[net-next PATCH 0/9] The rest of the FIB patches (add key_vector to fib_table)

[net-next PATCH 0/9] The rest of the FIB patches (add key_vector to fib_table)

[Alexander Duyck]

This patch series is the rest of what I had planned for this kernel
release.  It adds a structure called key_vector which is embedded within
every tnode, leaf, and the trie root itself.  By doing this we can navigate
from any point within the trie to any other point fairly quickly and
avoiding NULL pointer checks in the case of a backtrace.  As a result we
can pipeline things a bit further since we don't have to worry about
dereferencing NULL in a backtrace.  This can amount to significant savings
on a long backtrace.

If needed these patches can be deferred/rebased depending on the needs of
the switchdev FIB offload work.

---

Alexander Duyck (9):
      fib_trie: Return pointer to tnode pointer in resize/inflate/halve
      fib_trie: Rename tnode to key_vector
      fib_trie: replace tnode_get_child functions with get_child macros
      fib_trie: Rename tnode_child_length to child_length
      fib_trie: Add tnode struct as a container for fields not needed in key_vector
      fib_trie: Move rcu from key_vector to tnode, add accessors.
      fib_trie: Pull empty_children and full_children into tnode
      fib_trie: Move parent from key_vector to tnode
      fib_trie: Add key vector to root, return parent key_vector in resize


 net/ipv4/fib_trie.c |  747 ++++++++++++++++++++++++++-------------------------
 1 file changed, 374 insertions(+), 373 deletions(-)

--

[net-next PATCH 1/9] fib_trie: Return pointer to tnode pointer in resize/inflate/halve

[Alexander Duyck]

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>
---
 net/ipv4/fib_trie.c |  106 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 65 insertions(+), 41 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index fae34ad..7e96529 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -143,7 +143,7 @@ struct trie {
 #endif
 };
 
-static void resize(struct trie *t, struct tnode *tn);
+static struct tnode **resize(struct trie *t, struct tnode *tn);
 static size_t tnode_free_size;
 
 /*
@@ -467,9 +467,11 @@ static void tnode_free(struct tnode *tn)
 	}
 }
 
-static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
+static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,
+				    struct tnode *tn)
 {
 	struct tnode *tp = node_parent(oldtnode);
+	struct tnode **cptr;
 	unsigned long i;
 
 	/* setup the parent pointer out of and back into this node */
@@ -482,6 +484,9 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
 	/* all pointers should be clean so we are done */
 	tnode_free(oldtnode);
 
+	/* record the pointer that is pointing to this node */
+	cptr = tp ? tp->tnode : &t->trie;
+
 	/* resize children now that oldtnode is freed */
 	for (i = tnode_child_length(tn); i;) {
 		struct tnode *inode = tnode_get_child(tn, --i);
@@ -490,9 +495,11 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
 		if (tnode_full(tn, inode))
 			resize(t, inode);
 	}
+
+	return cptr;
 }
 
-static int inflate(struct trie *t, struct tnode *oldtnode)
+static struct tnode __rcu **inflate(struct trie *t, struct tnode *oldtnode)
 {
 	struct tnode *tn;
 	unsigned long i;
@@ -502,7 +509,7 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
 
 	tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
 	if (!tn)
-		return -ENOMEM;
+		goto notnode;
 
 	/* prepare oldtnode to be freed */
 	tnode_free_init(oldtnode);
@@ -579,16 +586,15 @@ static int inflate(struct trie *t, struct tnode *oldtnode)
 	}
 
 	/* setup the parent pointers into and out of this node */
-	replace(t, oldtnode, tn);
-
-	return 0;
+	return replace(t, oldtnode, tn);
 nomem:
 	/* all pointers should be clean so we are done */
 	tnode_free(tn);
-	return -ENOMEM;
+notnode:
+	return NULL;
 }
 
-static int halve(struct trie *t, struct tnode *oldtnode)
+static struct tnode __rcu **halve(struct trie *t, struct tnode *oldtnode)
 {
 	struct tnode *tn;
 	unsigned long i;
@@ -597,7 +603,7 @@ static int halve(struct trie *t, struct tnode *oldtnode)
 
 	tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
 	if (!tn)
-		return -ENOMEM;
+		goto notnode;
 
 	/* prepare oldtnode to be freed */
 	tnode_free_init(oldtnode);
@@ -620,10 +626,8 @@ static int halve(struct trie *t, struct tnode *oldtnode)
 
 		/* Two nonempty children */
 		inode = tnode_new(node0->key, oldtnode->pos, 1);
-		if (!inode) {
-			tnode_free(tn);
-			return -ENOMEM;
-		}
+		if (!inode)
+			goto nomem;
 		tnode_free_append(tn, inode);
 
 		/* initialize pointers out of node */
@@ -636,9 +640,12 @@ static int halve(struct trie *t, struct tnode *oldtnode)
 	}
 
 	/* setup the parent pointers into and out of this node */
-	replace(t, oldtnode, tn);
-
-	return 0;
+	return replace(t, oldtnode, tn);
+nomem:
+	/* all pointers should be clean so we are done */
+	tnode_free(tn);
+notnode:
+	return NULL;
 }
 
 static void collapse(struct trie *t, struct tnode *oldtnode)
@@ -795,10 +802,14 @@ static bool should_collapse(const struct tnode *tn)
 }
 
 #define MAX_WORK 10
-static void resize(struct trie *t, struct tnode *tn)
+static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
 {
+#ifdef CONFIG_IP_FIB_TRIE_STATS
+	struct trie_use_stats __percpu *stats = t->stats;
+#endif
 	struct tnode *tp = node_parent(tn);
-	struct tnode __rcu **cptr;
+	unsigned long cindex = tp ? get_index(tn->key, tp) : 0;
+	struct tnode __rcu **cptr = tp ? tp->tnode : &t->trie;
 	int max_work = MAX_WORK;
 
 	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
@@ -808,52 +819,57 @@ static void resize(struct trie *t, struct tnode *tn)
 	 * doing it ourselves.  This way we can let RCU fully do its
 	 * thing without us interfering
 	 */
-	cptr = tp ? &tp->tnode[get_index(tn->key, tp)] : &t->trie;
-	BUG_ON(tn != rtnl_dereference(*cptr));
+	BUG_ON(tn != rtnl_dereference(cptr[cindex]));
 
 	/* Double as long as the resulting node has a number of
 	 * nonempty nodes that are above the threshold.
 	 */
 	while (should_inflate(tp, tn) && max_work) {
-		if (inflate(t, tn)) {
+		struct tnode __rcu **tcptr = inflate(t, tn);
+
+		if (!tcptr) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
-			this_cpu_inc(t->stats->resize_node_skipped);
+			this_cpu_inc(stats->resize_node_skipped);
 #endif
 			break;
 		}
 
 		max_work--;
-		tn = rtnl_dereference(*cptr);
+		cptr = tcptr;
+		tn = rtnl_dereference(cptr[cindex]);
 	}
 
 	/* Return if at least one inflate is run */
 	if (max_work != MAX_WORK)
-		return;
+		return cptr;
 
 	/* Halve as long as the number of empty children in this
 	 * node is above threshold.
 	 */
 	while (should_halve(tp, tn) && max_work) {
-		if (halve(t, tn)) {
+		struct tnode __rcu **tcptr = halve(t, tn);
+
+		if (!tcptr) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
-			this_cpu_inc(t->stats->resize_node_skipped);
+			this_cpu_inc(stats->resize_node_skipped);
 #endif
 			break;
 		}
 
 		max_work--;
-		tn = rtnl_dereference(*cptr);
+		cptr = tcptr;
+		tn = rtnl_dereference(cptr[cindex]);
 	}
 
 	/* Only one child remains */
 	if (should_collapse(tn)) {
 		collapse(t, tn);
-		return;
+		return cptr;
 	}
 
 	/* Return if at least one deflate was run */
 	if (max_work != MAX_WORK)
-		return;
+		return cptr;
 
 	/* push the suffix length to the parent node */
 	if (tn->slen > tn->pos) {
@@ -862,6 +878,8 @@ static void resize(struct trie *t, struct tnode *tn)
 		if (tp && (slen > tp->slen))
 			tp->slen = slen;
 	}
+
+	return cptr;
 }
 
 static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
@@ -951,16 +969,18 @@ static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
 
 static void trie_rebalance(struct trie *t, struct tnode *tn)
 {
-	struct tnode *tp;
+	struct tnode __rcu **cptr = &t->trie;
 
 	while (tn) {
-		tp = node_parent(tn);
-		resize(t, tn);
-		tn = tp;
+		struct tnode *tp = node_parent(tn);
+
+		cptr = resize(t, tn);
+		if (!tp)
+			break;
+		tn = container_of(cptr, struct tnode, tnode[0]);
 	}
 }
 
-/* only used from updater-side */
 static int fib_insert_node(struct trie *t, struct tnode *tp,
 			   struct fib_alias *new, t_key key)
 {
@@ -968,7 +988,7 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
 
 	l = leaf_new(key, new);
 	if (!l)
-		return -ENOMEM;
+		goto noleaf;
 
 	/* retrieve child from parent node */
 	if (tp)
@@ -986,10 +1006,8 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
 		struct tnode *tn;
 
 		tn = tnode_new(key, __fls(key ^ n->key), 1);
-		if (!tn) {
-			node_free(l);
-			return -ENOMEM;
-		}
+		if (!tn)
+			goto notnode;
 
 		/* initialize routes out of node */
 		NODE_INIT_PARENT(tn, tp);
@@ -1009,6 +1027,10 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
 	trie_rebalance(t, tp);
 
 	return 0;
+notnode:
+	node_free(l);
+noleaf:
+	return -ENOMEM;
 }
 
 static int fib_insert_alias(struct trie *t, struct tnode *tp,
@@ -1562,18 +1584,20 @@ backtrace:
 		/* walk trie in reverse order */
 		do {
 			while (!(cindex--)) {
+				struct tnode __rcu **cptr;
 				t_key pkey = pn->key;
 
 				n = pn;
 				pn = node_parent(n);
 
 				/* resize completed node */
-				resize(t, n);
+				cptr = resize(t, n);
 
 				/* if we got the root we are done */
 				if (!pn)
 					goto flush_complete;
 
+				pn = container_of(cptr, struct tnode, tnode[0]);
 				cindex = get_index(pkey, pn);
 			}
 

[net-next PATCH 2/9] fib_trie: Rename tnode to key_vector

[Alexander Duyck]

Rename the tnode to key_vector.  The key_vector will be the eventual
container for all of the information needed by either a leaf or a tnode.
The final result should be much smaller than the 40 bytes currently needed
for either one.

This also updates the trie struct so that it contains an array of size 1 of
tnode pointers.  This is to bring the structure more inline with how an
actual tnode itself is configured.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |  243 ++++++++++++++++++++++++++-------------------------
 1 file changed, 126 insertions(+), 117 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 7e96529..e8a99c6 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -93,12 +93,12 @@ typedef unsigned int t_key;
 
 #define get_index(_key, _kv) (((_key) ^ (_kv)->key) >> (_kv)->pos)
 
-struct tnode {
+struct key_vector {
 	struct rcu_head rcu;
 
 	t_key empty_children; /* KEYLENGTH bits needed */
 	t_key full_children;  /* KEYLENGTH bits needed */
-	struct tnode __rcu *parent;
+	struct key_vector __rcu *parent;
 
 	t_key key;
 	unsigned char pos;		/* 2log(KEYLENGTH) bits needed */
@@ -108,11 +108,11 @@ struct tnode {
 		/* This list pointer if valid if (pos | bits) == 0 (LEAF) */
 		struct hlist_head leaf;
 		/* This array is valid if (pos | bits) > 0 (TNODE) */
-		struct tnode __rcu *tnode[0];
+		struct key_vector __rcu *tnode[0];
 	};
 };
 
-#define TNODE_SIZE(n)	offsetof(struct tnode, tnode[n])
+#define TNODE_SIZE(n)	offsetof(struct key_vector, tnode[n])
 #define LEAF_SIZE	TNODE_SIZE(1)
 
 #ifdef CONFIG_IP_FIB_TRIE_STATS
@@ -137,13 +137,13 @@ struct trie_stat {
 };
 
 struct trie {
-	struct tnode __rcu *trie;
+	struct key_vector __rcu *tnode[1];
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	struct trie_use_stats __percpu *stats;
 #endif
 };
 
-static struct tnode **resize(struct trie *t, struct tnode *tn);
+static struct key_vector **resize(struct trie *t, struct key_vector *tn);
 static size_t tnode_free_size;
 
 /*
@@ -163,7 +163,7 @@ static struct kmem_cache *trie_leaf_kmem __read_mostly;
 #define node_parent_rcu(n) rcu_dereference_rtnl((n)->parent)
 
 /* wrapper for rcu_assign_pointer */
-static inline void node_set_parent(struct tnode *n, struct tnode *tp)
+static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
 {
 	if (n)
 		rcu_assign_pointer(n->parent, tp);
@@ -174,21 +174,21 @@ static inline void node_set_parent(struct tnode *n, struct tnode *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 tnode *tn)
+static inline unsigned long tnode_child_length(const struct key_vector *tn)
 {
 	return (1ul << tn->bits) & ~(1ul);
 }
 
 /* caller must hold RTNL */
-static inline struct tnode *tnode_get_child(const struct tnode *tn,
-					    unsigned long i)
+static inline struct key_vector *tnode_get_child(struct key_vector *tn,
+						 unsigned long i)
 {
 	return rtnl_dereference(tn->tnode[i]);
 }
 
 /* caller must hold RCU read lock or RTNL */
-static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn,
-						unsigned long i)
+static inline struct key_vector *tnode_get_child_rcu(struct key_vector *tn,
+						     unsigned long i)
 {
 	return rcu_dereference_rtnl(tn->tnode[i]);
 }
@@ -276,13 +276,13 @@ static inline void alias_free_mem_rcu(struct fib_alias *fa)
 }
 
 #define TNODE_KMALLOC_MAX \
-	ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct tnode *))
+	ilog2((PAGE_SIZE - TNODE_SIZE(0)) / sizeof(struct key_vector *))
 #define TNODE_VMALLOC_MAX \
-	ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct tnode *))
+	ilog2((SIZE_MAX - TNODE_SIZE(0)) / sizeof(struct key_vector *))
 
 static void __node_free_rcu(struct rcu_head *head)
 {
-	struct tnode *n = container_of(head, struct tnode, rcu);
+	struct key_vector *n = container_of(head, struct key_vector, rcu);
 
 	if (IS_LEAF(n))
 		kmem_cache_free(trie_leaf_kmem, n);
@@ -294,7 +294,7 @@ static void __node_free_rcu(struct rcu_head *head)
 
 #define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
 
-static struct tnode *tnode_alloc(int bits)
+static struct key_vector *tnode_alloc(int bits)
 {
 	size_t size;
 
@@ -311,19 +311,19 @@ static struct tnode *tnode_alloc(int bits)
 		return vzalloc(size);
 }
 
-static inline void empty_child_inc(struct tnode *n)
+static inline void empty_child_inc(struct key_vector *n)
 {
 	++n->empty_children ? : ++n->full_children;
 }
 
-static inline void empty_child_dec(struct tnode *n)
+static inline void empty_child_dec(struct key_vector *n)
 {
 	n->empty_children-- ? : n->full_children--;
 }
 
-static struct tnode *leaf_new(t_key key, struct fib_alias *fa)
+static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
 {
-	struct tnode *l = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
+	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
@@ -343,9 +343,9 @@ static struct tnode *leaf_new(t_key key, struct fib_alias *fa)
 	return l;
 }
 
-static struct tnode *tnode_new(t_key key, int pos, int bits)
+static struct key_vector *tnode_new(t_key key, int pos, int bits)
 {
-	struct tnode *tn = tnode_alloc(bits);
+	struct key_vector *tn = tnode_alloc(bits);
 	unsigned int shift = pos + bits;
 
 	/* verify bits and pos their msb bits clear and values are valid */
@@ -364,14 +364,14 @@ static struct tnode *tnode_new(t_key key, int pos, int bits)
 	}
 
 	pr_debug("AT %p s=%zu %zu\n", tn, TNODE_SIZE(0),
-		 sizeof(struct tnode *) << bits);
+		 sizeof(struct key_vector *) << bits);
 	return tn;
 }
 
 /* Check whether a tnode 'n' is "full", i.e. it is an internal node
  * and no bits are skipped. See discussion in dyntree paper p. 6
  */
-static inline int tnode_full(const struct tnode *tn, const struct tnode *n)
+static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
 {
 	return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
 }
@@ -379,9 +379,10 @@ static inline int tnode_full(const struct tnode *tn, const struct tnode *n)
 /* Add a child at position i overwriting the old value.
  * Update the value of full_children and empty_children.
  */
-static void put_child(struct tnode *tn, unsigned long i, struct tnode *n)
+static void put_child(struct key_vector *tn, unsigned long i,
+		      struct key_vector *n)
 {
-	struct tnode *chi = tnode_get_child(tn, i);
+	struct key_vector *chi = tnode_get_child(tn, i);
 	int isfull, wasfull;
 
 	BUG_ON(i >= tnode_child_length(tn));
@@ -407,13 +408,13 @@ static void put_child(struct tnode *tn, unsigned long i, struct tnode *n)
 	rcu_assign_pointer(tn->tnode[i], n);
 }
 
-static void update_children(struct tnode *tn)
+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;) {
-		struct tnode *inode = tnode_get_child(tn, --i);
+		struct key_vector *inode = tnode_get_child(tn, --i);
 
 		if (!inode)
 			continue;
@@ -429,27 +430,28 @@ static void update_children(struct tnode *tn)
 	}
 }
 
-static inline void put_child_root(struct tnode *tp, struct trie *t,
-				  t_key key, struct tnode *n)
+static inline void put_child_root(struct key_vector *tp, struct trie *t,
+				  t_key key, struct key_vector *n)
 {
 	if (tp)
 		put_child(tp, get_index(key, tp), n);
 	else
-		rcu_assign_pointer(t->trie, n);
+		rcu_assign_pointer(t->tnode[0], n);
 }
 
-static inline void tnode_free_init(struct tnode *tn)
+static inline void tnode_free_init(struct key_vector *tn)
 {
 	tn->rcu.next = NULL;
 }
 
-static inline void tnode_free_append(struct tnode *tn, struct tnode *n)
+static inline void tnode_free_append(struct key_vector *tn,
+				     struct key_vector *n)
 {
 	n->rcu.next = tn->rcu.next;
 	tn->rcu.next = &n->rcu;
 }
 
-static void tnode_free(struct tnode *tn)
+static void tnode_free(struct key_vector *tn)
 {
 	struct callback_head *head = &tn->rcu;
 
@@ -458,7 +460,7 @@ static void tnode_free(struct tnode *tn)
 		tnode_free_size += TNODE_SIZE(1ul << tn->bits);
 		node_free(tn);
 
-		tn = container_of(head, struct tnode, rcu);
+		tn = container_of(head, struct key_vector, rcu);
 	}
 
 	if (tnode_free_size >= PAGE_SIZE * sync_pages) {
@@ -467,11 +469,12 @@ static void tnode_free(struct tnode *tn)
 	}
 }
 
-static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,
-				    struct tnode *tn)
+static struct key_vector __rcu **replace(struct trie *t,
+					 struct key_vector *oldtnode,
+					 struct key_vector *tn)
 {
-	struct tnode *tp = node_parent(oldtnode);
-	struct tnode **cptr;
+	struct key_vector *tp = node_parent(oldtnode);
+	struct key_vector **cptr;
 	unsigned long i;
 
 	/* setup the parent pointer out of and back into this node */
@@ -485,11 +488,11 @@ static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,
 	tnode_free(oldtnode);
 
 	/* record the pointer that is pointing to this node */
-	cptr = tp ? tp->tnode : &t->trie;
+	cptr = tp ? tp->tnode : t->tnode;
 
 	/* resize children now that oldtnode is freed */
 	for (i = tnode_child_length(tn); i;) {
-		struct tnode *inode = tnode_get_child(tn, --i);
+		struct key_vector *inode = tnode_get_child(tn, --i);
 
 		/* resize child node */
 		if (tnode_full(tn, inode))
@@ -499,9 +502,10 @@ static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,
 	return cptr;
 }
 
-static struct tnode __rcu **inflate(struct trie *t, struct tnode *oldtnode)
+static struct key_vector __rcu **inflate(struct trie *t,
+					 struct key_vector *oldtnode)
 {
-	struct tnode *tn;
+	struct key_vector *tn;
 	unsigned long i;
 	t_key m;
 
@@ -520,8 +524,8 @@ static struct tnode __rcu **inflate(struct trie *t, struct tnode *oldtnode)
 	 * nodes.
 	 */
 	for (i = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
-		struct tnode *inode = tnode_get_child(oldtnode, --i);
-		struct tnode *node0, *node1;
+		struct key_vector *inode = tnode_get_child(oldtnode, --i);
+		struct key_vector *node0, *node1;
 		unsigned long j, k;
 
 		/* An empty child */
@@ -594,9 +598,10 @@ notnode:
 	return NULL;
 }
 
-static struct tnode __rcu **halve(struct trie *t, struct tnode *oldtnode)
+static struct key_vector __rcu **halve(struct trie *t,
+				       struct key_vector *oldtnode)
 {
-	struct tnode *tn;
+	struct key_vector *tn;
 	unsigned long i;
 
 	pr_debug("In halve\n");
@@ -614,9 +619,9 @@ static struct tnode __rcu **halve(struct trie *t, struct tnode *oldtnode)
 	 * nodes.
 	 */
 	for (i = tnode_child_length(oldtnode); i;) {
-		struct tnode *node1 = tnode_get_child(oldtnode, --i);
-		struct tnode *node0 = tnode_get_child(oldtnode, --i);
-		struct tnode *inode;
+		struct key_vector *node1 = tnode_get_child(oldtnode, --i);
+		struct key_vector *node0 = tnode_get_child(oldtnode, --i);
+		struct key_vector *inode;
 
 		/* At least one of the children is empty */
 		if (!node1 || !node0) {
@@ -648,9 +653,9 @@ notnode:
 	return NULL;
 }
 
-static void collapse(struct trie *t, struct tnode *oldtnode)
+static void collapse(struct trie *t, struct key_vector *oldtnode)
 {
-	struct tnode *n, *tp;
+	struct key_vector *n, *tp;
 	unsigned long i;
 
 	/* scan the tnode looking for that one child that might still exist */
@@ -666,7 +671,7 @@ static void collapse(struct trie *t, struct tnode *oldtnode)
 	node_free(oldtnode);
 }
 
-static unsigned char update_suffix(struct tnode *tn)
+static unsigned char update_suffix(struct key_vector *tn)
 {
 	unsigned char slen = tn->pos;
 	unsigned long stride, i;
@@ -677,7 +682,7 @@ static unsigned char update_suffix(struct tnode *tn)
 	 * represent the nodes with suffix length equal to tn->pos
 	 */
 	for (i = 0, stride = 0x2ul ; i < tnode_child_length(tn); i += stride) {
-		struct tnode *n = tnode_get_child(tn, i);
+		struct key_vector *n = tnode_get_child(tn, i);
 
 		if (!n || (n->slen <= slen))
 			continue;
@@ -758,7 +763,7 @@ static unsigned char update_suffix(struct tnode *tn)
  *    tnode_child_length(tn)
  *
  */
-static bool should_inflate(const struct tnode *tp, const struct tnode *tn)
+static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
 {
 	unsigned long used = tnode_child_length(tn);
 	unsigned long threshold = used;
@@ -773,7 +778,7 @@ static bool should_inflate(const struct tnode *tp, const struct tnode *tn)
 	return (used > 1) && tn->pos && ((50 * used) >= threshold);
 }
 
-static bool should_halve(const struct tnode *tp, const struct tnode *tn)
+static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
 {
 	unsigned long used = tnode_child_length(tn);
 	unsigned long threshold = used;
@@ -787,7 +792,7 @@ static bool should_halve(const struct tnode *tp, const struct tnode *tn)
 	return (used > 1) && (tn->bits > 1) && ((100 * used) < threshold);
 }
 
-static bool should_collapse(const struct tnode *tn)
+static inline bool should_collapse(struct key_vector *tn)
 {
 	unsigned long used = tnode_child_length(tn);
 
@@ -802,14 +807,15 @@ static bool should_collapse(const struct tnode *tn)
 }
 
 #define MAX_WORK 10
-static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
+static struct key_vector __rcu **resize(struct trie *t,
+					struct key_vector *tn)
 {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	struct trie_use_stats __percpu *stats = t->stats;
 #endif
-	struct tnode *tp = node_parent(tn);
+	struct key_vector *tp = node_parent(tn);
 	unsigned long cindex = tp ? get_index(tn->key, tp) : 0;
-	struct tnode __rcu **cptr = tp ? tp->tnode : &t->trie;
+	struct key_vector __rcu **cptr = tp ? tp->tnode : t->tnode;
 	int max_work = MAX_WORK;
 
 	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
@@ -825,7 +831,7 @@ static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
 	 * nonempty nodes that are above the threshold.
 	 */
 	while (should_inflate(tp, tn) && max_work) {
-		struct tnode __rcu **tcptr = inflate(t, tn);
+		struct key_vector __rcu **tcptr = inflate(t, tn);
 
 		if (!tcptr) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
@@ -847,7 +853,7 @@ static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
 	 * node is above threshold.
 	 */
 	while (should_halve(tp, tn) && max_work) {
-		struct tnode __rcu **tcptr = halve(t, tn);
+		struct key_vector __rcu **tcptr = halve(t, tn);
 
 		if (!tcptr) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
@@ -882,7 +888,7 @@ static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)
 	return cptr;
 }
 
-static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
+static void leaf_pull_suffix(struct key_vector *tp, struct key_vector *l)
 {
 	while (tp && (tp->slen > tp->pos) && (tp->slen > l->slen)) {
 		if (update_suffix(tp) > l->slen)
@@ -891,7 +897,7 @@ static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
 	}
 }
 
-static void leaf_push_suffix(struct tnode *tn, struct tnode *l)
+static void leaf_push_suffix(struct key_vector *tn, struct key_vector *l)
 {
 	/* if this is a new leaf then tn will be NULL and we can sort
 	 * out parent suffix lengths as a part of trie_rebalance
@@ -903,9 +909,10 @@ static void leaf_push_suffix(struct tnode *tn, struct tnode *l)
 }
 
 /* rcu_read_lock needs to be hold by caller from readside */
-static struct tnode *fib_find_node(struct trie *t, struct tnode **tn, u32 key)
+static struct key_vector *fib_find_node(struct trie *t,
+					struct key_vector **tp, u32 key)
 {
-	struct tnode *pn = NULL, *n = rcu_dereference_rtnl(t->trie);
+	struct key_vector *pn = NULL, *n = rcu_dereference_rtnl(t->tnode[0]);
 
 	while (n) {
 		unsigned long index = get_index(key, n);
@@ -937,7 +944,7 @@ static struct tnode *fib_find_node(struct trie *t, struct tnode **tn, u32 key)
 		n = tnode_get_child_rcu(n, index);
 	}
 
-	*tn = pn;
+	*tp = pn;
 
 	return n;
 }
@@ -967,24 +974,24 @@ static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
 	return NULL;
 }
 
-static void trie_rebalance(struct trie *t, struct tnode *tn)
+static void trie_rebalance(struct trie *t, struct key_vector *tn)
 {
-	struct tnode __rcu **cptr = &t->trie;
+	struct key_vector __rcu **cptr = t->tnode;
 
 	while (tn) {
-		struct tnode *tp = node_parent(tn);
+		struct key_vector *tp = node_parent(tn);
 
 		cptr = resize(t, tn);
 		if (!tp)
 			break;
-		tn = container_of(cptr, struct tnode, tnode[0]);
+		tn = container_of(cptr, struct key_vector, tnode[0]);
 	}
 }
 
-static int fib_insert_node(struct trie *t, struct tnode *tp,
+static int fib_insert_node(struct trie *t, struct key_vector *tp,
 			   struct fib_alias *new, t_key key)
 {
-	struct tnode *n, *l;
+	struct key_vector *n, *l;
 
 	l = leaf_new(key, new);
 	if (!l)
@@ -994,7 +1001,7 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
 	if (tp)
 		n = tnode_get_child(tp, get_index(key, tp));
 	else
-		n = rcu_dereference_rtnl(t->trie);
+		n = rcu_dereference_rtnl(t->tnode[0]);
 
 	/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
 	 *
@@ -1003,7 +1010,7 @@ static int fib_insert_node(struct trie *t, struct tnode *tp,
 	 *  leaves us in position for handling as case 3
 	 */
 	if (n) {
-		struct tnode *tn;
+		struct key_vector *tn;
 
 		tn = tnode_new(key, __fls(key ^ n->key), 1);
 		if (!tn)
@@ -1033,8 +1040,8 @@ noleaf:
 	return -ENOMEM;
 }
 
-static int fib_insert_alias(struct trie *t, struct tnode *tp,
-			    struct tnode *l, struct fib_alias *new,
+static int fib_insert_alias(struct trie *t, struct key_vector *tp,
+			    struct key_vector *l, struct fib_alias *new,
 			    struct fib_alias *fa, t_key key)
 {
 	if (!l)
@@ -1071,7 +1078,7 @@ int fib_table_insert(struct fib_table *tb, struct fib_config *cfg)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct fib_alias *fa, *new_fa;
-	struct tnode *l, *tp;
+	struct key_vector *l, *tp;
 	struct fib_info *fi;
 	u8 plen = cfg->fc_dst_len;
 	u8 slen = KEYLENGTH - plen;
@@ -1215,7 +1222,7 @@ err:
 	return err;
 }
 
-static inline t_key prefix_mismatch(t_key key, struct tnode *n)
+static inline t_key prefix_mismatch(t_key key, struct key_vector *n)
 {
 	t_key prefix = n->key;
 
@@ -1231,12 +1238,12 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 	struct trie_use_stats __percpu *stats = t->stats;
 #endif
 	const t_key key = ntohl(flp->daddr);
-	struct tnode *n, *pn;
+	struct key_vector *n, *pn;
 	struct fib_alias *fa;
 	unsigned long index;
 	t_key cindex;
 
-	n = rcu_dereference(t->trie);
+	n = rcu_dereference(t->tnode[0]);
 	if (!n)
 		return -EAGAIN;
 
@@ -1288,7 +1295,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 	/* Step 2: Sort out leaves and begin backtracing for longest prefix */
 	for (;;) {
 		/* record the pointer where our next node pointer is stored */
-		struct tnode __rcu **cptr = n->tnode;
+		struct key_vector __rcu **cptr = n->tnode;
 
 		/* This test verifies that none of the bits that differ
 		 * between the key and the prefix exist in the region of
@@ -1397,8 +1404,8 @@ found:
 }
 EXPORT_SYMBOL_GPL(fib_table_lookup);
 
-static void fib_remove_alias(struct trie *t, struct tnode *tp,
-			     struct tnode *l, struct fib_alias *old)
+static void fib_remove_alias(struct trie *t, struct key_vector *tp,
+			     struct key_vector *l, struct fib_alias *old)
 {
 	/* record the location of the previous list_info entry */
 	struct hlist_node **pprev = old->fa_list.pprev;
@@ -1431,7 +1438,7 @@ int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
 {
 	struct trie *t = (struct trie *) tb->tb_data;
 	struct fib_alias *fa, *fa_to_delete;
-	struct tnode *l, *tp;
+	struct key_vector *l, *tp;
 	u8 plen = cfg->fc_dst_len;
 	u8 slen = KEYLENGTH - plen;
 	u8 tos = cfg->fc_tos;
@@ -1495,9 +1502,9 @@ int fib_table_delete(struct fib_table *tb, struct fib_config *cfg)
 }
 
 /* Scan for the next leaf starting at the provided key value */
-static struct tnode *leaf_walk_rcu(struct tnode **tn, t_key key)
+static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
 {
-	struct tnode *pn, *n = *tn;
+	struct key_vector *pn, *n = *tn;
 	unsigned long cindex;
 
 	/* record parent node for backtracing */
@@ -1562,14 +1569,14 @@ found:
 int fib_table_flush(struct fib_table *tb)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
+	struct key_vector *n, *pn;
 	struct hlist_node *tmp;
 	struct fib_alias *fa;
-	struct tnode *n, *pn;
 	unsigned long cindex;
 	unsigned char slen;
 	int found = 0;
 
-	n = rcu_dereference(t->trie);
+	n = rcu_dereference(t->tnode[0]);
 	if (!n)
 		goto flush_complete;
 
@@ -1584,7 +1591,7 @@ backtrace:
 		/* walk trie in reverse order */
 		do {
 			while (!(cindex--)) {
-				struct tnode __rcu **cptr;
+				struct key_vector __rcu **cptr;
 				t_key pkey = pn->key;
 
 				n = pn;
@@ -1597,7 +1604,8 @@ backtrace:
 				if (!pn)
 					goto flush_complete;
 
-				pn = container_of(cptr, struct tnode, tnode[0]);
+				pn = container_of(cptr, struct key_vector,
+						  tnode[0]);
 				cindex = get_index(pkey, pn);
 			}
 
@@ -1658,7 +1666,7 @@ void fib_free_table(struct fib_table *tb)
 	call_rcu(&tb->rcu, __trie_free_rcu);
 }
 
-static int fn_trie_dump_leaf(struct tnode *l, struct fib_table *tb,
+static int fn_trie_dump_leaf(struct key_vector *l, struct fib_table *tb,
 			     struct sk_buff *skb, struct netlink_callback *cb)
 {
 	__be32 xkey = htonl(l->key);
@@ -1699,14 +1707,14 @@ int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
 		   struct netlink_callback *cb)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
-	struct tnode *l, *tp;
+	struct key_vector *l, *tp;
 	/* Dump starting at last key.
 	 * Note: 0.0.0.0/0 (ie default) is first key.
 	 */
 	int count = cb->args[2];
 	t_key key = cb->args[3];
 
-	tp = rcu_dereference_rtnl(t->trie);
+	tp = rcu_dereference_rtnl(t->tnode[0]);
 
 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
 		if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
@@ -1759,7 +1767,7 @@ struct fib_table *fib_trie_table(u32 id)
 	tb->tb_num_default = 0;
 
 	t = (struct trie *) tb->tb_data;
-	RCU_INIT_POINTER(t->trie, NULL);
+	RCU_INIT_POINTER(t->tnode[0], NULL);
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	t->stats = alloc_percpu(struct trie_use_stats);
 	if (!t->stats) {
@@ -1776,16 +1784,16 @@ struct fib_table *fib_trie_table(u32 id)
 struct fib_trie_iter {
 	struct seq_net_private p;
 	struct fib_table *tb;
-	struct tnode *tnode;
+	struct key_vector *tnode;
 	unsigned int index;
 	unsigned int depth;
 };
 
-static struct tnode *fib_trie_get_next(struct fib_trie_iter *iter)
+static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
 {
 	unsigned long cindex = iter->index;
-	struct tnode *tn = iter->tnode;
-	struct tnode *p;
+	struct key_vector *tn = iter->tnode;
+	struct key_vector *p;
 
 	/* A single entry routing table */
 	if (!tn)
@@ -1795,7 +1803,7 @@ static struct tnode *fib_trie_get_next(struct fib_trie_iter *iter)
 		 iter->tnode, iter->index, iter->depth);
 rescan:
 	while (cindex < tnode_child_length(tn)) {
-		struct tnode *n = tnode_get_child_rcu(tn, cindex);
+		struct key_vector *n = tnode_get_child_rcu(tn, cindex);
 
 		if (n) {
 			if (IS_LEAF(n)) {
@@ -1826,15 +1834,15 @@ rescan:
 	return NULL;
 }
 
-static struct tnode *fib_trie_get_first(struct fib_trie_iter *iter,
-				       struct trie *t)
+static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
+					     struct trie *t)
 {
-	struct tnode *n;
+	struct key_vector *n;
 
 	if (!t)
 		return NULL;
 
-	n = rcu_dereference(t->trie);
+	n = rcu_dereference(t->tnode[0]);
 	if (!n)
 		return NULL;
 
@@ -1853,7 +1861,7 @@ static struct tnode *fib_trie_get_first(struct fib_trie_iter *iter,
 
 static void trie_collect_stats(struct trie *t, struct trie_stat *s)
 {
-	struct tnode *n;
+	struct key_vector *n;
 	struct fib_trie_iter iter;
 
 	memset(s, 0, sizeof(*s));
@@ -1918,7 +1926,7 @@ static void trie_show_stats(struct seq_file *seq, struct trie_stat *stat)
 	seq_putc(seq, '\n');
 	seq_printf(seq, "\tPointers: %u\n", pointers);
 
-	bytes += sizeof(struct tnode *) * pointers;
+	bytes += sizeof(struct key_vector *) * pointers;
 	seq_printf(seq, "Null ptrs: %u\n", stat->nullpointers);
 	seq_printf(seq, "Total size: %u  kB\n", (bytes + 1023) / 1024);
 }
@@ -2011,7 +2019,7 @@ static const struct file_operations fib_triestat_fops = {
 	.release = single_release_net,
 };
 
-static struct tnode *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
+static struct key_vector *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
 {
 	struct fib_trie_iter *iter = seq->private;
 	struct net *net = seq_file_net(seq);
@@ -2023,7 +2031,7 @@ static struct tnode *fib_trie_get_idx(struct seq_file *seq, loff_t pos)
 		struct fib_table *tb;
 
 		hlist_for_each_entry_rcu(tb, head, tb_hlist) {
-			struct tnode *n;
+			struct key_vector *n;
 
 			for (n = fib_trie_get_first(iter,
 						    (struct trie *) tb->tb_data);
@@ -2052,7 +2060,7 @@ static void *fib_trie_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 	struct fib_table *tb = iter->tb;
 	struct hlist_node *tb_node;
 	unsigned int h;
-	struct tnode *n;
+	struct key_vector *n;
 
 	++*pos;
 	/* next node in same table */
@@ -2138,7 +2146,7 @@ static inline const char *rtn_type(char *buf, size_t len, unsigned int t)
 static int fib_trie_seq_show(struct seq_file *seq, void *v)
 {
 	const struct fib_trie_iter *iter = seq->private;
-	struct tnode *n = v;
+	struct key_vector *n = v;
 
 	if (!node_parent_rcu(n))
 		fib_table_print(seq, iter->tb);
@@ -2200,15 +2208,16 @@ static const struct file_operations fib_trie_fops = {
 struct fib_route_iter {
 	struct seq_net_private p;
 	struct fib_table *main_tb;
-	struct tnode *tnode;
+	struct key_vector *tnode;
 	loff_t	pos;
 	t_key	key;
 };
 
-static struct tnode *fib_route_get_idx(struct fib_route_iter *iter, loff_t pos)
+static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
+					    loff_t pos)
 {
 	struct fib_table *tb = iter->main_tb;
-	struct tnode *l, **tp = &iter->tnode;
+	struct key_vector *l, **tp = &iter->tnode;
 	struct trie *t;
 	t_key key;
 
@@ -2218,7 +2227,7 @@ static struct tnode *fib_route_get_idx(struct fib_route_iter *iter, loff_t pos)
 		key = iter->key;
 	} else {
 		t = (struct trie *)tb->tb_data;
-		iter->tnode = rcu_dereference_rtnl(t->trie);
+		iter->tnode = rcu_dereference_rtnl(t->tnode[0]);
 		iter->pos = 0;
 		key = 0;
 	}
@@ -2264,7 +2273,7 @@ static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
 		return fib_route_get_idx(iter, *pos);
 
 	t = (struct trie *)tb->tb_data;
-	iter->tnode = rcu_dereference_rtnl(t->trie);
+	iter->tnode = rcu_dereference_rtnl(t->tnode[0]);
 	iter->pos = 0;
 	iter->key = 0;
 
@@ -2274,7 +2283,7 @@ static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
 static void *fib_route_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	struct fib_route_iter *iter = seq->private;
-	struct tnode *l = NULL;
+	struct key_vector *l = NULL;
 	t_key key = iter->key;
 
 	++*pos;
@@ -2322,7 +2331,7 @@ static unsigned int fib_flag_trans(int type, __be32 mask, const struct fib_info
 static int fib_route_seq_show(struct seq_file *seq, void *v)
 {
 	struct fib_alias *fa;
-	struct tnode *l = v;
+	struct key_vector *l = v;
 	__be32 prefix;
 
 	if (v == SEQ_START_TOKEN) {

[net-next PATCH 3/9] fib_trie: replace tnode_get_child functions with get_child macros

[Alexander Duyck]

I am replacing the tnode_get_child call with get_child since we are
techically pulling the child out of a key_vector now and not a tnode.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |   58 ++++++++++++++++++++-------------------------------
 1 file changed, 23 insertions(+), 35 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index e8a99c6..c9b24e8 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -158,9 +158,11 @@ static struct kmem_cache *trie_leaf_kmem __read_mostly;
 
 /* caller must hold RTNL */
 #define node_parent(n) rtnl_dereference((n)->parent)
+#define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
 
 /* caller must hold RCU read lock or RTNL */
 #define node_parent_rcu(n) rcu_dereference_rtnl((n)->parent)
+#define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
 
 /* wrapper for rcu_assign_pointer */
 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
@@ -179,20 +181,6 @@ static inline unsigned long tnode_child_length(const struct key_vector *tn)
 	return (1ul << tn->bits) & ~(1ul);
 }
 
-/* caller must hold RTNL */
-static inline struct key_vector *tnode_get_child(struct key_vector *tn,
-						 unsigned long i)
-{
-	return rtnl_dereference(tn->tnode[i]);
-}
-
-/* caller must hold RCU read lock or RTNL */
-static inline struct key_vector *tnode_get_child_rcu(struct key_vector *tn,
-						     unsigned long i)
-{
-	return rcu_dereference_rtnl(tn->tnode[i]);
-}
-
 static inline struct fib_table *trie_get_table(struct trie *t)
 {
 	unsigned long *tb_data = (unsigned long *)t;
@@ -382,7 +370,7 @@ static inline int tnode_full(struct key_vector *tn, struct key_vector *n)
 static void put_child(struct key_vector *tn, unsigned long i,
 		      struct key_vector *n)
 {
-	struct key_vector *chi = tnode_get_child(tn, i);
+	struct key_vector *chi = get_child(tn, i);
 	int isfull, wasfull;
 
 	BUG_ON(i >= tnode_child_length(tn));
@@ -414,7 +402,7 @@ static void update_children(struct key_vector *tn)
 
 	/* update all of the child parent pointers */
 	for (i = tnode_child_length(tn); i;) {
-		struct key_vector *inode = tnode_get_child(tn, --i);
+		struct key_vector *inode = get_child(tn, --i);
 
 		if (!inode)
 			continue;
@@ -492,7 +480,7 @@ static struct key_vector __rcu **replace(struct trie *t,
 
 	/* resize children now that oldtnode is freed */
 	for (i = tnode_child_length(tn); i;) {
-		struct key_vector *inode = tnode_get_child(tn, --i);
+		struct key_vector *inode = get_child(tn, --i);
 
 		/* resize child node */
 		if (tnode_full(tn, inode))
@@ -524,7 +512,7 @@ static struct key_vector __rcu **inflate(struct trie *t,
 	 * nodes.
 	 */
 	for (i = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
-		struct key_vector *inode = tnode_get_child(oldtnode, --i);
+		struct key_vector *inode = get_child(oldtnode, --i);
 		struct key_vector *node0, *node1;
 		unsigned long j, k;
 
@@ -543,8 +531,8 @@ static struct key_vector __rcu **inflate(struct trie *t,
 
 		/* An internal node with two children */
 		if (inode->bits == 1) {
-			put_child(tn, 2 * i + 1, tnode_get_child(inode, 1));
-			put_child(tn, 2 * i, tnode_get_child(inode, 0));
+			put_child(tn, 2 * i + 1, get_child(inode, 1));
+			put_child(tn, 2 * i, get_child(inode, 0));
 			continue;
 		}
 
@@ -574,10 +562,10 @@ static struct key_vector __rcu **inflate(struct trie *t,
 
 		/* populate child pointers in new nodes */
 		for (k = tnode_child_length(inode), j = k / 2; j;) {
-			put_child(node1, --j, tnode_get_child(inode, --k));
-			put_child(node0, j, tnode_get_child(inode, j));
-			put_child(node1, --j, tnode_get_child(inode, --k));
-			put_child(node0, j, tnode_get_child(inode, 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));
+			put_child(node0, j, get_child(inode, j));
 		}
 
 		/* link new nodes to parent */
@@ -619,8 +607,8 @@ static struct key_vector __rcu **halve(struct trie *t,
 	 * nodes.
 	 */
 	for (i = tnode_child_length(oldtnode); i;) {
-		struct key_vector *node1 = tnode_get_child(oldtnode, --i);
-		struct key_vector *node0 = tnode_get_child(oldtnode, --i);
+		struct key_vector *node1 = get_child(oldtnode, --i);
+		struct key_vector *node0 = get_child(oldtnode, --i);
 		struct key_vector *inode;
 
 		/* At least one of the children is empty */
@@ -660,7 +648,7 @@ static void collapse(struct trie *t, struct key_vector *oldtnode)
 
 	/* scan the tnode looking for that one child that might still exist */
 	for (n = NULL, i = tnode_child_length(oldtnode); !n && i;)
-		n = tnode_get_child(oldtnode, --i);
+		n = get_child(oldtnode, --i);
 
 	/* compress one level */
 	tp = node_parent(oldtnode);
@@ -682,7 +670,7 @@ static unsigned char update_suffix(struct key_vector *tn)
 	 * represent the nodes with suffix length equal to tn->pos
 	 */
 	for (i = 0, stride = 0x2ul ; i < tnode_child_length(tn); i += stride) {
-		struct key_vector *n = tnode_get_child(tn, i);
+		struct key_vector *n = get_child(tn, i);
 
 		if (!n || (n->slen <= slen))
 			continue;
@@ -941,7 +929,7 @@ static struct key_vector *fib_find_node(struct trie *t,
 			break;
 
 		pn = n;
-		n = tnode_get_child_rcu(n, index);
+		n = get_child_rcu(n, index);
 	}
 
 	*tp = pn;
@@ -999,7 +987,7 @@ static int fib_insert_node(struct trie *t, struct key_vector *tp,
 
 	/* retrieve child from parent node */
 	if (tp)
-		n = tnode_get_child(tp, get_index(key, tp));
+		n = get_child(tp, get_index(key, tp));
 	else
 		n = rcu_dereference_rtnl(t->tnode[0]);
 
@@ -1287,7 +1275,7 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 			cindex = index;
 		}
 
-		n = tnode_get_child_rcu(n, index);
+		n = get_child_rcu(n, index);
 		if (unlikely(!n))
 			goto backtrace;
 	}
@@ -1526,7 +1514,7 @@ static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
 		cindex = idx;
 
 		/* descend into the next child */
-		n = tnode_get_child_rcu(pn, cindex++);
+		n = get_child_rcu(pn, cindex++);
 	}
 
 	/* this loop will search for the next leaf with a greater key */
@@ -1544,7 +1532,7 @@ static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
 		}
 
 		/* grab the next available node */
-		n = tnode_get_child_rcu(pn, cindex++);
+		n = get_child_rcu(pn, cindex++);
 		if (!n)
 			continue;
 
@@ -1610,7 +1598,7 @@ backtrace:
 			}
 
 			/* grab the next available node */
-			n = tnode_get_child(pn, cindex);
+			n = get_child(pn, cindex);
 		} while (!n);
 	}
 
@@ -1803,7 +1791,7 @@ static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
 		 iter->tnode, iter->index, iter->depth);
 rescan:
 	while (cindex < tnode_child_length(tn)) {
-		struct key_vector *n = tnode_get_child_rcu(tn, cindex);
+		struct key_vector *n = get_child_rcu(tn, cindex);
 
 		if (n) {
 			if (IS_LEAF(n)) {

[net-next PATCH 4/9] fib_trie: Rename tnode_child_length to child_length

[Alexander Duyck]

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 c9b24e8..f06c92e 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;
 
@@ -176,11 +174,18 @@ 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;
@@ -373,7 +378,7 @@ 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)
@@ -401,7 +406,7 @@ 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)
@@ -479,7 +484,7 @@ 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 */
@@ -511,7 +516,7 @@ 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;
@@ -561,7 +566,7 @@ 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));
@@ -606,7 +611,7 @@ 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;
@@ -647,7 +652,7 @@ 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 */
@@ -669,7 +674,7 @@ 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))
@@ -702,12 +707,12 @@ 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.
@@ -717,10 +722,10 @@ 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;
@@ -737,23 +742,23 @@ 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 */
@@ -768,7 +773,7 @@ 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 */
@@ -782,7 +787,7 @@ 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;
 
@@ -1790,7 +1795,7 @@ 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) {

[net-next PATCH 5/9] fib_trie: Add tnode struct as a container for fields not needed in key_vector

[Alexander Duyck]

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>
---
 net/ipv4/fib_trie.c |   72 ++++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 33 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index f06c92e..5e1c469 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -110,7 +110,11 @@ 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
@@ -287,7 +291,7 @@ 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;
 
@@ -316,48 +320,50 @@ 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;
 }
 

Re: [net-next PATCH 5/9] fib_trie: Add tnode struct as a container for fields not needed in key_vector

[Sergei Shtylyov]

Hello.

On 3/6/2015 1:51 AM, Alexander Duyck wrote:

> 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>
> ---
>   net/ipv4/fib_trie.c |   72 ++++++++++++++++++++++++++++-----------------------
>   1 file changed, 39 insertions(+), 33 deletions(-)
>
> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
> index f06c92e..5e1c469 100644
> --- a/net/ipv4/fib_trie.c
> +++ b/net/ipv4/fib_trie.c
[...]
> @@ -316,48 +320,50 @@ static inline void empty_child_dec(struct key_vector *n)
>
>   static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
>   {
[...]
> +	struct tnode *kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
> +	struct key_vector *l = kv->kv;
> +
> +	if (!kv)

    You dereference 'kv' before this check.

[...]
>   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));
>
[...]
> +	pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
>   		 sizeof(struct key_vector *) << bits);
> +
> +	if (!tnode)

    Likewise with 'tnode'.

[...]

WBR, Sergei

Re: [net-next PATCH 5/9] fib_trie: Add tnode struct as a container for fields not needed in key_vector

[Alexander Duyck]

On 03/06/2015 05:17 AM, Sergei Shtylyov wrote:
> Hello.
>
> On 3/6/2015 1:51 AM, Alexander Duyck wrote:
>
>> 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>
>> ---
>>   net/ipv4/fib_trie.c |   72
>> ++++++++++++++++++++++++++++-----------------------
>>   1 file changed, 39 insertions(+), 33 deletions(-)
>>
>> diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
>> index f06c92e..5e1c469 100644
>> --- a/net/ipv4/fib_trie.c
>> +++ b/net/ipv4/fib_trie.c
> [...]
>> @@ -316,48 +320,50 @@ static inline void empty_child_dec(struct
>> key_vector *n)
>>
>>   static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
>>   {
> [...]
>> +    struct tnode *kv = kmem_cache_alloc(trie_leaf_kmem, GFP_KERNEL);
>> +    struct key_vector *l = kv->kv;
>> +
>> +    if (!kv)
>
>    You dereference 'kv' before this check.
>
> [...]
>>   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));
>>
> [...]
>> +    pr_debug("AT %p s=%zu %zu\n", tnode, TNODE_SIZE(0),
>>            sizeof(struct key_vector *) << bits);
>> +
>> +    if (!tnode)
>
>    Likewise with 'tnode'.
>
> [...]
>
> WBR, Sergei

Actually neither of these are a deference.  The 'kv' member is an array
of size 1, so tnode->kv is actually just adding the offset of the array
to the pointer and storing it.  So if tnode is NULL, then tnode->kv is
NULL + 32 on a 64b system.  It isn't really a dereference until I use
the ->, *, or [] operators on the tn pointer.

- Alex

[net-next PATCH 6/9] fib_trie: Move rcu from key_vector to tnode, add accessors.

[Alexander Duyck]

RCU is only needed once for the entire node, not once per key_vector so we
can pull that out and move it to the tnode structure.

In addition add accessors to be used inside the RCU functions so that we
can more easily get from the key vector to either the tnode or the trie
pointers.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |   34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 5e1c469..a9c62f7 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -92,8 +92,6 @@ typedef unsigned int t_key;
 #define IS_LEAF(n) (!(n)->bits)
 
 struct key_vector {
-	struct rcu_head rcu;
-
 	t_key empty_children; /* KEYLENGTH bits needed */
 	t_key full_children;  /* KEYLENGTH bits needed */
 	struct key_vector __rcu *parent;
@@ -111,7 +109,9 @@ struct key_vector {
 };
 
 struct tnode {
+	struct rcu_head rcu;
 	struct key_vector kv[1];
+#define tn_bits kv[0].bits
 };
 
 #define TNODE_SIZE(n)	offsetof(struct tnode, kv[0].tnode[n])
@@ -158,6 +158,11 @@ static const int sync_pages = 128;
 static struct kmem_cache *fn_alias_kmem __read_mostly;
 static struct kmem_cache *trie_leaf_kmem __read_mostly;
 
+static inline struct tnode *tn_info(struct key_vector *kv)
+{
+	return container_of(kv, struct tnode, kv[0]);
+}
+
 /* caller must hold RTNL */
 #define node_parent(n) rtnl_dereference((n)->parent)
 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
@@ -190,13 +195,6 @@ static inline unsigned long get_index(t_key key, struct key_vector *kv)
 	return index >> kv->pos;
 }
 
-static inline struct fib_table *trie_get_table(struct trie *t)
-{
-	unsigned long *tb_data = (unsigned long *)t;
-
-	return container_of(tb_data, struct fib_table, tb_data[0]);
-}
-
 /* To understand this stuff, an understanding of keys and all their bits is
  * necessary. Every node in the trie has a key associated with it, but not
  * all of the bits in that key are significant.
@@ -279,17 +277,17 @@ static inline void alias_free_mem_rcu(struct fib_alias *fa)
 
 static void __node_free_rcu(struct rcu_head *head)
 {
-	struct key_vector *n = container_of(head, struct key_vector, rcu);
+	struct tnode *n = container_of(head, struct tnode, rcu);
 
-	if (IS_LEAF(n))
+	if (!n->tn_bits)
 		kmem_cache_free(trie_leaf_kmem, n);
-	else if (n->bits <= TNODE_KMALLOC_MAX)
+	else if (n->tn_bits <= TNODE_KMALLOC_MAX)
 		kfree(n);
 	else
 		vfree(n);
 }
 
-#define node_free(n) call_rcu(&n->rcu, __node_free_rcu)
+#define node_free(n) call_rcu(&tn_info(n)->rcu, __node_free_rcu)
 
 static struct tnode *tnode_alloc(int bits)
 {
@@ -440,26 +438,26 @@ static inline void put_child_root(struct key_vector *tp, struct trie *t,
 
 static inline void tnode_free_init(struct key_vector *tn)
 {
-	tn->rcu.next = NULL;
+	tn_info(tn)->rcu.next = NULL;
 }
 
 static inline void tnode_free_append(struct key_vector *tn,
 				     struct key_vector *n)
 {
-	n->rcu.next = tn->rcu.next;
-	tn->rcu.next = &n->rcu;
+	tn_info(n)->rcu.next = tn_info(tn)->rcu.next;
+	tn_info(tn)->rcu.next = &tn_info(n)->rcu;
 }
 
 static void tnode_free(struct key_vector *tn)
 {
-	struct callback_head *head = &tn->rcu;
+	struct callback_head *head = &tn_info(tn)->rcu;
 
 	while (head) {
 		head = head->next;
 		tnode_free_size += TNODE_SIZE(1ul << tn->bits);
 		node_free(tn);
 
-		tn = container_of(head, struct key_vector, rcu);
+		tn = container_of(head, struct tnode, rcu)->kv;
 	}
 
 	if (tnode_free_size >= PAGE_SIZE * sync_pages) {

[net-next PATCH 7/9] fib_trie: Pull empty_children and full_children into tnode

[Alexander Duyck]

This pulls the information about the child array out of the key_vector and
places it in the tnode since that is where it is needed.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |   31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index a9c62f7..bd80ed4 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -92,8 +92,6 @@ typedef unsigned int t_key;
 #define IS_LEAF(n) (!(n)->bits)
 
 struct key_vector {
-	t_key empty_children; /* KEYLENGTH bits needed */
-	t_key full_children;  /* KEYLENGTH bits needed */
 	struct key_vector __rcu *parent;
 
 	t_key key;
@@ -110,6 +108,8 @@ struct key_vector {
 
 struct tnode {
 	struct rcu_head rcu;
+	t_key empty_children;		/* KEYLENGTH bits needed */
+	t_key full_children;		/* KEYLENGTH bits needed */
 	struct key_vector kv[1];
 #define tn_bits kv[0].bits
 };
@@ -308,12 +308,12 @@ static struct tnode *tnode_alloc(int bits)
 
 static inline void empty_child_inc(struct key_vector *n)
 {
-	++n->empty_children ? : ++n->full_children;
+	++tn_info(n)->empty_children ? : ++tn_info(n)->full_children;
 }
 
 static inline void empty_child_dec(struct key_vector *n)
 {
-	n->empty_children-- ? : n->full_children--;
+	tn_info(n)->empty_children-- ? : tn_info(n)->full_children--;
 }
 
 static struct key_vector *leaf_new(t_key key, struct fib_alias *fa)
@@ -353,9 +353,9 @@ static struct key_vector *tnode_new(t_key key, int pos, int bits)
 		return NULL;
 
 	if (bits == KEYLENGTH)
-		tn->full_children = 1;
+		tnode->full_children = 1;
 	else
-		tn->empty_children = 1ul << bits;
+		tnode->empty_children = 1ul << bits;
 
 	tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
 	tn->pos = pos;
@@ -395,9 +395,9 @@ static void put_child(struct key_vector *tn, unsigned long i,
 	isfull = tnode_full(tn, n);
 
 	if (wasfull && !isfull)
-		tn->full_children--;
+		tn_info(tn)->full_children--;
 	else if (!wasfull && isfull)
-		tn->full_children++;
+		tn_info(tn)->full_children++;
 
 	if (n && (tn->slen < n->slen))
 		tn->slen = n->slen;
@@ -767,8 +767,8 @@ static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
 
 	/* Keep root node larger */
 	threshold *= tp ? inflate_threshold : inflate_threshold_root;
-	used -= tn->empty_children;
-	used += tn->full_children;
+	used -= tn_info(tn)->empty_children;
+	used += tn_info(tn)->full_children;
 
 	/* if bits == KEYLENGTH then pos = 0, and will fail below */
 
@@ -782,7 +782,7 @@ static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
 
 	/* Keep root node larger */
 	threshold *= tp ? halve_threshold : halve_threshold_root;
-	used -= tn->empty_children;
+	used -= tn_info(tn)->empty_children;
 
 	/* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
 
@@ -793,10 +793,10 @@ static inline bool should_collapse(struct key_vector *tn)
 {
 	unsigned long used = child_length(tn);
 
-	used -= tn->empty_children;
+	used -= tn_info(tn)->empty_children;
 
 	/* account for bits == KEYLENGTH case */
-	if ((tn->bits == KEYLENGTH) && tn->full_children)
+	if ((tn->bits == KEYLENGTH) && tn_info(tn)->full_children)
 		used -= KEY_MAX;
 
 	/* One child or none, time to drop us from the trie */
@@ -1879,7 +1879,7 @@ static void trie_collect_stats(struct trie *t, struct trie_stat *s)
 			s->tnodes++;
 			if (n->bits < MAX_STAT_DEPTH)
 				s->nodesizes[n->bits]++;
-			s->nullpointers += n->empty_children;
+			s->nullpointers += tn_info(n)->empty_children;
 		}
 	}
 	rcu_read_unlock();
@@ -2154,7 +2154,8 @@ static int fib_trie_seq_show(struct seq_file *seq, void *v)
 		seq_indent(seq, iter->depth-1);
 		seq_printf(seq, "  +-- %pI4/%zu %u %u %u\n",
 			   &prf, KEYLENGTH - n->pos - n->bits, n->bits,
-			   n->full_children, n->empty_children);
+			   tn_info(n)->full_children,
+			   tn_info(n)->empty_children);
 	} else {
 		__be32 val = htonl(n->key);
 		struct fib_alias *fa;

[net-next PATCH 8/9] fib_trie: Move parent from key_vector to tnode

[Alexander Duyck]

This change pulls the parent pointer from the key_vector and places it in
the tnode structure.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index bd80ed4..578ee89 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -92,8 +92,6 @@ typedef unsigned int t_key;
 #define IS_LEAF(n) (!(n)->bits)
 
 struct key_vector {
-	struct key_vector __rcu *parent;
-
 	t_key key;
 	unsigned char pos;		/* 2log(KEYLENGTH) bits needed */
 	unsigned char bits;		/* 2log(KEYLENGTH) bits needed */
@@ -110,6 +108,7 @@ struct tnode {
 	struct rcu_head rcu;
 	t_key empty_children;		/* KEYLENGTH bits needed */
 	t_key full_children;		/* KEYLENGTH bits needed */
+	struct key_vector __rcu *parent;
 	struct key_vector kv[1];
 #define tn_bits kv[0].bits
 };
@@ -164,21 +163,21 @@ static inline struct tnode *tn_info(struct key_vector *kv)
 }
 
 /* caller must hold RTNL */
-#define node_parent(n) rtnl_dereference((n)->parent)
+#define node_parent(tn) rtnl_dereference(tn_info(tn)->parent)
 #define get_child(tn, i) rtnl_dereference((tn)->tnode[i])
 
 /* caller must hold RCU read lock or RTNL */
-#define node_parent_rcu(n) rcu_dereference_rtnl((n)->parent)
+#define node_parent_rcu(tn) rcu_dereference_rtnl(tn_info(tn)->parent)
 #define get_child_rcu(tn, i) rcu_dereference_rtnl((tn)->tnode[i])
 
 /* wrapper for rcu_assign_pointer */
 static inline void node_set_parent(struct key_vector *n, struct key_vector *tp)
 {
 	if (n)
-		rcu_assign_pointer(n->parent, tp);
+		rcu_assign_pointer(tn_info(n)->parent, tp);
 }
 
-#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER((n)->parent, p)
+#define NODE_INIT_PARENT(n, p) RCU_INIT_POINTER(tn_info(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.

[net-next PATCH 9/9] fib_trie: Add key vector to root, return parent key_vector in resize

[Alexander Duyck]

This change makes it so that the root of the trie contains a key_vector, by
doing this we make room to essentially collapse the entire trie by at least
one cache line as we can store the information about the tnode or leaf that
is pointed to in the root.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
---
 net/ipv4/fib_trie.c |  367 +++++++++++++++++++++++----------------------------
 1 file changed, 169 insertions(+), 198 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 578ee89..86f2d50 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -88,8 +88,9 @@
 
 typedef unsigned int t_key;
 
-#define IS_TNODE(n) ((n)->bits)
-#define IS_LEAF(n) (!(n)->bits)
+#define IS_TRIE(n)	((n)->pos >= KEYLENGTH)
+#define IS_TNODE(n)	((n)->bits)
+#define IS_LEAF(n)	(!(n)->bits)
 
 struct key_vector {
 	t_key key;
@@ -138,13 +139,13 @@ struct trie_stat {
 };
 
 struct trie {
-	struct key_vector __rcu *tnode[1];
+	struct key_vector kv[1];
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	struct trie_use_stats __percpu *stats;
 #endif
 };
 
-static struct key_vector **resize(struct trie *t, struct key_vector *tn);
+static struct key_vector *resize(struct trie *t, struct key_vector *tn);
 static size_t tnode_free_size;
 
 /*
@@ -187,10 +188,15 @@ static inline unsigned long child_length(const struct key_vector *tn)
 	return (1ul << tn->bits) & ~(1ul);
 }
 
+#define get_cindex(key, kv) (((key) ^ (kv)->key) >> (kv)->pos)
+
 static inline unsigned long get_index(t_key key, struct key_vector *kv)
 {
 	unsigned long index = key ^ kv->key;
 
+	if ((BITS_PER_LONG <= KEYLENGTH) && (KEYLENGTH == kv->pos))
+		return 0;
+
 	return index >> kv->pos;
 }
 
@@ -426,13 +432,13 @@ static void update_children(struct key_vector *tn)
 	}
 }
 
-static inline void put_child_root(struct key_vector *tp, struct trie *t,
-				  t_key key, struct key_vector *n)
+static inline void put_child_root(struct key_vector *tp, t_key key,
+				  struct key_vector *n)
 {
-	if (tp)
-		put_child(tp, get_index(key, tp), n);
+	if (IS_TRIE(tp))
+		rcu_assign_pointer(tp->tnode[0], n);
 	else
-		rcu_assign_pointer(t->tnode[0], n);
+		put_child(tp, get_index(key, tp), n);
 }
 
 static inline void tnode_free_init(struct key_vector *tn)
@@ -465,17 +471,16 @@ static void tnode_free(struct key_vector *tn)
 	}
 }
 
-static struct key_vector __rcu **replace(struct trie *t,
-					 struct key_vector *oldtnode,
-					 struct key_vector *tn)
+static struct key_vector *replace(struct trie *t,
+				  struct key_vector *oldtnode,
+				  struct key_vector *tn)
 {
 	struct key_vector *tp = node_parent(oldtnode);
-	struct key_vector **cptr;
 	unsigned long i;
 
 	/* setup the parent pointer out of and back into this node */
 	NODE_INIT_PARENT(tn, tp);
-	put_child_root(tp, t, tn->key, tn);
+	put_child_root(tp, tn->key, tn);
 
 	/* update all of the child parent pointers */
 	update_children(tn);
@@ -483,23 +488,20 @@ static struct key_vector __rcu **replace(struct trie *t,
 	/* all pointers should be clean so we are done */
 	tnode_free(oldtnode);
 
-	/* record the pointer that is pointing to this node */
-	cptr = tp ? tp->tnode : t->tnode;
-
 	/* resize children now that oldtnode is freed */
 	for (i = child_length(tn); i;) {
 		struct key_vector *inode = get_child(tn, --i);
 
 		/* resize child node */
 		if (tnode_full(tn, inode))
-			resize(t, inode);
+			tn = resize(t, inode);
 	}
 
-	return cptr;
+	return tp;
 }
 
-static struct key_vector __rcu **inflate(struct trie *t,
-					 struct key_vector *oldtnode)
+static struct key_vector *inflate(struct trie *t,
+				  struct key_vector *oldtnode)
 {
 	struct key_vector *tn;
 	unsigned long i;
@@ -594,8 +596,8 @@ notnode:
 	return NULL;
 }
 
-static struct key_vector __rcu **halve(struct trie *t,
-				       struct key_vector *oldtnode)
+static struct key_vector *halve(struct trie *t,
+				struct key_vector *oldtnode)
 {
 	struct key_vector *tn;
 	unsigned long i;
@@ -649,7 +651,8 @@ notnode:
 	return NULL;
 }
 
-static void collapse(struct trie *t, struct key_vector *oldtnode)
+static struct key_vector *collapse(struct trie *t,
+				   struct key_vector *oldtnode)
 {
 	struct key_vector *n, *tp;
 	unsigned long i;
@@ -660,11 +663,13 @@ static void collapse(struct trie *t, struct key_vector *oldtnode)
 
 	/* compress one level */
 	tp = node_parent(oldtnode);
-	put_child_root(tp, t, oldtnode->key, n);
+	put_child_root(tp, oldtnode->key, n);
 	node_set_parent(n, tp);
 
 	/* drop dead node */
 	node_free(oldtnode);
+
+	return tp;
 }
 
 static unsigned char update_suffix(struct key_vector *tn)
@@ -765,7 +770,7 @@ static inline bool should_inflate(struct key_vector *tp, struct key_vector *tn)
 	unsigned long threshold = used;
 
 	/* Keep root node larger */
-	threshold *= tp ? inflate_threshold : inflate_threshold_root;
+	threshold *= IS_TRIE(tp) ? inflate_threshold_root : inflate_threshold;
 	used -= tn_info(tn)->empty_children;
 	used += tn_info(tn)->full_children;
 
@@ -780,7 +785,7 @@ static inline bool should_halve(struct key_vector *tp, struct key_vector *tn)
 	unsigned long threshold = used;
 
 	/* Keep root node larger */
-	threshold *= tp ? halve_threshold : halve_threshold_root;
+	threshold *= IS_TRIE(tp) ? halve_threshold_root : halve_threshold;
 	used -= tn_info(tn)->empty_children;
 
 	/* if bits == KEYLENGTH then used = 100% on wrap, and will fail below */
@@ -803,15 +808,13 @@ static inline bool should_collapse(struct key_vector *tn)
 }
 
 #define MAX_WORK 10
-static struct key_vector __rcu **resize(struct trie *t,
-					struct key_vector *tn)
+static struct key_vector *resize(struct trie *t, struct key_vector *tn)
 {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	struct trie_use_stats __percpu *stats = t->stats;
 #endif
 	struct key_vector *tp = node_parent(tn);
-	unsigned long cindex = tp ? get_index(tn->key, tp) : 0;
-	struct key_vector __rcu **cptr = tp ? tp->tnode : t->tnode;
+	unsigned long cindex = get_index(tn->key, tp);
 	int max_work = MAX_WORK;
 
 	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
@@ -821,15 +824,14 @@ static struct key_vector __rcu **resize(struct trie *t,
 	 * doing it ourselves.  This way we can let RCU fully do its
 	 * thing without us interfering
 	 */
-	BUG_ON(tn != rtnl_dereference(cptr[cindex]));
+	BUG_ON(tn != get_child(tp, cindex));
 
 	/* Double as long as the resulting node has a number of
 	 * nonempty nodes that are above the threshold.
 	 */
 	while (should_inflate(tp, tn) && max_work) {
-		struct key_vector __rcu **tcptr = inflate(t, tn);
-
-		if (!tcptr) {
+		tp = inflate(t, tn);
+		if (!tp) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 			this_cpu_inc(stats->resize_node_skipped);
 #endif
@@ -837,21 +839,19 @@ static struct key_vector __rcu **resize(struct trie *t,
 		}
 
 		max_work--;
-		cptr = tcptr;
-		tn = rtnl_dereference(cptr[cindex]);
+		tn = get_child(tp, cindex);
 	}
 
 	/* Return if at least one inflate is run */
 	if (max_work != MAX_WORK)
-		return cptr;
+		return node_parent(tn);
 
 	/* Halve as long as the number of empty children in this
 	 * node is above threshold.
 	 */
 	while (should_halve(tp, tn) && max_work) {
-		struct key_vector __rcu **tcptr = halve(t, tn);
-
-		if (!tcptr) {
+		tp = halve(t, tn);
+		if (!tp) {
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 			this_cpu_inc(stats->resize_node_skipped);
 #endif
@@ -859,34 +859,34 @@ static struct key_vector __rcu **resize(struct trie *t,
 		}
 
 		max_work--;
-		cptr = tcptr;
-		tn = rtnl_dereference(cptr[cindex]);
+		tn = get_child(tp, cindex);
 	}
 
 	/* Only one child remains */
-	if (should_collapse(tn)) {
-		collapse(t, tn);
-		return cptr;
-	}
+	if (should_collapse(tn))
+		return collapse(t, tn);
+
+	/* update parent in case inflate or halve failed */
+	tp = node_parent(tn);
 
 	/* Return if at least one deflate was run */
 	if (max_work != MAX_WORK)
-		return cptr;
+		return tp;
 
 	/* push the suffix length to the parent node */
 	if (tn->slen > tn->pos) {
 		unsigned char slen = update_suffix(tn);
 
-		if (tp && (slen > tp->slen))
+		if (slen > tp->slen)
 			tp->slen = slen;
 	}
 
-	return cptr;
+	return tp;
 }
 
 static void leaf_pull_suffix(struct key_vector *tp, struct key_vector *l)
 {
-	while (tp && (tp->slen > tp->pos) && (tp->slen > l->slen)) {
+	while ((tp->slen > tp->pos) && (tp->slen > l->slen)) {
 		if (update_suffix(tp) > l->slen)
 			break;
 		tp = node_parent(tp);
@@ -898,7 +898,7 @@ static void leaf_push_suffix(struct key_vector *tn, struct key_vector *l)
 	/* if this is a new leaf then tn will be NULL and we can sort
 	 * out parent suffix lengths as a part of trie_rebalance
 	 */
-	while (tn && (tn->slen < l->slen)) {
+	while (tn->slen < l->slen) {
 		tn->slen = l->slen;
 		tn = node_parent(tn);
 	}
@@ -908,10 +908,17 @@ static void leaf_push_suffix(struct key_vector *tn, struct key_vector *l)
 static struct key_vector *fib_find_node(struct trie *t,
 					struct key_vector **tp, u32 key)
 {
-	struct key_vector *pn = NULL, *n = rcu_dereference_rtnl(t->tnode[0]);
+	struct key_vector *pn, *n = t->kv;
+	unsigned long index = 0;
+
+	do {
+		pn = n;
+		n = get_child_rcu(n, index);
 
-	while (n) {
-		unsigned long index = get_index(key, n);
+		if (!n)
+			break;
+
+		index = get_cindex(key, n);
 
 		/* This bit of code is a bit tricky but it combines multiple
 		 * checks into a single check.  The prefix consists of the
@@ -932,13 +939,8 @@ static struct key_vector *fib_find_node(struct trie *t,
 			break;
 		}
 
-		/* we have found a leaf. Prefixes have already been compared */
-		if (IS_LEAF(n))
-			break;
-
-		pn = n;
-		n = get_child_rcu(n, index);
-	}
+		/* keep searching until we find a perfect match leaf or NULL */
+	} while (IS_TNODE(n));
 
 	*tp = pn;
 
@@ -972,16 +974,8 @@ static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen,
 
 static void trie_rebalance(struct trie *t, struct key_vector *tn)
 {
-	struct key_vector __rcu **cptr = t->tnode;
-
-	while (tn) {
-		struct key_vector *tp = node_parent(tn);
-
-		cptr = resize(t, tn);
-		if (!tp)
-			break;
-		tn = container_of(cptr, struct key_vector, tnode[0]);
-	}
+	while (!IS_TRIE(tn))
+		tn = resize(t, tn);
 }
 
 static int fib_insert_node(struct trie *t, struct key_vector *tp,
@@ -994,10 +988,7 @@ static int fib_insert_node(struct trie *t, struct key_vector *tp,
 		goto noleaf;
 
 	/* retrieve child from parent node */
-	if (tp)
-		n = get_child(tp, get_index(key, tp));
-	else
-		n = rcu_dereference_rtnl(t->tnode[0]);
+	n = get_child(tp, get_index(key, tp));
 
 	/* Case 2: n is a LEAF or a TNODE and the key doesn't match.
 	 *
@@ -1017,7 +1008,7 @@ static int fib_insert_node(struct trie *t, struct key_vector *tp,
 		put_child(tn, get_index(key, tn) ^ 1, n);
 
 		/* start adding routes into the node */
-		put_child_root(tp, t, key, tn);
+		put_child_root(tp, key, tn);
 		node_set_parent(n, tn);
 
 		/* parent now has a NULL spot where the leaf can go */
@@ -1026,7 +1017,7 @@ static int fib_insert_node(struct trie *t, struct key_vector *tp,
 
 	/* Case 3: n is NULL, and will just insert a new leaf */
 	NODE_INIT_PARENT(l, tp);
-	put_child_root(tp, t, key, l);
+	put_child_root(tp, key, l);
 	trie_rebalance(t, tp);
 
 	return 0;
@@ -1239,7 +1230,10 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 	unsigned long index;
 	t_key cindex;
 
-	n = rcu_dereference(t->tnode[0]);
+	pn = t->kv;
+	cindex = 0;
+
+	n = get_child_rcu(pn, cindex);
 	if (!n)
 		return -EAGAIN;
 
@@ -1247,12 +1241,9 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
 	this_cpu_inc(stats->gets);
 #endif
 
-	pn = n;
-	cindex = 0;
-
 	/* Step 1: Travel to the longest prefix match in the trie */
 	for (;;) {
-		index = get_index(key, n);
+		index = get_cindex(key, n);
 
 		/* This bit of code is a bit tricky but it combines multiple
 		 * checks into a single check.  The prefix consists of the
@@ -1323,13 +1314,17 @@ backtrace:
 			while (!cindex) {
 				t_key pkey = pn->key;
 
-				pn = node_parent_rcu(pn);
-				if (unlikely(!pn))
+				/* If we don't have a parent then there is
+				 * nothing for us to do as we do not have any
+				 * further nodes to parse.
+				 */
+				if (IS_TRIE(pn))
 					return -EAGAIN;
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 				this_cpu_inc(stats->backtrack);
 #endif
 				/* Get Child's index */
+				pn = node_parent_rcu(pn);
 				cindex = get_index(pkey, pn);
 			}
 
@@ -1414,7 +1409,7 @@ static void fib_remove_alias(struct trie *t, struct key_vector *tp,
 	 * out parent suffix lengths as a part of trie_rebalance
 	 */
 	if (hlist_empty(&l->leaf)) {
-		put_child_root(tp, t, l->key, NULL);
+		put_child_root(tp, l->key, NULL);
 		node_free(l);
 		trie_rebalance(t, tp);
 		return;
@@ -1503,38 +1498,32 @@ static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
 	struct key_vector *pn, *n = *tn;
 	unsigned long cindex;
 
-	/* record parent node for backtracing */
-	pn = n;
-	cindex = n ? get_index(key, n) : 0;
-
 	/* this loop is meant to try and find the key in the trie */
-	while (n) {
-		unsigned long idx = get_index(key, n);
-
-		/* guarantee forward progress on the keys */
-		if (IS_LEAF(n) && (n->key >= key))
-			goto found;
-		if (idx >= (1ul << n->bits))
-			break;
-
+	do {
 		/* record parent and next child index */
 		pn = n;
-		cindex = idx;
+		cindex = get_index(key, pn);
+
+		if (cindex >> pn->bits)
+			break;
 
 		/* descend into the next child */
 		n = get_child_rcu(pn, cindex++);
-	}
+		if (!n)
+			break;
+
+		/* guarantee forward progress on the keys */
+		if (IS_LEAF(n) && (n->key >= key))
+			goto found;
+	} while (IS_TNODE(n));
 
 	/* this loop will search for the next leaf with a greater key */
-	while (pn) {
+	while (!IS_TRIE(pn)) {
 		/* if we exhausted the parent node we will need to climb */
 		if (cindex >= (1ul << pn->bits)) {
 			t_key pkey = pn->key;
 
 			pn = node_parent_rcu(pn);
-			if (!pn)
-				break;
-
 			cindex = get_index(pkey, pn) + 1;
 			continue;
 		}
@@ -1557,7 +1546,7 @@ static struct key_vector *leaf_walk_rcu(struct key_vector **tn, t_key key)
 	return NULL; /* Root of trie */
 found:
 	/* if we are at the limit for keys just return NULL for the tnode */
-	*tn = (n->key == KEY_MAX) ? NULL : pn;
+	*tn = pn;
 	return n;
 }
 
@@ -1565,83 +1554,70 @@ found:
 int fib_table_flush(struct fib_table *tb)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
-	struct key_vector *n, *pn;
+	struct key_vector *pn = t->kv;
+	unsigned long cindex = 1;
 	struct hlist_node *tmp;
 	struct fib_alias *fa;
-	unsigned long cindex;
-	unsigned char slen;
 	int found = 0;
 
-	n = rcu_dereference(t->tnode[0]);
-	if (!n)
-		goto flush_complete;
+	/* walk trie in reverse order */
+	for (;;) {
+		unsigned char slen = 0;
+		struct key_vector *n;
 
-	pn = NULL;
-	cindex = 0;
+		if (!(cindex--)) {
+			t_key pkey = pn->key;
 
-	while (IS_TNODE(n)) {
-		/* record pn and cindex for leaf walking */
-		pn = n;
-		cindex = 1ul << n->bits;
-backtrace:
-		/* walk trie in reverse order */
-		do {
-			while (!(cindex--)) {
-				struct key_vector __rcu **cptr;
-				t_key pkey = pn->key;
+			/* cannot resize the trie vector */
+			if (IS_TRIE(pn))
+				break;
 
-				n = pn;
-				pn = node_parent(n);
+			/* resize completed node */
+			pn = resize(t, pn);
+			cindex = get_index(pkey, pn);
 
-				/* resize completed node */
-				cptr = resize(t, n);
+			continue;
+		}
 
-				/* if we got the root we are done */
-				if (!pn)
-					goto flush_complete;
+		/* grab the next available node */
+		n = get_child(pn, cindex);
+		if (!n)
+			continue;
 
-				pn = container_of(cptr, struct key_vector,
-						  tnode[0]);
-				cindex = get_index(pkey, pn);
-			}
+		if (IS_TNODE(n)) {
+			/* record pn and cindex for leaf walking */
+			pn = n;
+			cindex = 1ul << n->bits;
 
-			/* grab the next available node */
-			n = get_child(pn, cindex);
-		} while (!n);
-	}
+			continue;
+		}
 
-	/* track slen in case any prefixes survive */
-	slen = 0;
+		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
+			struct fib_info *fi = fa->fa_info;
 
-	hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
-		struct fib_info *fi = fa->fa_info;
+			if (fi && (fi->fib_flags & RTNH_F_DEAD)) {
+				hlist_del_rcu(&fa->fa_list);
+				fib_release_info(fa->fa_info);
+				alias_free_mem_rcu(fa);
+				found++;
 
-		if (fi && (fi->fib_flags & RTNH_F_DEAD)) {
-			hlist_del_rcu(&fa->fa_list);
-			fib_release_info(fa->fa_info);
-			alias_free_mem_rcu(fa);
-			found++;
+				continue;
+			}
 
-			continue;
+			slen = fa->fa_slen;
 		}
 
-		slen = fa->fa_slen;
-	}
-
-	/* update leaf slen */
-	n->slen = slen;
+		/* update leaf slen */
+		n->slen = slen;
 
-	if (hlist_empty(&n->leaf)) {
-		put_child_root(pn, t, n->key, NULL);
-		node_free(n);
-	} else {
-		leaf_pull_suffix(pn, n);
+		if (hlist_empty(&n->leaf)) {
+			put_child_root(pn, n->key, NULL);
+			node_free(n);
+		} else {
+			leaf_pull_suffix(pn, n);
+		}
 	}
 
-	/* if trie is leaf only loop is completed */
-	if (pn)
-		goto backtrace;
-flush_complete:
 	pr_debug("trie_flush found=%d\n", found);
 	return found;
 }
@@ -1703,15 +1679,13 @@ int fib_table_dump(struct fib_table *tb, struct sk_buff *skb,
 		   struct netlink_callback *cb)
 {
 	struct trie *t = (struct trie *)tb->tb_data;
-	struct key_vector *l, *tp;
+	struct key_vector *l, *tp = t->kv;
 	/* Dump starting at last key.
 	 * Note: 0.0.0.0/0 (ie default) is first key.
 	 */
 	int count = cb->args[2];
 	t_key key = cb->args[3];
 
-	tp = rcu_dereference_rtnl(t->tnode[0]);
-
 	while ((l = leaf_walk_rcu(&tp, key)) != NULL) {
 		if (fn_trie_dump_leaf(l, tb, skb, cb) < 0) {
 			cb->args[3] = key;
@@ -1747,14 +1721,12 @@ void __init fib_trie_init(void)
 					   0, SLAB_PANIC, NULL);
 }
 
-
 struct fib_table *fib_trie_table(u32 id)
 {
 	struct fib_table *tb;
 	struct trie *t;
 
-	tb = kmalloc(sizeof(struct fib_table) + sizeof(struct trie),
-		     GFP_KERNEL);
+	tb = kzalloc(sizeof(*tb) + sizeof(struct trie), GFP_KERNEL);
 	if (tb == NULL)
 		return NULL;
 
@@ -1763,7 +1735,8 @@ struct fib_table *fib_trie_table(u32 id)
 	tb->tb_num_default = 0;
 
 	t = (struct trie *) tb->tb_data;
-	RCU_INIT_POINTER(t->tnode[0], NULL);
+	t->kv[0].pos = KEYLENGTH;
+	t->kv[0].slen = KEYLENGTH;
 #ifdef CONFIG_IP_FIB_TRIE_STATS
 	t->stats = alloc_percpu(struct trie_use_stats);
 	if (!t->stats) {
@@ -1788,57 +1761,55 @@ struct fib_trie_iter {
 static struct key_vector *fib_trie_get_next(struct fib_trie_iter *iter)
 {
 	unsigned long cindex = iter->index;
-	struct key_vector *tn = iter->tnode;
-	struct key_vector *p;
-
-	/* A single entry routing table */
-	if (!tn)
-		return NULL;
+	struct key_vector *pn = iter->tnode;
+	t_key pkey;
 
 	pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
 		 iter->tnode, iter->index, iter->depth);
-rescan:
-	while (cindex < child_length(tn)) {
-		struct key_vector *n = get_child_rcu(tn, cindex);
 
-		if (n) {
+	while (!IS_TRIE(pn)) {
+		while (cindex < child_length(pn)) {
+			struct key_vector *n = get_child_rcu(pn, cindex++);
+
+			if (!n)
+				continue;
+
 			if (IS_LEAF(n)) {
-				iter->tnode = tn;
-				iter->index = cindex + 1;
+				iter->tnode = pn;
+				iter->index = cindex;
 			} else {
 				/* push down one level */
 				iter->tnode = n;
 				iter->index = 0;
 				++iter->depth;
 			}
+
 			return n;
 		}
 
-		++cindex;
-	}
-
-	/* Current node exhausted, pop back up */
-	p = node_parent_rcu(tn);
-	if (p) {
-		cindex = get_index(tn->key, p) + 1;
-		tn = p;
+		/* Current node exhausted, pop back up */
+		pkey = pn->key;
+		pn = node_parent_rcu(pn);
+		cindex = get_index(pkey, pn) + 1;
 		--iter->depth;
-		goto rescan;
 	}
 
-	/* got root? */
+	/* record root node so further searches know we are done */
+	iter->tnode = pn;
+	iter->index = 0;
+
 	return NULL;
 }
 
 static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
 					     struct trie *t)
 {
-	struct key_vector *n;
+	struct key_vector *n, *pn = t->kv;
 
 	if (!t)
 		return NULL;
 
-	n = rcu_dereference(t->tnode[0]);
+	n = rcu_dereference(pn->tnode[0]);
 	if (!n)
 		return NULL;
 
@@ -1847,7 +1818,7 @@ static struct key_vector *fib_trie_get_first(struct fib_trie_iter *iter,
 		iter->index = 0;
 		iter->depth = 1;
 	} else {
-		iter->tnode = NULL;
+		iter->tnode = pn;
 		iter->index = 0;
 		iter->depth = 0;
 	}
@@ -2144,7 +2115,7 @@ static int fib_trie_seq_show(struct seq_file *seq, void *v)
 	const struct fib_trie_iter *iter = seq->private;
 	struct key_vector *n = v;
 
-	if (!node_parent_rcu(n))
+	if (IS_TRIE(node_parent_rcu(n)))
 		fib_table_print(seq, iter->tb);
 
 	if (IS_TNODE(n)) {
@@ -2224,7 +2195,7 @@ static struct key_vector *fib_route_get_idx(struct fib_route_iter *iter,
 		key = iter->key;
 	} else {
 		t = (struct trie *)tb->tb_data;
-		iter->tnode = rcu_dereference_rtnl(t->tnode[0]);
+		iter->tnode = t->kv;
 		iter->pos = 0;
 		key = 0;
 	}
@@ -2270,7 +2241,7 @@ static void *fib_route_seq_start(struct seq_file *seq, loff_t *pos)
 		return fib_route_get_idx(iter, *pos);
 
 	t = (struct trie *)tb->tb_data;
-	iter->tnode = rcu_dereference_rtnl(t->tnode[0]);
+	iter->tnode = t->kv;
 	iter->pos = 0;
 	iter->key = 0;