233 lines
6.4 KiB
C
233 lines
6.4 KiB
C
#ifndef _LINUX_GENERIC_RADIX_TREE_H
|
|
#define _LINUX_GENERIC_RADIX_TREE_H
|
|
|
|
/**
|
|
* DOC: Generic radix trees/sparse arrays
|
|
*
|
|
* Very simple and minimalistic, supporting arbitrary size entries up to
|
|
* PAGE_SIZE.
|
|
*
|
|
* A genradix is defined with the type it will store, like so:
|
|
*
|
|
* static GENRADIX(struct foo) foo_genradix;
|
|
*
|
|
* The main operations are:
|
|
*
|
|
* - genradix_init(radix) - initialize an empty genradix
|
|
*
|
|
* - genradix_free(radix) - free all memory owned by the genradix and
|
|
* reinitialize it
|
|
*
|
|
* - genradix_ptr(radix, idx) - gets a pointer to the entry at idx, returning
|
|
* NULL if that entry does not exist
|
|
*
|
|
* - genradix_ptr_alloc(radix, idx, gfp) - gets a pointer to an entry,
|
|
* allocating it if necessary
|
|
*
|
|
* - genradix_for_each(radix, iter, p) - iterate over each entry in a genradix
|
|
*
|
|
* The radix tree allocates one page of entries at a time, so entries may exist
|
|
* that were never explicitly allocated - they will be initialized to all
|
|
* zeroes.
|
|
*
|
|
* Internally, a genradix is just a radix tree of pages, and indexing works in
|
|
* terms of byte offsets. The wrappers in this header file use sizeof on the
|
|
* type the radix contains to calculate a byte offset from the index - see
|
|
* __idx_to_offset.
|
|
*/
|
|
|
|
#include <asm/page.h>
|
|
#include <linux/bug.h>
|
|
#include <linux/log2.h>
|
|
#include <linux/math.h>
|
|
#include <linux/types.h>
|
|
|
|
struct genradix_root;
|
|
|
|
struct __genradix {
|
|
struct genradix_root *root;
|
|
};
|
|
|
|
/*
|
|
* NOTE: currently, sizeof(_type) must not be larger than PAGE_SIZE:
|
|
*/
|
|
|
|
#define __GENRADIX_INITIALIZER \
|
|
{ \
|
|
.tree = { \
|
|
.root = NULL, \
|
|
} \
|
|
}
|
|
|
|
/*
|
|
* We use a 0 size array to stash the type we're storing without taking any
|
|
* space at runtime - then the various accessor macros can use typeof() to get
|
|
* to it for casts/sizeof - we also force the alignment so that storing a type
|
|
* with a ridiculous alignment doesn't blow up the alignment or size of the
|
|
* genradix.
|
|
*/
|
|
|
|
#define GENRADIX(_type) \
|
|
struct { \
|
|
struct __genradix tree; \
|
|
_type type[0] __aligned(1); \
|
|
}
|
|
|
|
#define DEFINE_GENRADIX(_name, _type) \
|
|
GENRADIX(_type) _name = __GENRADIX_INITIALIZER
|
|
|
|
/**
|
|
* genradix_init - initialize a genradix
|
|
* @_radix: genradix to initialize
|
|
*
|
|
* Does not fail
|
|
*/
|
|
#define genradix_init(_radix) \
|
|
do { \
|
|
*(_radix) = (typeof(*_radix)) __GENRADIX_INITIALIZER; \
|
|
} while (0)
|
|
|
|
void __genradix_free(struct __genradix *);
|
|
|
|
/**
|
|
* genradix_free: free all memory owned by a genradix
|
|
* @_radix: the genradix to free
|
|
*
|
|
* After freeing, @_radix will be reinitialized and empty
|
|
*/
|
|
#define genradix_free(_radix) __genradix_free(&(_radix)->tree)
|
|
|
|
static inline size_t __idx_to_offset(size_t idx, size_t obj_size)
|
|
{
|
|
if (__builtin_constant_p(obj_size))
|
|
BUILD_BUG_ON(obj_size > PAGE_SIZE);
|
|
else
|
|
BUG_ON(obj_size > PAGE_SIZE);
|
|
|
|
if (!is_power_of_2(obj_size)) {
|
|
size_t objs_per_page = PAGE_SIZE / obj_size;
|
|
|
|
return (idx / objs_per_page) * PAGE_SIZE +
|
|
(idx % objs_per_page) * obj_size;
|
|
} else {
|
|
return idx * obj_size;
|
|
}
|
|
}
|
|
|
|
#define __genradix_cast(_radix) (typeof((_radix)->type[0]) *)
|
|
#define __genradix_obj_size(_radix) sizeof((_radix)->type[0])
|
|
#define __genradix_idx_to_offset(_radix, _idx) \
|
|
__idx_to_offset(_idx, __genradix_obj_size(_radix))
|
|
|
|
void *__genradix_ptr(struct __genradix *, size_t);
|
|
|
|
/**
|
|
* genradix_ptr - get a pointer to a genradix entry
|
|
* @_radix: genradix to access
|
|
* @_idx: index to fetch
|
|
*
|
|
* Returns a pointer to entry at @_idx, or NULL if that entry does not exist.
|
|
*/
|
|
#define genradix_ptr(_radix, _idx) \
|
|
(__genradix_cast(_radix) \
|
|
__genradix_ptr(&(_radix)->tree, \
|
|
__genradix_idx_to_offset(_radix, _idx)))
|
|
|
|
void *__genradix_ptr_alloc(struct __genradix *, size_t, gfp_t);
|
|
|
|
/**
|
|
* genradix_ptr_alloc - get a pointer to a genradix entry, allocating it
|
|
* if necessary
|
|
* @_radix: genradix to access
|
|
* @_idx: index to fetch
|
|
* @_gfp: gfp mask
|
|
*
|
|
* Returns a pointer to entry at @_idx, or NULL on allocation failure
|
|
*/
|
|
#define genradix_ptr_alloc(_radix, _idx, _gfp) \
|
|
(__genradix_cast(_radix) \
|
|
__genradix_ptr_alloc(&(_radix)->tree, \
|
|
__genradix_idx_to_offset(_radix, _idx), \
|
|
_gfp))
|
|
|
|
struct genradix_iter {
|
|
size_t offset;
|
|
size_t pos;
|
|
};
|
|
|
|
/**
|
|
* genradix_iter_init - initialize a genradix_iter
|
|
* @_radix: genradix that will be iterated over
|
|
* @_idx: index to start iterating from
|
|
*/
|
|
#define genradix_iter_init(_radix, _idx) \
|
|
((struct genradix_iter) { \
|
|
.pos = (_idx), \
|
|
.offset = __genradix_idx_to_offset((_radix), (_idx)),\
|
|
})
|
|
|
|
void *__genradix_iter_peek(struct genradix_iter *, struct __genradix *, size_t);
|
|
|
|
/**
|
|
* genradix_iter_peek - get first entry at or above iterator's current
|
|
* position
|
|
* @_iter: a genradix_iter
|
|
* @_radix: genradix being iterated over
|
|
*
|
|
* If no more entries exist at or above @_iter's current position, returns NULL
|
|
*/
|
|
#define genradix_iter_peek(_iter, _radix) \
|
|
(__genradix_cast(_radix) \
|
|
__genradix_iter_peek(_iter, &(_radix)->tree, \
|
|
PAGE_SIZE / __genradix_obj_size(_radix)))
|
|
|
|
static inline void __genradix_iter_advance(struct genradix_iter *iter,
|
|
size_t obj_size)
|
|
{
|
|
iter->offset += obj_size;
|
|
|
|
if (!is_power_of_2(obj_size) &&
|
|
(iter->offset & (PAGE_SIZE - 1)) + obj_size > PAGE_SIZE)
|
|
iter->offset = round_up(iter->offset, PAGE_SIZE);
|
|
|
|
iter->pos++;
|
|
}
|
|
|
|
#define genradix_iter_advance(_iter, _radix) \
|
|
__genradix_iter_advance(_iter, __genradix_obj_size(_radix))
|
|
|
|
#define genradix_for_each_from(_radix, _iter, _p, _start) \
|
|
for (_iter = genradix_iter_init(_radix, _start); \
|
|
(_p = genradix_iter_peek(&_iter, _radix)) != NULL; \
|
|
genradix_iter_advance(&_iter, _radix))
|
|
|
|
/**
|
|
* genradix_for_each - iterate over entry in a genradix
|
|
* @_radix: genradix to iterate over
|
|
* @_iter: a genradix_iter to track current position
|
|
* @_p: pointer to genradix entry type
|
|
*
|
|
* On every iteration, @_p will point to the current entry, and @_iter.pos
|
|
* will be the current entry's index.
|
|
*/
|
|
#define genradix_for_each(_radix, _iter, _p) \
|
|
genradix_for_each_from(_radix, _iter, _p, 0)
|
|
|
|
int __genradix_prealloc(struct __genradix *, size_t, gfp_t);
|
|
|
|
/**
|
|
* genradix_prealloc - preallocate entries in a generic radix tree
|
|
* @_radix: genradix to preallocate
|
|
* @_nr: number of entries to preallocate
|
|
* @_gfp: gfp mask
|
|
*
|
|
* Returns 0 on success, -ENOMEM on failure
|
|
*/
|
|
#define genradix_prealloc(_radix, _nr, _gfp) \
|
|
__genradix_prealloc(&(_radix)->tree, \
|
|
__genradix_idx_to_offset(_radix, _nr + 1),\
|
|
_gfp)
|
|
|
|
|
|
#endif /* _LINUX_GENERIC_RADIX_TREE_H */
|