, int i, struct rt_trie_node *
#define MAX_WORK 10
static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
{
- int i;
+ struct rt_trie_node *n = NULL;
struct tnode *old_tn;
int inflate_threshold_use;
int halve_threshold_use;
@@ -536,12 +524,11 @@ static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
tn, inflate_threshold, halve_threshold);
/* No children */
- if (tn->empty_children == tnode_child_length(tn)) {
- tnode_free_safe(tn);
- return NULL;
- }
+ if (tn->empty_children > (tnode_child_length(tn) - 1))
+ goto no_children;
+
/* One child */
- if (tn->empty_children == tnode_child_length(tn) - 1)
+ if (tn->empty_children == (tnode_child_length(tn) - 1))
goto one_child;
/*
* Double as long as the resulting node has a number of
@@ -607,11 +594,9 @@ static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
*
*/
- check_tnode(tn);
-
/* Keep root node larger */
- if (!node_parent((struct rt_trie_node *)tn)) {
+ if (!node_parent(tn)) {
inflate_threshold_use = inflate_threshold_root;
halve_threshold_use = halve_threshold_root;
} else {
@@ -637,8 +622,6 @@ static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
}
}
- check_tnode(tn);
-
/* Return if at least one inflate is run */
if (max_work != MAX_WORK)
return (struct rt_trie_node *) tn;
@@ -666,21 +649,16 @@ static struct rt_trie_node *resize(struct trie *t, struct tnode *tn)
/* Only one child remains */
- if (tn->empty_children == tnode_child_length(tn) - 1) {
+ if (tn->empty_children == (tnode_child_length(tn) - 1)) {
+ unsigned long i;
one_child:
- for (i = 0; i < tnode_child_length(tn); i++) {
- struct rt_trie_node *n;
-
- n = rtnl_dereference(tn->child[i]);
- if (!n)
- continue;
-
- /* compress one level */
-
- node_set_parent(n, NULL);
- tnode_free_safe(tn);
- return n;
- }
+ for (i = tnode_child_length(tn); !n && i;)
+ n = tnode_get_child(tn, --i);
+no_children:
+ /* compress one level */
+ node_set_parent(n, NULL);
+ tnode_free_safe(tn);
+ return n;
}
return (struct rt_trie_node *) tn;
}
@@ -760,8 +738,7 @@ static struct tnode *inflate(struct trie *t, struct tnode *tn)
/* A leaf or an internal node with skipped bits */
- if (IS_LEAF(node) || ((struct tnode *) node)->pos >
- tn->pos + tn->bits - 1) {
+ if (IS_LEAF(node) || (node->pos > (tn->pos + tn->bits - 1))) {
put_child(tn,
tkey_extract_bits(node->key, oldtnode->pos, oldtnode->bits + 1),
node);
@@ -958,11 +935,9 @@ fib_find_node(struct trie *t, u32 key)
pos = 0;
n = rcu_dereference_rtnl(t->trie);
- while (n != NULL && NODE_TYPE(n) == T_TNODE) {
+ while (n && IS_TNODE(n)) {
tn = (struct tnode *) n;
- check_tnode(tn);
-
if (tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
pos = tn->pos + tn->bits;
n = tnode_get_child_rcu(tn,
@@ -988,7 +963,7 @@ static void trie_rebalance(struct trie *t, struct tnode *tn)
key = tn->key;
- while (tn != NULL && (tp = node_parent((struct rt_trie_node *)tn)) != NULL) {
+ while (tn != NULL && (tp = node_parent(tn)) != NULL) {
cindex = tkey_extract_bits(key, tp->pos, tp->bits);
wasfull = tnode_full(tp, tnode_get_child(tp, cindex));
tn = (struct tnode *)resize(t, tn);
@@ -996,7 +971,7 @@ static void trie_rebalance(struct trie *t, struct tnode *tn)
tnode_put_child_reorg(tp, cindex,
(struct rt_trie_node *)tn, wasfull);
- tp = node_parent((struct rt_trie_node *) tn);
+ tp = node_parent(tn);
if (!tp)
rcu_assign_pointer(t->trie, (struct rt_trie_node *)tn);
@@ -1048,11 +1023,9 @@ static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen)
* If it doesn't, we need to replace it with a T_TNODE.
*/
- while (n != NULL && NODE_TYPE(n) == T_TNODE) {
+ while (n && IS_TNODE(n)) {
tn = (struct tnode *) n;
- check_tnode(tn);
-
if (tkey_sub_equals(tn->key, pos, tn->pos-pos, key)) {
tp = tn;
pos = tn->pos + tn->bits;
@@ -1087,12 +1060,11 @@ static struct list_head *fib_insert_node(struct trie *t, u32 key, int plen)
insert_leaf_info(&l->list, li);
goto done;
}
- l = leaf_new();
+ l = leaf_new(key);
if (!l)
return NULL;
- l->key = key;
li = leaf_info_new(plen);
if (!li) {
@@ -1569,7 +1541,7 @@ backtrace:
if (chopped_off <= pn->bits) {
cindex &= ~(1 << (chopped_off-1));
} else {
- struct tnode *parent = node_parent_rcu((struct rt_trie_node *) pn);
+ struct tnode *parent = node_parent_rcu(pn);
if (!parent)
goto failed;
@@ -1597,7 +1569,7 @@ EXPORT_SYMBOL_GPL(fib_table_lookup);
*/
static void trie_leaf_remove(struct trie *t, struct leaf *l)
{
- struct tnode *tp = node_parent((struct rt_trie_node *) l);
+ struct tnode *tp = node_parent(l);
pr_debug("entering trie_leaf_remove(%p)\n", l);
@@ -2374,7 +2346,7 @@ static int fib_trie_seq_show(struct seq_file *seq, void *v)
if (IS_TNODE(n)) {
struct tnode *tn = (struct tnode *) n;
- __be32 prf = htonl(mask_pfx(tn->key, tn->pos));
+ __be32 prf = htonl(tn->key);
seq_indent(seq, iter->depth-1);
seq_printf(seq, " +-- %pI4/%d %d %d %d\n",
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-14 04:01:04 +0000