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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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/** * DOC: Generic radix trees/sparse arrays * * Very simple and minimalistic, supporting arbitrary size entries up to * GENRADIX_NODE_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/slab.h>#include <linux/types.h>
struct genradix_root;
#define GENRADIX_NODE_SHIFT 9#define GENRADIX_NODE_SIZE (1U << GENRADIX_NODE_SHIFT)
#define GENRADIX_ARY (GENRADIX_NODE_SIZE / sizeof(struct genradix_node *))#define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
/* depth that's needed for a genradix that can address up to ULONG_MAX: */#define GENRADIX_MAX_DEPTH \ DIV_ROUND_UP(BITS_PER_LONG - GENRADIX_NODE_SHIFT, GENRADIX_ARY_SHIFT)
#define GENRADIX_DEPTH_MASK \ ((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
static inline int genradix_depth_shift(unsigned depth){ return GENRADIX_NODE_SHIFT + GENRADIX_ARY_SHIFT * depth;}
/* * Returns size (of data, in bytes) that a tree of a given depth holds: */static inline size_t genradix_depth_size(unsigned depth){ return 1UL << genradix_depth_shift(depth);}
static inline unsigned genradix_root_to_depth(struct genradix_root *r){ return (unsigned long) r & GENRADIX_DEPTH_MASK;}
static inline struct genradix_node *genradix_root_to_node(struct genradix_root *r){ return (void *) ((unsigned long) r & ~GENRADIX_DEPTH_MASK);}
struct __genradix { struct genradix_root *root;};
struct genradix_node { union { /* Interior node: */ struct genradix_node *children[GENRADIX_ARY];
/* Leaf: */ u8 data[GENRADIX_NODE_SIZE]; };};
static inline struct genradix_node *genradix_alloc_node(gfp_t gfp_mask){ return kzalloc(GENRADIX_NODE_SIZE, gfp_mask);}
static inline void genradix_free_node(struct genradix_node *node){ kfree(node);}
/* * NOTE: currently, sizeof(_type) must not be larger than GENRADIX_NODE_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 > GENRADIX_NODE_SIZE); else BUG_ON(obj_size > GENRADIX_NODE_SIZE);
if (!is_power_of_2(obj_size)) { size_t objs_per_page = GENRADIX_NODE_SIZE / obj_size;
return (idx / objs_per_page) * GENRADIX_NODE_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) \ (GENRADIX_NODE_SIZE / sizeof((_radix)->type[0]))#define __genradix_page_remainder(_radix) \ (GENRADIX_NODE_SIZE % sizeof((_radix)->type[0]))
#define __genradix_idx_to_offset(_radix, _idx) \ __idx_to_offset(_idx, __genradix_obj_size(_radix))
static inline void *__genradix_ptr_inlined(struct __genradix *radix, size_t offset){ struct genradix_root *r = READ_ONCE(radix->root); struct genradix_node *n = genradix_root_to_node(r); unsigned level = genradix_root_to_depth(r); unsigned shift = genradix_depth_shift(level);
if (unlikely(ilog2(offset) >= genradix_depth_shift(level))) return NULL;
while (n && shift > GENRADIX_NODE_SHIFT) { shift -= GENRADIX_ARY_SHIFT; n = n->children[offset >> shift]; offset &= (1UL << shift) - 1; }
return n ? &n->data[offset] : NULL;}
#define genradix_ptr_inlined(_radix, _idx) \ (__genradix_cast(_radix) \ __genradix_ptr_inlined(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx)))
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, struct genradix_node **, gfp_t);
#define genradix_ptr_alloc_inlined(_radix, _idx, _gfp) \ (__genradix_cast(_radix) \ (__genradix_ptr_inlined(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx)) ?: \ __genradix_ptr_alloc(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx), \ NULL, _gfp)))
#define genradix_ptr_alloc_preallocated_inlined(_radix, _idx, _new_node, _gfp)\ (__genradix_cast(_radix) \ (__genradix_ptr_inlined(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx)) ?: \ __genradix_ptr_alloc(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx), \ _new_node, _gfp)))
/** * 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), \ NULL, _gfp))
#define genradix_ptr_alloc_preallocated(_radix, _idx, _new_node, _gfp)\ (__genradix_cast(_radix) \ __genradix_ptr_alloc(&(_radix)->tree, \ __genradix_idx_to_offset(_radix, _idx), \ _new_node, _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 & (GENRADIX_NODE_SIZE - 1)) + obj_size > GENRADIX_NODE_SIZE) iter->offset = round_up(iter->offset, GENRADIX_NODE_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 & (GENRADIX_NODE_SIZE - 1)) == 0) iter->offset -= GENRADIX_NODE_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 / GENRADIX_NODE_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 */