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/*-
* Copyright (c) 2010 Isilon Systems, Inc.
* Copyright (c) 2010 iX Systems, Inc.
* Copyright (c) 2010 Panasas, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/radix-tree.h>
#include <linux/err.h>
MALLOC_DEFINE(M_RADIX, "radix", "Linux radix compat");
static inline int
radix_max(struct radix_tree_root *root)
{
return (1 << (root->height * RADIX_TREE_MAP_SHIFT)) - 1;
}
static inline int
radix_pos(long id, int height)
{
return (id >> (RADIX_TREE_MAP_SHIFT * height)) & RADIX_TREE_MAP_MASK;
}
void *
radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
{
struct radix_tree_node *node;
void *item;
int height;
item = NULL;
node = root->rnode;
height = root->height - 1;
if (index > radix_max(root))
goto out;
while (height && node)
node = node->slots[radix_pos(index, height--)];
if (node)
item = node->slots[radix_pos(index, 0)];
out:
return (item);
}
void *
radix_tree_delete(struct radix_tree_root *root, unsigned long index)
{
struct radix_tree_node *stack[RADIX_TREE_MAX_HEIGHT];
struct radix_tree_node *node;
void *item;
int height;
int idx;
item = NULL;
node = root->rnode;
height = root->height - 1;
if (index > radix_max(root))
goto out;
/*
* Find the node and record the path in stack.
*/
while (height && node) {
stack[height] = node;
node = node->slots[radix_pos(index, height--)];
}
idx = radix_pos(index, 0);
if (node)
item = node->slots[idx];
/*
* If we removed something reduce the height of the tree.
*/
if (item)
for (;;) {
node->slots[idx] = NULL;
node->count--;
if (node->count > 0)
break;
free(node, M_RADIX);
if (node == root->rnode) {
root->rnode = NULL;
root->height = 0;
break;
}
height++;
node = stack[height];
idx = radix_pos(index, height);
}
out:
return (item);
}
int
radix_tree_insert(struct radix_tree_root *root, unsigned long index, void *item)
{
struct radix_tree_node *node;
int height;
int idx;
/*
* Expand the tree to fit indexes as big as requested.
*/
while (root->rnode == NULL || radix_max(root) < index) {
node = malloc(sizeof(*node), M_RADIX, root->gfp_mask | M_ZERO);
if (node == NULL)
return (-ENOMEM);
node->slots[0] = root->rnode;
if (root->rnode)
node->count++;
root->rnode = node;
root->height++;
}
node = root->rnode;
height = root->height - 1;
/*
* Walk down the tree finding the correct node and allocating any
* missing nodes along the way.
*/
while (height) {
idx = radix_pos(index, height);
if (node->slots[idx] == NULL) {
node->slots[idx] = malloc(sizeof(*node), M_RADIX,
root->gfp_mask | M_ZERO);
if (node->slots[idx] == NULL)
return (-ENOMEM);
node->count++;
}
node = node->slots[idx];
height--;
}
/*
* Insert and adjust count if the item does not already exist.
*/
idx = radix_pos(index, 0);
if (node->slots[idx])
return (-EEXIST);
node->slots[idx] = item;
node->count++;
return (0);
}
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