2 #include <linux/atomic.h>
3 #include <linux/export.h>
4 #include <linux/generic-radix-tree.h>
6 #include <linux/kmemleak.h>
8 #define GENRADIX_ARY (GENRADIX_NODE_SIZE / sizeof(struct genradix_node *))
9 #define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
11 struct genradix_node
{
14 struct genradix_node
*children
[GENRADIX_ARY
];
17 u8 data
[GENRADIX_NODE_SIZE
];
21 static inline int genradix_depth_shift(unsigned depth
)
23 return GENRADIX_NODE_SHIFT
+ GENRADIX_ARY_SHIFT
* depth
;
27 * Returns size (of data, in bytes) that a tree of a given depth holds:
29 static inline size_t genradix_depth_size(unsigned depth
)
31 return 1UL << genradix_depth_shift(depth
);
34 /* depth that's needed for a genradix that can address up to ULONG_MAX: */
35 #define GENRADIX_MAX_DEPTH \
36 DIV_ROUND_UP(BITS_PER_LONG - GENRADIX_NODE_SHIFT, GENRADIX_ARY_SHIFT)
38 #define GENRADIX_DEPTH_MASK \
39 ((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
41 static inline unsigned genradix_root_to_depth(struct genradix_root
*r
)
43 return (unsigned long) r
& GENRADIX_DEPTH_MASK
;
46 static inline struct genradix_node
*genradix_root_to_node(struct genradix_root
*r
)
48 return (void *) ((unsigned long) r
& ~GENRADIX_DEPTH_MASK
);
52 * Returns pointer to the specified byte @offset within @radix, or NULL if not
55 void *__genradix_ptr(struct __genradix
*radix
, size_t offset
)
57 struct genradix_root
*r
= READ_ONCE(radix
->root
);
58 struct genradix_node
*n
= genradix_root_to_node(r
);
59 unsigned level
= genradix_root_to_depth(r
);
61 if (ilog2(offset
) >= genradix_depth_shift(level
))
72 n
= n
->children
[offset
>> genradix_depth_shift(level
)];
73 offset
&= genradix_depth_size(level
) - 1;
76 return &n
->data
[offset
];
78 EXPORT_SYMBOL(__genradix_ptr
);
80 static inline struct genradix_node
*genradix_alloc_node(gfp_t gfp_mask
)
82 return kzalloc(GENRADIX_NODE_SIZE
, gfp_mask
);
85 static inline void genradix_free_node(struct genradix_node
*node
)
91 * Returns pointer to the specified byte @offset within @radix, allocating it if
92 * necessary - newly allocated slots are always zeroed out:
94 void *__genradix_ptr_alloc(struct __genradix
*radix
, size_t offset
,
97 struct genradix_root
*v
= READ_ONCE(radix
->root
);
98 struct genradix_node
*n
, *new_node
= NULL
;
101 /* Increase tree depth if necessary: */
103 struct genradix_root
*r
= v
, *new_root
;
105 n
= genradix_root_to_node(r
);
106 level
= genradix_root_to_depth(r
);
108 if (n
&& ilog2(offset
) < genradix_depth_shift(level
))
112 new_node
= genradix_alloc_node(gfp_mask
);
117 new_node
->children
[0] = n
;
118 new_root
= ((struct genradix_root
*)
119 ((unsigned long) new_node
| (n
? level
+ 1 : 0)));
121 if ((v
= cmpxchg_release(&radix
->root
, r
, new_root
)) == r
) {
128 struct genradix_node
**p
=
129 &n
->children
[offset
>> genradix_depth_shift(level
)];
130 offset
&= genradix_depth_size(level
) - 1;
135 new_node
= genradix_alloc_node(gfp_mask
);
140 if (!(n
= cmpxchg_release(p
, NULL
, new_node
)))
146 genradix_free_node(new_node
);
148 return &n
->data
[offset
];
150 EXPORT_SYMBOL(__genradix_ptr_alloc
);
152 void *__genradix_iter_peek(struct genradix_iter
*iter
,
153 struct __genradix
*radix
,
154 size_t objs_per_page
)
156 struct genradix_root
*r
;
157 struct genradix_node
*n
;
160 if (iter
->offset
== SIZE_MAX
)
164 r
= READ_ONCE(radix
->root
);
168 n
= genradix_root_to_node(r
);
169 level
= genradix_root_to_depth(r
);
171 if (ilog2(iter
->offset
) >= genradix_depth_shift(level
))
177 i
= (iter
->offset
>> genradix_depth_shift(level
)) &
180 while (!n
->children
[i
]) {
181 size_t objs_per_ptr
= genradix_depth_size(level
);
183 if (iter
->offset
+ objs_per_ptr
< iter
->offset
) {
184 iter
->offset
= SIZE_MAX
;
185 iter
->pos
= SIZE_MAX
;
190 iter
->offset
= round_down(iter
->offset
+ objs_per_ptr
,
192 iter
->pos
= (iter
->offset
>> GENRADIX_NODE_SHIFT
) *
194 if (i
== GENRADIX_ARY
)
201 return &n
->data
[iter
->offset
& (GENRADIX_NODE_SIZE
- 1)];
203 EXPORT_SYMBOL(__genradix_iter_peek
);
205 void *__genradix_iter_peek_prev(struct genradix_iter
*iter
,
206 struct __genradix
*radix
,
207 size_t objs_per_page
,
208 size_t obj_size_plus_page_remainder
)
210 struct genradix_root
*r
;
211 struct genradix_node
*n
;
214 if (iter
->offset
== SIZE_MAX
)
218 r
= READ_ONCE(radix
->root
);
222 n
= genradix_root_to_node(r
);
223 level
= genradix_root_to_depth(r
);
225 if (ilog2(iter
->offset
) >= genradix_depth_shift(level
)) {
226 iter
->offset
= genradix_depth_size(level
);
227 iter
->pos
= (iter
->offset
>> GENRADIX_NODE_SHIFT
) * objs_per_page
;
229 iter
->offset
-= obj_size_plus_page_remainder
;
236 i
= (iter
->offset
>> genradix_depth_shift(level
)) &
239 while (!n
->children
[i
]) {
240 size_t objs_per_ptr
= genradix_depth_size(level
);
242 iter
->offset
= round_down(iter
->offset
, objs_per_ptr
);
243 iter
->pos
= (iter
->offset
>> GENRADIX_NODE_SHIFT
) * objs_per_page
;
248 iter
->offset
-= obj_size_plus_page_remainder
;
259 return &n
->data
[iter
->offset
& (GENRADIX_NODE_SIZE
- 1)];
261 EXPORT_SYMBOL(__genradix_iter_peek_prev
);
263 static void genradix_free_recurse(struct genradix_node
*n
, unsigned level
)
268 for (i
= 0; i
< GENRADIX_ARY
; i
++)
270 genradix_free_recurse(n
->children
[i
], level
- 1);
273 genradix_free_node(n
);
276 int __genradix_prealloc(struct __genradix
*radix
, size_t size
,
281 for (offset
= 0; offset
< size
; offset
+= GENRADIX_NODE_SIZE
)
282 if (!__genradix_ptr_alloc(radix
, offset
, gfp_mask
))
287 EXPORT_SYMBOL(__genradix_prealloc
);
289 void __genradix_free(struct __genradix
*radix
)
291 struct genradix_root
*r
= xchg(&radix
->root
, NULL
);
293 genradix_free_recurse(genradix_root_to_node(r
),
294 genradix_root_to_depth(r
));
296 EXPORT_SYMBOL(__genradix_free
);