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131 lines
3.3 KiB
C
131 lines
3.3 KiB
C
#ifndef _LINUX_GENERIC_RADIX_TREE_H
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#define _LINUX_GENERIC_RADIX_TREE_H
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/*
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* Generic radix trees/sparse arrays:
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*
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* A generic radix tree has all nodes of size PAGE_SIZE - both leaves and
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* interior nodes.
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*/
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#include <linux/bug.h>
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#include <linux/kernel.h>
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#include <linux/log2.h>
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struct genradix_node;
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struct __genradix {
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struct genradix_node *root;
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size_t depth;
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};
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/*
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* NOTE: currently, sizeof(_type) must be a power of two and not larger than
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* PAGE_SIZE:
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*/
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#define __GENRADIX_INITIALIZER \
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{ \
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.tree = { \
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.root = NULL, \
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.depth = 0, \
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} \
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}
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/*
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* We use a 0 size array to stash the type we're storing without taking any
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* space at runtime - then the various accessor macros can use typeof() to get
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* to it for casts/sizeof - we also force the alignment so that storing a type
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* with a ridiculous alignment doesn't blow up the alignment or size of the
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* genradix.
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*/
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#define GENRADIX(_type) \
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struct { \
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struct __genradix tree; \
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_type type[0] __aligned(1); \
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}
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#define DEFINE_GENRADIX(_name, _type) \
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GENRADIX(_type) _name = __GENRADIX_INITIALIZER
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#define genradix_init(_radix) \
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do { \
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*(_radix) = (typeof(*_radix)) __GENRADIX_INITIALIZER; \
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} while (0)
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void __genradix_free(struct __genradix *);
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#define genradix_free(_radix) __genradix_free(&(_radix)->tree)
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static inline size_t __idx_to_offset(size_t idx, size_t obj_size)
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{
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BUILD_BUG_ON(obj_size > PAGE_SIZE);
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if (!is_power_of_2(obj_size)) {
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size_t objs_per_page = PAGE_SIZE / obj_size;
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return (idx / objs_per_page) * PAGE_SIZE +
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(idx % objs_per_page) * obj_size;
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} else {
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return idx * obj_size;
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}
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}
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#define __genradix_cast(_radix) (typeof((_radix)->type[0]) *)
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#define __genradix_obj_size(_radix) sizeof((_radix)->type[0])
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#define __genradix_idx_to_offset(_radix, _idx) \
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__idx_to_offset(_idx, __genradix_obj_size(_radix))
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void *__genradix_ptr(struct __genradix *, size_t);
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/* Returns a pointer to element at @_idx */
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#define genradix_ptr(_radix, _idx) \
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(__genradix_cast(_radix) \
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__genradix_ptr(&(_radix)->tree, \
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__genradix_idx_to_offset(_radix, _idx)))
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void *__genradix_ptr_alloc(struct __genradix *, size_t, gfp_t);
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/* Returns a pointer to element at @_idx, allocating it if necessary */
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#define genradix_ptr_alloc(_radix, _idx, _gfp) \
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(__genradix_cast(_radix) \
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__genradix_ptr_alloc(&(_radix)->tree, \
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__genradix_idx_to_offset(_radix, _idx), \
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_gfp))
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struct genradix_iter {
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size_t offset;
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size_t pos;
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};
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#define genradix_iter_init(_radix, _idx) \
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((struct genradix_iter) { \
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.pos = (_idx), \
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.offset = __genradix_idx_to_offset((_radix), (_idx)),\
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})
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void *__genradix_iter_peek(struct genradix_iter *, struct __genradix *, size_t);
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#define genradix_iter_peek(_iter, _radix) \
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(__genradix_cast(_radix) \
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__genradix_iter_peek(_iter, &(_radix)->tree, \
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PAGE_SIZE / __genradix_obj_size(_radix)))
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static inline void __genradix_iter_advance(struct genradix_iter *iter,
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size_t obj_size)
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{
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iter->offset += obj_size;
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if (!is_power_of_2(obj_size) &&
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(iter->offset & (PAGE_SIZE - 1)) + obj_size > PAGE_SIZE)
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iter->offset = round_up(iter->offset, PAGE_SIZE);
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iter->pos++;
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}
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#define genradix_iter_advance(_iter, _radix) \
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__genradix_iter_advance(_iter, __genradix_obj_size(_radix))
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#endif /* _LINUX_GENERIC_RADIX_TREE_H */
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