[PATCH] add b+tree library

Johannes Berg
2009-01-10T10:46:37Z

This adds a b+tree library. The API and memory layout is documented in
the header file lib/btree.h. There are tree versions for 32, 64 and
128 bit keys as well as unsigned long (32/64 depending on platform).

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
---
We've tested this code in userspace, and would appreciate still getting
it into 2.6.29 because we're working on two separate users for 2.6.30
and it's easier to manage that way. We do not expect API changes before
using it, as the code using these trees is almost finished but not well
enough tested for .29.

MAINTAINERS | 8
include/linux/btree-128.h | 109 ++++++
include/linux/btree-type.h | 147 ++++++++
include/linux/btree.h | 243 +++++++++++++
lib/Kconfig | 3
lib/Makefile | 1
lib/btree.c | 797 +++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 1308 insertions(+)

--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ wireless-testing/include/linux/btree.h 2009-01-10 11:41:46.000000000 +0100
@@ -0,0 +1,243 @@
+#ifndef BTREE_H
+#define BTREE_H
+
+#include <linux/kernel.h>
+#include <linux/mempool.h>
+
+/**
+ * DOC: B+Tree basics
+ *
+ * A B+Tree is a data structure for looking up arbitrary (currently allowing
+ * unsigned long, u32, u64 and 2 * u64) keys into pointers. The data structure
+ * is described at http://en.wikipedia.org/wiki/B-tree, we currently do not
+ * use binary search to find the key on lookups.
+ *
+ * Each B+Tree consists of a head, that contains bookkeeping information and
+ * a variable number (starting with zero) nodes. Each node contains the keys
+ * and pointers to sub-nodes, or, for leaf nodes, the keys and values for the
+ * tree entries.
+ *
+ * Each node in this implementation has the following layout:
+ * [key1, key2, ..., keyN] [val1, val2, ..., valN]
+ *
+ * Each key here is an array of unsigned longs, geo->no_longs in total. The
+ * number of keys and values (N) is geo->no_pairs.
+ */
+
+/**
+ * struct btree_head - btree head
+ *
+ * @node: the first node in the tree
+ * @mempool: mempool used for node allocations
+ * @height: current of the tree
+ */
+struct btree_head {
+ unsigned long *node;
+ mempool_t *mempool;
+ int height;
+};
+
+/* btree geometry */
+struct btree_geo;
+
+/**
+ * btree_alloc - allocate function for the mempool
+ * @gfp_mask: gfp mask for the allocation
+ * @pool_data: unused
+ */
+void *btree_alloc(gfp_t gfp_mask, void *pool_data);
+
+/**
+ * btree_free - free function for the mempool
+ * @element: the element to free
+ * @pool_data: unused
+ */
+void btree_free(void *element, void *pool_data);
+
+/**
+ * btree_init_mempool - initialise a btree with given mempool
+ *
+ * @head: the btree head to initialise
+ * @mempool: the mempool to use
+ *
+ * When this function is used, there is no need to destroy
+ * the mempool.
+ */
+void btree_init_mempool(struct btree_head *head, mempool_t *mempool);
+
+/**
+ * btree_init - initialise a btree
+ *
+ * @head: the btree head to initialise
+ *
+ * This function allocates the memory pool that the
+ * btree needs. Returns zero or a negative error code
+ * (-%ENOMEM) when memory allocation fails.
+ *
+ */
+int __must_check btree_init(struct btree_head *head);
+
+/**
+ * btree_destroy - destroy mempool
+ *
+ * @head: the btree head to destroy
+ *
+ * This function destroys the internal memory pool, use only
+ * when using btree_init(), not with btree_init_mempool().
+ */
+void btree_destroy(struct btree_head *head);
+
+/**
+ * btree_lookup - look up a key in the btree
+ *
+ * @head: the btree to look in
+ * @geo: the btree geometry
+ * @key: the key to look up
+ *
+ * This function returns the value for the given key, or %NULL.
+ */
+void *btree_lookup(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key);
+
+/**
+ * btree_insert - insert an entry into the btree
+ *
+ * @head: the btree to add to
+ * @geo: the btree geometry
+ * @key: the key to add (must not already be present)
+ * @val: the value to add (must not be %NULL)
+ * @gfp: allocation flags for node allocations
+ *
+ * This function returns 0 if the item could be added, or an
+ * error code if it failed (may fail due to memory pressure).
+ */
+int __must_check btree_insert(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, void *val, gfp_t gfp);
+/**
+ * btree_update - update an entry in the btree
+ *
+ * @head: the btree to update
+ * @geo: the btree geometry
+ * @key: the key to update
+ * @val: the value to change it to (must not be %NULL)
+ *
+ * This function returns 0 if the update was successful, or
+ * -%ENOENT if the key could not be found.
+ */
+int btree_update(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, void *val);
+/**
+ * btree_remove - remove an entry from the btree
+ *
+ * @head: the btree to update
+ * @geo: the btree geometry
+ * @key: the key to remove
+ *
+ * This function returns the removed entry, or %NULL if the key
+ * could not be found.
+ */
+void *btree_remove(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key);
+
+/**
+ * btree_merge - merge two btrees
+ *
+ * @target: the tree that gets all the entries
+ * @victim: the tree that gets merged into @target
+ * @geo: the btree geometry
+ * @gfp: allocation flags
+ *
+ * The two trees @target and @victim may not contain the same keys,
+ * that is a bug and triggers a BUG(). This function returns zero
+ * if the trees were merged successfully, and may return a failure
+ * when memory allocation fails, in which case both trees might have
+ * been partially merged, i.e. some entries have been moved from
+ * @victim to @target.
+ */
+int btree_merge(struct btree_head *target, struct btree_head *victim,
+ struct btree_geo *geo, gfp_t gfp);
+
+/**
+ * btree_last - get last entry in btree
+ *
+ * @head: btree head
+ * @geo: btree geometry
+ * @key: last key
+ *
+ * Returns the last entry in the btree, and sets @key to the key
+ * of that entry; returns NULL if the tree is empty, in that case
+ * key is not changed.
+ */
+void *btree_last(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key);
+
+/**
+ * btree_get_prev - get previous entry
+ *
+ * @head: btree head
+ * @geo: btree geometry
+ * @key: pointer to key
+ *
+ * The function returns the next item right before the value pointed to by
+ * @key, and updates @key with its key, or returns %NULL when there is no
+ * entry with a key smaller than the given key.
+ */
+void *btree_get_prev(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key);
+
+
+/* internal use, use btree_visitor{l,32,64,128} */
+size_t btree_visitor(struct btree_head *head, struct btree_geo *geo,
+ unsigned long opaque,
+ void (*func)(void *elem, unsigned long opaque,
+ unsigned long *key, size_t index,
+ void *func2),
+ void *func2);
+
+/* internal use, use btree_grim_visitor{l,32,64,128} */
+size_t btree_grim_visitor(struct btree_head *head, struct btree_geo *geo,
+ unsigned long opaque,
+ void (*func)(void *elem, unsigned long opaque,
+ unsigned long *key,
+ size_t index, void *func2),
+ void *func2);
+
+
+#include <linux/btree-128.h>
+
+extern struct btree_geo btree_geo32;
+#define BTREE_TYPE_SUFFIX l
+#define BTREE_TYPE_BITS BITS_PER_LONG
+#define BTREE_TYPE_GEO &btree_geo32
+#define BTREE_KEYTYPE unsigned long
+#include <linux/btree-type.h>
+
+#define btree_for_each_safel(head, key, val) \
+ for (val = btree_lastl(head, &key); \
+ val; \
+ val = btree_get_prevl(head, &key))
+
+#define BTREE_TYPE_SUFFIX 32
+#define BTREE_TYPE_BITS 32
+#define BTREE_TYPE_GEO &btree_geo32
+#define BTREE_KEYTYPE u32
+#include <linux/btree-type.h>
+
+#define btree_for_each_safe32(head, key, val) \
+ for (val = btree_last32(head, &key); \
+ val; \
+ val = btree_get_prev32(head, &key))
+
+extern struct btree_geo btree_geo64;
+#define BTREE_TYPE_SUFFIX 64
+#define BTREE_TYPE_BITS 64
+#define BTREE_TYPE_GEO &btree_geo64
+#define BTREE_KEYTYPE u64
+#include <linux/btree-type.h>
+
+#define btree_for_each_safe64(head, key, val) \
+ for (val = btree_last64(head, &key); \
+ val; \
+ val = btree_get_prev64(head, &key))
+
+#endif
--- wireless-testing.orig/lib/Kconfig 2009-01-10 10:46:42.000000000 +0100
+++ wireless-testing/lib/Kconfig 2009-01-10 11:40:54.000000000 +0100
@@ -136,6 +136,9 @@ config TEXTSEARCH_FSM
config PLIST
boolean

+config BTREE
+ tristate
+
config HAS_IOMEM
boolean
depends on !NO_IOMEM
--- wireless-testing.orig/lib/Makefile 2009-01-10 10:46:42.000000000 +0100
+++ wireless-testing/lib/Makefile 2009-01-10 11:27:11.000000000 +0100
@@ -40,6 +40,7 @@ lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += f
obj-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
obj-$(CONFIG_PLIST) += plist.o
+obj-$(CONFIG_BTREE) += btree.o
obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
obj-$(CONFIG_DEBUG_LIST) += list_debug.o
obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ wireless-testing/lib/btree.c 2009-01-10 11:41:47.000000000 +0100
@@ -0,0 +1,797 @@
+/*
+ * lib/btree.c - Simple In-memory B+Tree
+ *
+ * As should be obvious for Linux kernel code, license is GPLv2
+ *
+ * Copyright (c) 2007-2008 Joern Engel <joern@logfs.org>
+ * Bits and pieces stolen from Peter Zijlstra's code, which is
+ * Copyright 2007, Red Hat Inc. Peter Zijlstra <pzijlstr@redhat.com>
+ * GPLv2
+ *
+ * see http://programming.kicks-ass.net/kernel-patches/vma_lookup/btree.patch
+ *
+ * A relatively simple B+Tree implementation. I have written it as a learning
+ * excercise to understand how B+Trees work. Turned out to be useful as well.
+ *
+ * B+Trees can be used similar to Linux radix trees (which don't have anything
+ * in common with textbook radix trees, beware). Prerequisite for them working
+ * well is that access to a random tree node is much faster than a large number
+ * of operations within each node.
+ *
+ * Disks have fulfilled the prerequisite for a long time. More recently DRAM
+ * has gained similar properties, as memory access times, when measured in cpu
+ * cycles, have increased. Cacheline sizes have increased as well, which also
+ * helps B+Trees.
+ *
+ * Compared to radix trees, B+Trees are more efficient when dealing with a
+ * sparsely populated address space. Between 25% and 50% of the memory is
+ * occupied with valid pointers. When densely populated, radix trees contain
+ * ~98% pointers - hard to beat. Very sparse radix trees contain only ~2%
+ * pointers.
+ *
+ * This particular implementation stores pointers identified by a long value.
+ * Storing NULL pointers is illegal, lookup will return NULL when no entry
+ * was found.
+ *
+ * A tricks was used that is not commonly found in textbooks. The lowest
+ * values are to the right, not to the left. All used slots within a node
+ * are on the left, all unused slots contain NUL values. Most operations
+ * simply loop once over all slots and terminate on the first NUL.
+ */
+
+#include <linux/btree.h>
+#include <linux/cache.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define NODESIZE MAX(L1_CACHE_BYTES, 128)
+
+struct btree_geo {
+ int keylen;
+ int no_pairs;
+ int no_longs;
+};
+
+struct btree_geo btree_geo32 = {
+ .keylen = 1,
+ .no_pairs = NODESIZE / sizeof(long) / 2,
+ .no_longs = NODESIZE / sizeof(long) / 2,
+};
+EXPORT_SYMBOL_GPL(btree_geo32);
+
+#define LONG_PER_U64 (64 / BITS_PER_LONG)
+struct btree_geo btree_geo64 = {
+ .keylen = LONG_PER_U64,
+ .no_pairs = NODESIZE / sizeof(long) / (1 + LONG_PER_U64),
+ .no_longs = LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + LONG_PER_U64)),
+};
+EXPORT_SYMBOL_GPL(btree_geo64);
+
+struct btree_geo btree_geo128 = {
+ .keylen = 2 * LONG_PER_U64,
+ .no_pairs = NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64),
+ .no_longs = 2 * LONG_PER_U64 * (NODESIZE / sizeof(long) / (1 + 2 * LONG_PER_U64)),
+};
+EXPORT_SYMBOL_GPL(btree_geo128);
+
+static struct kmem_cache *btree_cachep;
+
+void *btree_alloc(gfp_t gfp_mask, void *pool_data)
+{
+ return kmem_cache_alloc(btree_cachep, gfp_mask);
+}
+EXPORT_SYMBOL_GPL(btree_alloc);
+
+void btree_free(void *element, void *pool_data)
+{
+ kmem_cache_free(btree_cachep, element);
+}
+EXPORT_SYMBOL_GPL(btree_free);
+
+static unsigned long *btree_node_alloc(struct btree_head *head, gfp_t gfp)
+{
+ unsigned long *node;
+
+ node = mempool_alloc(head->mempool, gfp);
+ memset(node, 0, NODESIZE);
+ return node;
+}
+
+static int longcmp(const unsigned long *l1, const unsigned long *l2, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++) {
+ if (l1[i] < l2[i])
+ return -1;
+ if (l1[i] > l2[i])
+ return 1;
+ }
+ return 0;
+}
+
+static unsigned long *longcpy(unsigned long *dest, const unsigned long *src,
+ size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++)
+ dest[i] = src[i];
+ return dest;
+}
+
+static unsigned long *longset(unsigned long *s, unsigned long c, size_t n)
+{
+ size_t i;
+
+ for (i = 0; i < n; i++)
+ s[i] = c;
+ return s;
+}
+
+static void dec_key(struct btree_geo *geo, unsigned long *key)
+{
+ unsigned long val;
+ int i;
+
+ for (i = geo->keylen - 1; i >= 0; i--) {
+ val = key[i];
+ key[i] = val - 1;
+ if (val)
+ break;
+ }
+}
+
+static unsigned long *bkey(struct btree_geo *geo, unsigned long *node, int n)
+{
+ return &node[n * geo->keylen];
+}
+
+static void *bval(struct btree_geo *geo, unsigned long *node, int n)
+{
+ return (void *)node[geo->no_longs + n];
+}
+
+static void setkey(struct btree_geo *geo, unsigned long *node, int n,
+ unsigned long *key)
+{
+ longcpy(bkey(geo, node, n), key, geo->keylen);
+}
+
+static void setval(struct btree_geo *geo, unsigned long *node, int n,
+ void *val)
+{
+ node[geo->no_longs + n] = (unsigned long) val;
+}
+
+static void clearpair(struct btree_geo *geo, unsigned long *node, int n)
+{
+ longset(bkey(geo, node, n), 0, geo->keylen);
+ node[geo->no_longs + n] = 0;
+}
+
+static inline void __btree_init(struct btree_head *head)
+{
+ head->node = NULL;
+ head->height = 0;
+}
+
+void btree_init_mempool(struct btree_head *head, mempool_t *mempool)
+{
+ __btree_init(head);
+ head->mempool = mempool;
+}
+EXPORT_SYMBOL_GPL(btree_init_mempool);
+
+int btree_init(struct btree_head *head)
+{
+ __btree_init(head);
+ head->mempool = mempool_create(0, btree_alloc, btree_free, NULL);
+ if (!head->mempool)
+ return -ENOMEM;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(btree_init);
+
+void btree_destroy(struct btree_head *head)
+{
+ mempool_destroy(head->mempool);
+ head->mempool = NULL;
+}
+EXPORT_SYMBOL_GPL(btree_destroy);
+
+void *btree_last(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key)
+{
+ int height = head->height;
+ unsigned long *node = head->node;
+
+ if (height == 0)
+ return NULL;
+
+ for ( ; height > 1; height--)
+ node = bval(geo, node, 0);
+
+ longcpy(key, bkey(geo, node, 0), geo->keylen);
+ return bval(geo, node, 0);
+}
+EXPORT_SYMBOL_GPL(btree_last);
+
+static int keycmp(struct btree_geo *geo, unsigned long *node, int pos,
+ unsigned long *key)
+{
+ return longcmp(bkey(geo, node, pos), key, geo->keylen);
+}
+
+static int keyzero(struct btree_geo *geo, unsigned long *key)
+{
+ int i;
+
+ for (i = 0; i < geo->keylen; i++)
+ if (key[i])
+ return 0;
+
+ return 1;
+}
+
+void *btree_lookup(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key)
+{
+ int i, height = head->height;
+ unsigned long *node = head->node;
+
+ if (height == 0)
+ return NULL;
+
+ for ( ; height > 1; height--) {
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) <= 0)
+ break;
+ if (i == geo->no_pairs)
+ return NULL;
+ node = bval(geo, node, i);
+ if (!node)
+ return NULL;
+ }
+
+ if (!node)
+ return NULL;
+
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) == 0)
+ return bval(geo, node, i);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(btree_lookup);
+
+int btree_update(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, void *val)
+{
+ int i, height = head->height;
+ unsigned long *node = head->node;
+
+ if (height == 0)
+ return -ENOENT;
+
+ for ( ; height > 1; height--) {
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) <= 0)
+ break;
+ if (i == geo->no_pairs)
+ return -ENOENT;
+ node = bval(geo, node, i);
+ if (!node)
+ return -ENOENT;
+ }
+
+ if (!node)
+ return -ENOENT;
+
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) == 0) {
+ setval(geo, node, i, val);
+ return 0;
+ }
+ return -ENOENT;
+}
+EXPORT_SYMBOL_GPL(btree_update);
+
+/*
+ * Usually this function is quite similar to normal lookup. But the key of
+ * a parent node may be smaller than the smallest key of all its siblings.
+ * In such a case we cannot just return NULL, as we have only proven that no
+ * key smaller than __key, but larger than this parent key exists.
+ * So we set __key to the parent key and retry. We have to use the smallest
+ * such parent key, which is the last parent key we encountered.
+ */
+void *btree_get_prev(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *__key)
+{
+ int i, height;
+ unsigned long *node, *oldnode;
+ unsigned long *retry_key = NULL, key[geo->keylen];
+
+ if (keyzero(geo, __key))
+ return NULL;
+
+ if (head->height == 0)
+ return NULL;
+retry:
+ longcpy(key, __key, geo->keylen);
+ dec_key(geo, key);
+
+ node = head->node;
+ for (height = head->height ; height > 1; height--) {
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) <= 0)
+ break;
+ if (i == geo->no_pairs)
+ goto miss;
+ oldnode = node;
+ node = bval(geo, node, i);
+ if (!node)
+ goto miss;
+ retry_key = bkey(geo, oldnode, i);
+ }
+
+ if (!node)
+ goto miss;
+
+ for (i = 0; i < geo->no_pairs; i++) {
+ if (keycmp(geo, node, i, key) <= 0) {
+ if (bval(geo, node, i)) {
+ longcpy(__key, bkey(geo, node, i), geo->keylen);
+ return bval(geo, node, i);
+ } else
+ goto miss;
+ }
+ }
+miss:
+ if (retry_key) {
+ __key = retry_key;
+ retry_key = NULL;
+ goto retry;
+ }
+ return NULL;
+}
+
+static int getpos(struct btree_geo *geo, unsigned long *node,
+ unsigned long *key)
+{
+ int i;
+
+ for (i = 0; i < geo->no_pairs; i++) {
+ if (keycmp(geo, node, i, key) <= 0)
+ break;
+ }
+ return i;
+}
+
+static int getfill(struct btree_geo *geo, unsigned long *node, int start)
+{
+ int i;
+
+ for (i = start; i < geo->no_pairs; i++)
+ if (!bval(geo, node, i))
+ break;
+ return i;
+}
+
+/*
+ * locate the correct leaf node in the btree
+ */
+static unsigned long *find_level(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, int level)
+{
+ unsigned long *node = head->node;
+ int i, height;
+
+ for (height = head->height; height > level; height--) {
+ for (i = 0; i < geo->no_pairs; i++)
+ if (keycmp(geo, node, i, key) <= 0)
+ break;
+
+ if ((i == geo->no_pairs) || !bval(geo, node, i)) {
+ /* right-most key is too large, update it */
+ /* FIXME: If the right-most key on higher levels is
+ * always zero, this wouldn't be necessary. */
+ i--;
+ setkey(geo, node, i, key);
+ }
+ BUG_ON(i < 0);
+ node = bval(geo, node, i);
+ }
+ BUG_ON(!node);
+ return node;
+}
+
+static int btree_grow(struct btree_head *head, struct btree_geo *geo,
+ gfp_t gfp)
+{
+ unsigned long *node;
+ int fill;
+
+ node = btree_node_alloc(head, gfp);
+ if (!node)
+ return -ENOMEM;
+ if (head->node) {
+ fill = getfill(geo, head->node, 0);
+ setkey(geo, node, 0, bkey(geo, head->node, fill - 1));
+ setval(geo, node, 0, head->node);
+ }
+ head->node = node;
+ head->height++;
+ return 0;
+}
+
+static void btree_shrink(struct btree_head *head, struct btree_geo *geo)
+{
+ unsigned long *node;
+ int fill;
+
+ if (head->height <= 1)
+ return;
+
+ node = head->node;
+ fill = getfill(geo, node, 0);
+ BUG_ON(fill > 1);
+ head->node = bval(geo, node, 0);
+ head->height--;
+ mempool_free(node, head->mempool);
+}
+
+static int btree_insert_level(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, void *val, int level,
+ gfp_t gfp)
+{
+ unsigned long *node;
+ int i, pos, fill, err;
+
+ BUG_ON(!val);
+ if (head->height < level) {
+ err = btree_grow(head, geo, gfp);
+ if (err)
+ return err;
+ }
+
+retry:
+ node = find_level(head, geo, key, level);
+ pos = getpos(geo, node, key);
+ fill = getfill(geo, node, pos);
+ /* two identical keys are not allowed */
+ BUG_ON(pos < fill && keycmp(geo, node, pos, key) == 0);
+
+ if (fill == geo->no_pairs) {
+ /* need to split node */
+ unsigned long *new;
+
+ new = btree_node_alloc(head, gfp);
+ if (!new)
+ return -ENOMEM;
+ err = btree_insert_level(head, geo,
+ bkey(geo, node, fill / 2 - 1),
+ new, level + 1, gfp);
+ if (err) {
+ mempool_free(new, head->mempool);
+ return err;
+ }
+ for (i = 0; i < fill / 2; i++) {
+ setkey(geo, new, i, bkey(geo, node, i));
+ setval(geo, new, i, bval(geo, node, i));
+ setkey(geo, node, i, bkey(geo, node, i + fill / 2));
+ setval(geo, node, i, bval(geo, node, i + fill / 2));
+ clearpair(geo, node, i + fill / 2);
+ }
+ if (fill & 1) {
+ setkey(geo, node, i, bkey(geo, node, fill - 1));
+ setval(geo, node, i, bval(geo, node, fill - 1));
+ clearpair(geo, node, fill - 1);
+ }
+ goto retry;
+ }
+ BUG_ON(fill >= geo->no_pairs);
+
+ /* shift and insert */
+ for (i = fill; i > pos; i--) {
+ setkey(geo, node, i, bkey(geo, node, i - 1));
+ setval(geo, node, i, bval(geo, node, i - 1));
+ }
+ setkey(geo, node, pos, key);
+ setval(geo, node, pos, val);
+
+ return 0;
+}
+
+int btree_insert(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, void *val, gfp_t gfp)
+{
+ return btree_insert_level(head, geo, key, val, 1, gfp);
+}
+EXPORT_SYMBOL_GPL(btree_insert);
+
+static void *btree_remove_level(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, int level);
+static void merge(struct btree_head *head, struct btree_geo *geo, int level,
+ unsigned long *left, int lfill,
+ unsigned long *right, int rfill,
+ unsigned long *parent, int lpos)
+{
+ int i;
+
+ for (i = 0; i < rfill; i++) {
+ /* Move all keys to the left */
+ setkey(geo, left, lfill + i, bkey(geo, right, i));
+ setval(geo, left, lfill + i, bval(geo, right, i));
+ }
+ /* Exchange left and right child in parent */
+ setval(geo, parent, lpos, right);
+ setval(geo, parent, lpos + 1, left);
+ /* Remove left (formerly right) child from parent */
+ btree_remove_level(head, geo, bkey(geo, parent, lpos), level + 1);
+ mempool_free(right, head->mempool);
+}
+
+static void rebalance(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, int level, unsigned long *child, int fill)
+{
+ unsigned long *parent, *left = NULL, *right = NULL;
+ int i, no_left, no_right;
+
+ if (fill == 0) {
+ /* Because we don't steal entries from a neigbour, this case
+ * can happen. Parent node contains a single child, this
+ * node, so merging with a sibling never happens.
+ */
+ btree_remove_level(head, geo, key, level + 1);
+ mempool_free(child, head->mempool);
+ return;
+ }
+
+ parent = find_level(head, geo, key, level + 1);
+ i = getpos(geo, parent, key);
+ BUG_ON(bval(geo, parent, i) != child);
+
+ if (i > 0) {
+ left = bval(geo, parent, i - 1);
+ no_left = getfill(geo, left, 0);
+ if (fill + no_left <= geo->no_pairs) {
+ merge(head, geo, level,
+ left, no_left,
+ child, fill,
+ parent, i - 1);
+ return;
+ }
+ }
+ if (i + 1 < getfill(geo, parent, i)) {
+ right = bval(geo, parent, i + 1);
+ no_right = getfill(geo, right, 0);
+ if (fill + no_right <= geo->no_pairs) {
+ merge(head, geo, level,
+ child, fill,
+ right, no_right,
+ parent, i);
+ return;
+ }
+ }
+ /*
+ * We could also try to steal one entry from the left or right
+ * neighbor. By not doing so we changed the invariant from
+ * "all nodes are at least half full" to "no two neighboring
+ * nodes can be merged". Which means that the average fill of
+ * all nodes is still half or better.
+ */
+}
+
+static void *btree_remove_level(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key, int level)
+{
+ unsigned long *node;
+ int i, pos, fill;
+ void *ret;
+
+ if (level > head->height) {
+ /* we recursed all the way up */
+ head->height = 0;
+ head->node = NULL;
+ return NULL;
+ }
+
+ node = find_level(head, geo, key, level);
+ pos = getpos(geo, node, key);
+ fill = getfill(geo, node, pos);
+ if ((level == 1) && (keycmp(geo, node, pos, key) != 0))
+ return NULL;
+ ret = bval(geo, node, pos);
+
+ /* remove and shift */
+ for (i = pos; i < fill - 1; i++) {
+ setkey(geo, node, i, bkey(geo, node, i + 1));
+ setval(geo, node, i, bval(geo, node, i + 1));
+ }
+ clearpair(geo, node, fill - 1);
+
+ if (fill - 1 < geo->no_pairs / 2) {
+ if (level < head->height)
+ rebalance(head, geo, key, level, node, fill - 1);
+ else if (fill - 1 == 1)
+ btree_shrink(head, geo);
+ }
+
+ return ret;
+}
+
+void *btree_remove(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *key)
+{
+ if (head->height == 0)
+ return NULL;
+
+ return btree_remove_level(head, geo, key, 1);
+}
+EXPORT_SYMBOL_GPL(btree_remove);
+
+int btree_merge(struct btree_head *target, struct btree_head *victim,
+ struct btree_geo *geo, gfp_t gfp)
+{
+ unsigned long key[geo->keylen];
+ unsigned long dup[geo->keylen];
+ void *val;
+ int err;
+
+ BUG_ON(target == victim);
+
+ if (!(target->node)) {
+ /* target is empty, just copy fields over */
+ target->node = victim->node;
+ target->height = victim->height;
+ __btree_init(victim);
+ return 0;
+ }
+
+ /* TODO: This needs some optimizations. Currently we do three tree
+ * walks to remove a single object from the victim.
+ */
+ for (;;) {
+ if (!btree_last(victim, geo, key))
+ break;
+ val = btree_lookup(victim, geo, key);
+ err = btree_insert(target, geo, key, val, gfp);
+ if (err)
+ return err;
+ /* We must make a copy of the key, as the original will get
+ * mangled inside btree_remove. */
+ longcpy(dup, key, geo->keylen);
+ btree_remove(victim, geo, dup);
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(btree_merge);
+
+static size_t __btree_for_each(struct btree_head *head, struct btree_geo *geo,
+ unsigned long *node, unsigned long opaque,
+ void (*func)(void *elem, unsigned long opaque,
+ unsigned long *key, size_t index,
+ void *func2),
+ void *func2, int reap, int height, size_t count)
+{
+ int i;
+ unsigned long *child;
+
+ for (i = 0; i < geo->no_pairs; i++) {
+ child = bval(geo, node, i);
+ if (!child)
+ break;
+ if (height > 1)
+ count = __btree_for_each(head, geo, child, opaque,
+ func, func2, reap, height - 1, count);
+ else
+ func(child, opaque, bkey(geo, node, i), count++,
+ func2);
+ }
+ if (reap)
+ mempool_free(node, head->mempool);
+ return count;
+}
+
+static void empty(void *elem, unsigned long opaque, unsigned long *key,
+ size_t index, void *func2)
+{
+}
+
+void visitorl(void *elem, unsigned long opaque, unsigned long *key,
+ size_t index, void *__func)
+{
+ visitorl_t func = __func;
+
+ func(elem, opaque, *key, index);
+}
+EXPORT_SYMBOL_GPL(visitorl);
+
+void visitor32(void *elem, unsigned long opaque, unsigned long *__key,
+ size_t index, void *__func)
+{
+ visitor32_t func = __func;
+ u32 *key = (void *)__key;
+
+ func(elem, opaque, *key, index);
+}
+EXPORT_SYMBOL_GPL(visitor32);
+
+void visitor64(void *elem, unsigned long opaque, unsigned long *__key,
+ size_t index, void *__func)
+{
+ visitor64_t func = __func;
+ u64 *key = (void *)__key;
+
+ func(elem, opaque, *key, index);
+}
+EXPORT_SYMBOL_GPL(visitor64);
+
+void visitor128(void *elem, unsigned long opaque, unsigned long *__key,
+ size_t index, void *__func)
+{
+ visitor128_t func = __func;
+ u64 *key = (void *)__key;
+
+ func(elem, opaque, key[0], key[1], index);
+}
+EXPORT_SYMBOL_GPL(visitor128);
+
+size_t btree_visitor(struct btree_head *head, struct btree_geo *geo,
+ unsigned long opaque,
+ void (*func)(void *elem, unsigned long opaque,
+ unsigned long *key,
+ size_t index, void *func2),
+ void *func2)
+{
+ size_t count = 0;
+
+ if (!func2)
+ func = empty;
+ if (head->node)
+ count = __btree_for_each(head, geo, head->node, opaque, func,
+ func2, 0, head->height, 0);
+ return count;
+}
+EXPORT_SYMBOL_GPL(btree_visitor);
+
+size_t btree_grim_visitor(struct btree_head *head, struct btree_geo *geo,
+ unsigned long opaque,
+ void (*func)(void *elem, unsigned long opaque,
+ unsigned long *key,
+ size_t index, void *func2),
+ void *func2)
+{
+ size_t count = 0;
+
+ if (!func2)
+ func = empty;
+ if (head->node)
+ count = __btree_for_each(head, geo, head->node, opaque, func,
+ func2, 1, head->height, 0);
+ __btree_init(head);
+ return count;
+}
+EXPORT_SYMBOL_GPL(btree_grim_visitor);
+
+static int __init btree_module_init(void)
+{
+ btree_cachep = kmem_cache_create("btree_node", NODESIZE, 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+ return 0;
+}
+
+static void __exit btree_module_exit(void)
+{
+ kmem_cache_destroy(btree_cachep);
+}
+
+/* If core code starts using btree, initialization should happen even earlier */
+module_init(btree_module_init);
+module_exit(btree_module_exit);
+
+MODULE_AUTHOR("Joern Engel <joern@logfs.org>");
+MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
+MODULE_LICENSE("GPL");
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ wireless-testing/include/linux/btree-128.h 2009-01-10 11:41:47.000000000 +0100
@@ -0,0 +1,109 @@
+extern struct btree_geo btree_geo128;
+
+struct btree_head128 { struct btree_head h; };
+
+static inline void btree_init_mempool128(struct btree_head128 *head,
+ mempool_t *mempool)
+{
+ btree_init_mempool(&head->h, mempool);
+}
+
+static inline int btree_init128(struct btree_head128 *head)
+{
+ return btree_init(&head->h);
+}
+
+static inline void btree_destroy128(struct btree_head128 *head)
+{
+ btree_destroy(&head->h);
+}
+
+static inline void *btree_lookup128(struct btree_head128 *head, u64 k1, u64 k2)
+{
+ u64 key[2] = {k1, k2};
+ return btree_lookup(&head->h, &btree_geo128, (unsigned long *)&key);
+}
+
+static inline void *btree_get_prev128(struct btree_head128 *head,
+ u64 *k1, u64 *k2)
+{
+ u64 key[2] = {*k1, *k2};
+ void *val;
+
+ val = btree_get_prev(&head->h, &btree_geo128,
+ (unsigned long *)&key);
+ *k1 = key[0];
+ *k2 = key[1];
+ return val;
+}
+
+static inline int btree_insert128(struct btree_head128 *head, u64 k1, u64 k2,
+ void *val, gfp_t gfp)
+{
+ u64 key[2] = {k1, k2};
+ return btree_insert(&head->h, &btree_geo128,
+ (unsigned long *)&key, val, gfp);
+}
+
+static inline int btree_update128(struct btree_head128 *head, u64 k1, u64 k2,
+ void *val)
+{
+ u64 key[2] = {k1, k2};
+ return btree_update(&head->h, &btree_geo128,
+ (unsigned long *)&key, val);
+}
+
+static inline void *btree_remove128(struct btree_head128 *head, u64 k1, u64 k2)
+{
+ u64 key[2] = {k1, k2};
+ return btree_remove(&head->h, &btree_geo128, (unsigned long *)&key);
+}
+
+static inline void *btree_last128(struct btree_head128 *head, u64 *k1, u64 *k2)
+{
+ u64 key[2];
+ void *val;
+
+ val = btree_last(&head->h, &btree_geo128, (unsigned long *)&key[0]);
+ if (val) {
+ *k1 = key[0];
+ *k2 = key[1];
+ }
+
+ return val;
+}
+
+static inline int btree_merge128(struct btree_head128 *target,
+ struct btree_head128 *victim,
+ gfp_t gfp)
+{
+ return btree_merge(&target->h, &victim->h, &btree_geo128, gfp);
+}
+
+void visitor128(void *elem, unsigned long opaque, unsigned long *__key,
+ size_t index, void *__func);
+
+typedef void (*visitor128_t)(void *elem, unsigned long opaque,
+ u64 key1, u64 key2, size_t index);
+
+static inline size_t btree_visitor128(struct btree_head128 *head,
+ unsigned long opaque,
+ visitor128_t func2)
+{
+ return btree_visitor(&head->h, &btree_geo128, opaque,
+ visitor128, func2);
+}
+
+static inline size_t btree_grim_visitor128(struct btree_head128 *head,
+ unsigned long opaque,
+ visitor128_t func2)
+{
+ return btree_grim_visitor(&head->h, &btree_geo128, opaque,
+ visitor128, func2);
+}
+
+#define btree_for_each_safe128(head, k1, k2, val) \
+ for (val = btree_last128(head, &k1, &k2); \
+ val; \
+ val = btree_get_prev128(head, &k1, &k2))
+
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ wireless-testing/include/linux/btree-type.h 2009-01-10 11:41:47.000000000 +0100
@@ -0,0 +1,147 @@
+#define __BTREE_TP(pfx, type, sfx) pfx ## type ## sfx
+#define _BTREE_TP(pfx, type, sfx) __BTREE_TP(pfx, type, sfx)
+#define BTREE_TP(pfx) _BTREE_TP(pfx, BTREE_TYPE_SUFFIX,)
+#define BTREE_FN(name) BTREE_TP(btree_ ## name)
+#define BTREE_TYPE_HEAD BTREE_TP(struct btree_head)
+#define VISITOR_FN BTREE_TP(visitor)
+#define VISITOR_FN_T _BTREE_TP(visitor, BTREE_TYPE_SUFFIX, _t)
+
+BTREE_TYPE_HEAD {
+ struct btree_head h;
+};
+
+static inline void BTREE_FN(init_mempool)(BTREE_TYPE_HEAD *head,
+ mempool_t *mempool)
+{
+ btree_init_mempool(&head->h, mempool);
+}
+
+static inline int BTREE_FN(init)(BTREE_TYPE_HEAD *head)
+{
+ return btree_init(&head->h);
+}
+
+static inline void BTREE_FN(destroy)(BTREE_TYPE_HEAD *head)
+{
+ btree_destroy(&head->h);
+}
+
+static inline int BTREE_FN(merge)(BTREE_TYPE_HEAD *target,
+ BTREE_TYPE_HEAD *victim,
+ gfp_t gfp)
+{
+ return btree_merge(&target->h, &victim->h, BTREE_TYPE_GEO, gfp);
+}
+
+#if (BITS_PER_LONG > BTREE_TYPE_BITS)
+static inline void *BTREE_FN(lookup)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key)
+{
+ unsigned long _key = key;
+ return btree_lookup(&head->h, BTREE_TYPE_GEO, &_key);
+}
+
+static inline int BTREE_FN(insert)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key,
+ void *val, gfp_t gfp)
+{
+ unsigned long _key = key;
+ return btree_insert(&head->h, BTREE_TYPE_GEO, &_key, val, gfp);
+}
+
+static inline int BTREE_FN(update)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key,
+ void *val)
+{
+ unsigned long _key = key;
+ return btree_update(&head->h, BTREE_TYPE_GEO, &_key, val);
+}
+
+static inline void *BTREE_FN(remove)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key)
+{
+ unsigned long _key = key;
+ return btree_remove(&head->h, BTREE_TYPE_GEO, &_key);
+}
+
+static inline void *BTREE_FN(last)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key)
+{
+ unsigned long _key;
+ void *val = btree_last(&head->h, BTREE_TYPE_GEO, &_key);
+ if (val)
+ *key = _key;
+ return val;
+}
+
+static inline void *BTREE_FN(get_prev)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key)
+{
+ unsigned long _key = *key;
+ void *val = btree_get_prev(&head->h, BTREE_TYPE_GEO, &_key);
+ if (val)
+ *key = _key;
+ return val;
+}
+#else
+static inline void *BTREE_FN(lookup)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key)
+{
+ return btree_lookup(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key);
+}
+
+static inline int BTREE_FN(insert)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key,
+ void *val, gfp_t gfp)
+{
+ return btree_insert(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key,
+ val, gfp);
+}
+
+static inline int BTREE_FN(update)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key,
+ void *val)
+{
+ return btree_update(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key, val);
+}
+
+static inline void *BTREE_FN(remove)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE key)
+{
+ return btree_remove(&head->h, BTREE_TYPE_GEO, (unsigned long *)&key);
+}
+
+static inline void *BTREE_FN(last)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key)
+{
+ return btree_last(&head->h, BTREE_TYPE_GEO, (unsigned long *)key);
+}
+
+static inline void *BTREE_FN(get_prev)(BTREE_TYPE_HEAD *head, BTREE_KEYTYPE *key)
+{
+ return btree_get_prev(&head->h, BTREE_TYPE_GEO, (unsigned long *)key);
+}
+#endif
+
+void VISITOR_FN(void *elem, unsigned long opaque, unsigned long *key,
+ size_t index, void *__func);
+
+typedef void (*VISITOR_FN_T)(void *elem, unsigned long opaque,
+ BTREE_KEYTYPE key, size_t index);
+
+static inline size_t BTREE_FN(visitor)(BTREE_TYPE_HEAD *head,
+ unsigned long opaque,
+ VISITOR_FN_T func2)
+{
+ return btree_visitor(&head->h, BTREE_TYPE_GEO, opaque,
+ visitorl, func2);
+}
+
+static inline size_t BTREE_FN(grim_visitor)(BTREE_TYPE_HEAD *head,
+ unsigned long opaque,
+ VISITOR_FN_T func2)
+{
+ return btree_grim_visitor(&head->h, BTREE_TYPE_GEO, opaque,
+ visitorl, func2);
+}
+
+#undef VISITOR_FN
+#undef VISITOR_FN_T
+#undef __BTREE_TP
+#undef _BTREE_TP
+#undef BTREE_TP
+#undef BTREE_FN
+#undef BTREE_TYPE_HEAD
+#undef BTREE_TYPE_SUFFIX
+#undef BTREE_TYPE_GEO
+#undef BTREE_KEYTYPE
+#undef BTREE_TYPE_BITS
--- wireless-testing.orig/MAINTAINERS 2009-01-10 11:27:45.000000000 +0100
+++ wireless-testing/MAINTAINERS 2009-01-10 11:43:26.000000000 +0100
@@ -866,6 +866,14 @@ L: linux-hams@vger.kernel.org
W: http://www.linux-ax25.org/
S: Maintained

+B+TREE
+P: Johannes Berg
+M: johannes@sipsolutions.net
+P: Joern Engel
+M: joern@logfs.org
+L: linux-kernel@vger.kernel.org
+S: Maintained
+
B43 WIRELESS DRIVER
P: Michael Buesch
M: mb@bu3sch.de