fib_trie: Add tnode struct as a container for fields not needed in key_vector

This change pulls the fields not explicitly needed in the key_vector and
placed them in the new tnode structure.  By doing this we will eventually
be able to reduce the key_vector down to 16 bytes on 64 bit systems, and
12 bytes on 32 bit systems.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index b88c0d0f48edfdc6d777b50ff72ac9ac459211fd..3a062370fc32c68c33df750f02ca975d8c110de4 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -111,7 +111,11 @@ struct key_vector {
        };
 };
 
-#define TNODE_SIZE(n)  offsetof(struct key_vector, tnode[n])
+struct tnode {
+       struct key_vector kv[1];
+};
+
+#define TNODE_SIZE(n)  offsetof(struct tnode, kv[0].tnode[n])
 #define LEAF_SIZE      TNODE_SIZE(1)
 
 #ifdef CONFIG_IP_FIB_TRIE_STATS
@@ -288,7 +292,7 @@ static void __node_free_rcu(struct rcu_head *head)
 
 #define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
 
-static struct key_vector *tnode_alloc(int bits)
+static struct tnode *tnode_alloc(int bits)
 {
        size_t size;
 
@@ -317,48 +321,50 @@ static inline void empty_child_dec(struct key_vector *n)
 
 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
 {
-       struct key_vector *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
-       if (l) {
-               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->slen = fa->fa_slen;
-               l->pos = 0;
-               /* set bits to 0 indicating we are not a tnode */
-               l->bits = 0;
-
-               /* link leaf to fib alias */
-               INIT_HLIST_HEAD(&l->leaf);
-               hlist_add_head(&fa->fa_list, &l->leaf);
-       }
+       struct tnode *kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
+       struct key_vector *l = kv->kv;
+
+       if (!kv)
+               return NULL;
+
+       /* initialize key vector */
+       l->key = key;
+       l->pos = 0;
+       l->bits = 0;
+       l->slen = fa->fa_slen;
+
+       /* link leaf to fib alias */
+       INIT_HLIST_HEAD(&l->leaf);
+       hlist_add_head(&fa->fa_list, &l->leaf);
+
        return l;
 }
 
 static struct key_vector *tnode_new(t_key key, int pos, int bits)
 {
-       struct key_vector *tn = tnode_alloc(bits);
+       struct tnode *tnode = tnode_alloc(bits);
        unsigned int shift = pos + bits;
+       struct key_vector *tn = tnode->kv;
 
        /* verify bits and pos their msb bits clear and values are valid */
        BUG_ON(!bits || (shift > KEYLENGTH));
 
-       if (tn) {
-               tn->parent = NULL;
-               tn->slen = pos;
-               tn->pos = pos;
-               tn->bits = bits;
-               tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
-               if (bits == KEYLENGTH)
-                       tn->full_children = 1;
-               else
-                       tn->empty_children = 1ul << bits;
-       }
-
-       pr_debug("AT %p s=%zu %zu\n", tn, TNODE_SIZE(0),
+       pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
                 sizeof(struct key_vector *) << bits);
+
+       if (!tnode)
+               return NULL;
+
+       if (bits == KEYLENGTH)
+               tn->full_children = 1;
+       else
+               tn->empty_children = 1ul << bits;
+
+       tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
+       tn->pos = pos;
+       tn->bits = bits;
+       tn->slen = pos;
+
        return tn;
 }