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/*
* Copyright (C) 2001 Momchil Velikov
* Portions Copyright (C) 2001 Christoph Hellwig
* Copyright (C) 2006 Nick Piggin
* Copyright (C) 2012 Konstantin Khlebnikov
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef _LINUX_RADIX_TREE_H
#define _LINUX_RADIX_TREE_H
#include <linux/preempt.h>
#include <linux/types.h>
#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/rcupdate.h>
#define RADIX_TREE_INDIRECT_PTR 1
#define RADIX_TREE_EXCEPTIONAL_ENTRY 2
#define RADIX_TREE_EXCEPTIONAL_SHIFT 2
static inline int radix_tree_is_indirect_ptr(void *ptr)
{
return (int)((unsigned long)ptr & RADIX_TREE_INDIRECT_PTR);
}
#define RADIX_TREE_MAX_TAGS 3
struct radix_tree_root {
unsigned int height;
gfp_t gfp_mask;
struct radix_tree_node __rcu *rnode;
};
#define RADIX_TREE_INIT(mask) { \
.height = 0, \
.gfp_mask = (mask), \
.rnode = NULL, \
}
#define RADIX_TREE(name, mask) \
struct radix_tree_root name = RADIX_TREE_INIT(mask)
#define INIT_RADIX_TREE(root, mask) \
do { \
(root)->height = 0; \
(root)->gfp_mask = (mask); \
(root)->rnode = NULL; \
} while (0)
static inline void *radix_tree_deref_slot(void **pslot)
{
return rcu_dereference(*pslot);
}
static inline void *radix_tree_deref_slot_protected(void **pslot,
spinlock_t *treelock)
{
return rcu_dereference_protected(*pslot, lockdep_is_held(treelock));
}
static inline int radix_tree_deref_retry(void *arg)
{
return unlikely((unsigned long)arg & RADIX_TREE_INDIRECT_PTR);
}
static inline int radix_tree_exceptional_entry(void *arg)
{
return (unsigned long)arg & RADIX_TREE_EXCEPTIONAL_ENTRY;
}
static inline int radix_tree_exception(void *arg)
{
return unlikely((unsigned long)arg &
(RADIX_TREE_INDIRECT_PTR | RADIX_TREE_EXCEPTIONAL_ENTRY));
}
static inline void radix_tree_replace_slot(void **pslot, void *item)
{
BUG_ON(radix_tree_is_indirect_ptr(item));
rcu_assign_pointer(*pslot, item);
}
int radix_tree_insert(struct radix_tree_root *, unsigned long, void *);
void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
void *radix_tree_delete(struct radix_tree_root *, unsigned long);
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items);
unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
void ***results, unsigned long *indices,
unsigned long first_index, unsigned int max_items);
unsigned long radix_tree_next_hole(struct radix_tree_root *root,
unsigned long index, unsigned long max_scan);
unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
unsigned long index, unsigned long max_scan);
int radix_tree_preload(gfp_t gfp_mask);
void radix_tree_init(void);
void *radix_tree_tag_set(struct radix_tree_root *root,
unsigned long index, unsigned int tag);
void *radix_tree_tag_clear(struct radix_tree_root *root,
unsigned long index, unsigned int tag);
int radix_tree_tag_get(struct radix_tree_root *root,
unsigned long index, unsigned int tag);
unsigned int
radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items,
unsigned int tag);
unsigned int
radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
unsigned long first_index, unsigned int max_items,
unsigned int tag);
unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
unsigned long *first_indexp, unsigned long last_index,
unsigned long nr_to_tag,
unsigned int fromtag, unsigned int totag);
int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag);
unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item);
static inline void radix_tree_preload_end(void)
{
preempt_enable();
}
struct radix_tree_iter {
unsigned long index;
unsigned long next_index;
unsigned long tags;
};
#define RADIX_TREE_ITER_TAG_MASK 0x00FF
#define RADIX_TREE_ITER_TAGGED 0x0100
#define RADIX_TREE_ITER_CONTIG 0x0200
static __always_inline void **
radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start)
{
iter->index = 0;
iter->next_index = start;
return NULL;
}
void **radix_tree_next_chunk(struct radix_tree_root *root,
struct radix_tree_iter *iter, unsigned flags);
static __always_inline unsigned
radix_tree_chunk_size(struct radix_tree_iter *iter)
{
return iter->next_index - iter->index;
}
static __always_inline void **
radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags)
{
if (flags & RADIX_TREE_ITER_TAGGED) {
iter->tags >>= 1;
if (likely(iter->tags & 1ul)) {
iter->index++;
return slot + 1;
}
if (!(flags & RADIX_TREE_ITER_CONTIG) && likely(iter->tags)) {
unsigned offset = __ffs(iter->tags);
iter->tags >>= offset;
iter->index += offset + 1;
return slot + offset + 1;
}
} else {
unsigned size = radix_tree_chunk_size(iter) - 1;
while (size--) {
slot++;
iter->index++;
if (likely(*slot))
return slot;
if (flags & RADIX_TREE_ITER_CONTIG) {
iter->next_index = 0;
break;
}
}
}
return NULL;
}
#define radix_tree_for_each_chunk(slot, root, iter, start, flags) \
for (slot = radix_tree_iter_init(iter, start) ; \
(slot = radix_tree_next_chunk(root, iter, flags)) ;)
#define radix_tree_for_each_chunk_slot(slot, iter, flags) \
for (; slot ; slot = radix_tree_next_slot(slot, iter, flags))
#define radix_tree_for_each_slot(slot, root, iter, start) \
for (slot = radix_tree_iter_init(iter, start) ; \
slot || (slot = radix_tree_next_chunk(root, iter, 0)) ; \
slot = radix_tree_next_slot(slot, iter, 0))
#define radix_tree_for_each_contig(slot, root, iter, start) \
for (slot = radix_tree_iter_init(iter, start) ; \
slot || (slot = radix_tree_next_chunk(root, iter, \
RADIX_TREE_ITER_CONTIG)) ; \
slot = radix_tree_next_slot(slot, iter, \
RADIX_TREE_ITER_CONTIG))
#define radix_tree_for_each_tagged(slot, root, iter, start, tag) \
for (slot = radix_tree_iter_init(iter, start) ; \
slot || (slot = radix_tree_next_chunk(root, iter, \
RADIX_TREE_ITER_TAGGED | tag)) ; \
slot = radix_tree_next_slot(slot, iter, \
RADIX_TREE_ITER_TAGGED))
#endif
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