+++ /dev/null
-#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/limits.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_objs_per_page(_radix) \
- (PAGE_SIZE / sizeof((_radix)->type[0]))
-#define __genradix_page_remainder(_radix) \
- (PAGE_SIZE % 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, \
- __genradix_objs_per_page(_radix)))
-
-void *__genradix_iter_peek_prev(struct genradix_iter *, struct __genradix *,
- size_t, size_t);
-
-/**
- * genradix_iter_peek_prev - get first entry at or below iterator's current
- * position
- * @_iter: a genradix_iter
- * @_radix: genradix being iterated over
- *
- * If no more entries exist at or below @_iter's current position, returns NULL
- */
-#define genradix_iter_peek_prev(_iter, _radix) \
- (__genradix_cast(_radix) \
- __genradix_iter_peek_prev(_iter, &(_radix)->tree, \
- __genradix_objs_per_page(_radix), \
- __genradix_obj_size(_radix) + \
- __genradix_page_remainder(_radix)))
-
-static inline void __genradix_iter_advance(struct genradix_iter *iter,
- size_t obj_size)
-{
- if (iter->offset + obj_size < iter->offset) {
- iter->offset = SIZE_MAX;
- iter->pos = SIZE_MAX;
- return;
- }
-
- 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))
-
-static inline void __genradix_iter_rewind(struct genradix_iter *iter,
- size_t obj_size)
-{
- if (iter->offset == 0 ||
- iter->offset == SIZE_MAX) {
- iter->offset = SIZE_MAX;
- return;
- }
-
- if ((iter->offset & (PAGE_SIZE - 1)) == 0)
- iter->offset -= PAGE_SIZE % obj_size;
-
- iter->offset -= obj_size;
- iter->pos--;
-}
-
-#define genradix_iter_rewind(_iter, _radix) \
- __genradix_iter_rewind(_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)
-
-#define genradix_last_pos(_radix) \
- (SIZE_MAX / PAGE_SIZE * __genradix_objs_per_page(_radix) - 1)
-
-/**
- * genradix_for_each_reverse - iterate over entry in a genradix, reverse order
- * @_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_reverse(_radix, _iter, _p) \
- for (_iter = genradix_iter_init(_radix, genradix_last_pos(_radix));\
- (_p = genradix_iter_peek_prev(&_iter, _radix)) != NULL;\
- genradix_iter_rewind(&_iter, _radix))
-
-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 */
projects / bcachefs-tools-debian / blobdiff