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1
2#include <linux/export.h>
3#include <linux/generic-radix-tree.h>
4#include <linux/gfp.h>
5#include <linux/kmemleak.h>
6
7#define GENRADIX_ARY (PAGE_SIZE / sizeof(struct genradix_node *))
8#define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
9
10struct genradix_node {
11 union {
12 /* Interior node: */
13 struct genradix_node *children[GENRADIX_ARY];
14
15 /* Leaf: */
16 u8 data[PAGE_SIZE];
17 };
18};
19
20static inline int genradix_depth_shift(unsigned depth)
21{
22 return PAGE_SHIFT + GENRADIX_ARY_SHIFT * depth;
23}
24
25/*
26 * Returns size (of data, in bytes) that a tree of a given depth holds:
27 */
28static inline size_t genradix_depth_size(unsigned depth)
29{
30 return 1UL << genradix_depth_shift(depth);
31}
32
33/* depth that's needed for a genradix that can address up to ULONG_MAX: */
34#define GENRADIX_MAX_DEPTH \
35 DIV_ROUND_UP(BITS_PER_LONG - PAGE_SHIFT, GENRADIX_ARY_SHIFT)
36
37#define GENRADIX_DEPTH_MASK \
38 ((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
39
40static inline unsigned genradix_root_to_depth(struct genradix_root *r)
41{
42 return (unsigned long) r & GENRADIX_DEPTH_MASK;
43}
44
45static inline struct genradix_node *genradix_root_to_node(struct genradix_root *r)
46{
47 return (void *) ((unsigned long) r & ~GENRADIX_DEPTH_MASK);
48}
49
50/*
51 * Returns pointer to the specified byte @offset within @radix, or NULL if not
52 * allocated
53 */
54void *__genradix_ptr(struct __genradix *radix, size_t offset)
55{
56 struct genradix_root *r = READ_ONCE(radix->root);
57 struct genradix_node *n = genradix_root_to_node(r);
58 unsigned level = genradix_root_to_depth(r);
59
60 if (ilog2(offset) >= genradix_depth_shift(level))
61 return NULL;
62
63 while (1) {
64 if (!n)
65 return NULL;
66 if (!level)
67 break;
68
69 level--;
70
71 n = n->children[offset >> genradix_depth_shift(level)];
72 offset &= genradix_depth_size(level) - 1;
73 }
74
75 return &n->data[offset];
76}
77EXPORT_SYMBOL(__genradix_ptr);
78
79static inline struct genradix_node *genradix_alloc_node(gfp_t gfp_mask)
80{
81 struct genradix_node *node;
82
83 node = (struct genradix_node *)__get_free_page(gfp_mask|__GFP_ZERO);
84
85 /*
86 * We're using pages (not slab allocations) directly for kernel data
87 * structures, so we need to explicitly inform kmemleak of them in order
88 * to avoid false positive memory leak reports.
89 */
90 kmemleak_alloc(node, PAGE_SIZE, 1, gfp_mask);
91 return node;
92}
93
94static inline void genradix_free_node(struct genradix_node *node)
95{
96 kmemleak_free(node);
97 free_page((unsigned long)node);
98}
99
100/*
101 * Returns pointer to the specified byte @offset within @radix, allocating it if
102 * necessary - newly allocated slots are always zeroed out:
103 */
104void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
105 gfp_t gfp_mask)
106{
107 struct genradix_root *v = READ_ONCE(radix->root);
108 struct genradix_node *n, *new_node = NULL;
109 unsigned level;
110
111 /* Increase tree depth if necessary: */
112 while (1) {
113 struct genradix_root *r = v, *new_root;
114
115 n = genradix_root_to_node(r);
116 level = genradix_root_to_depth(r);
117
118 if (n && ilog2(offset) < genradix_depth_shift(level))
119 break;
120
121 if (!new_node) {
122 new_node = genradix_alloc_node(gfp_mask);
123 if (!new_node)
124 return NULL;
125 }
126
127 new_node->children[0] = n;
128 new_root = ((struct genradix_root *)
129 ((unsigned long) new_node | (n ? level + 1 : 0)));
130
131 if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
132 v = new_root;
133 new_node = NULL;
134 }
135 }
136
137 while (level--) {
138 struct genradix_node **p =
139 &n->children[offset >> genradix_depth_shift(level)];
140 offset &= genradix_depth_size(level) - 1;
141
142 n = READ_ONCE(*p);
143 if (!n) {
144 if (!new_node) {
145 new_node = genradix_alloc_node(gfp_mask);
146 if (!new_node)
147 return NULL;
148 }
149
150 if (!(n = cmpxchg_release(p, NULL, new_node)))
151 swap(n, new_node);
152 }
153 }
154
155 if (new_node)
156 genradix_free_node(new_node);
157
158 return &n->data[offset];
159}
160EXPORT_SYMBOL(__genradix_ptr_alloc);
161
162void *__genradix_iter_peek(struct genradix_iter *iter,
163 struct __genradix *radix,
164 size_t objs_per_page)
165{
166 struct genradix_root *r;
167 struct genradix_node *n;
168 unsigned level, i;
169restart:
170 r = READ_ONCE(radix->root);
171 if (!r)
172 return NULL;
173
174 n = genradix_root_to_node(r);
175 level = genradix_root_to_depth(r);
176
177 if (ilog2(iter->offset) >= genradix_depth_shift(level))
178 return NULL;
179
180 while (level) {
181 level--;
182
183 i = (iter->offset >> genradix_depth_shift(level)) &
184 (GENRADIX_ARY - 1);
185
186 while (!n->children[i]) {
187 i++;
188 iter->offset = round_down(iter->offset +
189 genradix_depth_size(level),
190 genradix_depth_size(level));
191 iter->pos = (iter->offset >> PAGE_SHIFT) *
192 objs_per_page;
193 if (i == GENRADIX_ARY)
194 goto restart;
195 }
196
197 n = n->children[i];
198 }
199
200 return &n->data[iter->offset & (PAGE_SIZE - 1)];
201}
202EXPORT_SYMBOL(__genradix_iter_peek);
203
204static void genradix_free_recurse(struct genradix_node *n, unsigned level)
205{
206 if (level) {
207 unsigned i;
208
209 for (i = 0; i < GENRADIX_ARY; i++)
210 if (n->children[i])
211 genradix_free_recurse(n->children[i], level - 1);
212 }
213
214 genradix_free_node(n);
215}
216
217int __genradix_prealloc(struct __genradix *radix, size_t size,
218 gfp_t gfp_mask)
219{
220 size_t offset;
221
222 for (offset = 0; offset < size; offset += PAGE_SIZE)
223 if (!__genradix_ptr_alloc(radix, offset, gfp_mask))
224 return -ENOMEM;
225
226 return 0;
227}
228EXPORT_SYMBOL(__genradix_prealloc);
229
230void __genradix_free(struct __genradix *radix)
231{
232 struct genradix_root *r = xchg(&radix->root, NULL);
233
234 genradix_free_recurse(genradix_root_to_node(r),
235 genradix_root_to_depth(r));
236}
237EXPORT_SYMBOL(__genradix_free);
1
2#include <linux/atomic.h>
3#include <linux/export.h>
4#include <linux/generic-radix-tree.h>
5#include <linux/gfp.h>
6#include <linux/kmemleak.h>
7
8/*
9 * Returns pointer to the specified byte @offset within @radix, or NULL if not
10 * allocated
11 */
12void *__genradix_ptr(struct __genradix *radix, size_t offset)
13{
14 return __genradix_ptr_inlined(radix, offset);
15}
16EXPORT_SYMBOL(__genradix_ptr);
17
18/*
19 * Returns pointer to the specified byte @offset within @radix, allocating it if
20 * necessary - newly allocated slots are always zeroed out:
21 */
22void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
23 struct genradix_node **preallocated,
24 gfp_t gfp_mask)
25{
26 struct genradix_root *v = READ_ONCE(radix->root);
27 struct genradix_node *n, *new_node = NULL;
28 unsigned level;
29
30 if (preallocated)
31 swap(new_node, *preallocated);
32
33 /* Increase tree depth if necessary: */
34 while (1) {
35 struct genradix_root *r = v, *new_root;
36
37 n = genradix_root_to_node(r);
38 level = genradix_root_to_depth(r);
39
40 if (n && ilog2(offset) < genradix_depth_shift(level))
41 break;
42
43 if (!new_node) {
44 new_node = genradix_alloc_node(gfp_mask);
45 if (!new_node)
46 return NULL;
47 }
48
49 new_node->children[0] = n;
50 new_root = ((struct genradix_root *)
51 ((unsigned long) new_node | (n ? level + 1 : 0)));
52
53 if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
54 v = new_root;
55 new_node = NULL;
56 } else {
57 new_node->children[0] = NULL;
58 }
59 }
60
61 while (level--) {
62 struct genradix_node **p =
63 &n->children[offset >> genradix_depth_shift(level)];
64 offset &= genradix_depth_size(level) - 1;
65
66 n = READ_ONCE(*p);
67 if (!n) {
68 if (!new_node) {
69 new_node = genradix_alloc_node(gfp_mask);
70 if (!new_node)
71 return NULL;
72 }
73
74 if (!(n = cmpxchg_release(p, NULL, new_node)))
75 swap(n, new_node);
76 }
77 }
78
79 if (new_node)
80 genradix_free_node(new_node);
81
82 return &n->data[offset];
83}
84EXPORT_SYMBOL(__genradix_ptr_alloc);
85
86void *__genradix_iter_peek(struct genradix_iter *iter,
87 struct __genradix *radix,
88 size_t objs_per_page)
89{
90 struct genradix_root *r;
91 struct genradix_node *n;
92 unsigned level, i;
93
94 if (iter->offset == SIZE_MAX)
95 return NULL;
96
97restart:
98 r = READ_ONCE(radix->root);
99 if (!r)
100 return NULL;
101
102 n = genradix_root_to_node(r);
103 level = genradix_root_to_depth(r);
104
105 if (ilog2(iter->offset) >= genradix_depth_shift(level))
106 return NULL;
107
108 while (level) {
109 level--;
110
111 i = (iter->offset >> genradix_depth_shift(level)) &
112 (GENRADIX_ARY - 1);
113
114 while (!n->children[i]) {
115 size_t objs_per_ptr = genradix_depth_size(level);
116
117 if (iter->offset + objs_per_ptr < iter->offset) {
118 iter->offset = SIZE_MAX;
119 iter->pos = SIZE_MAX;
120 return NULL;
121 }
122
123 i++;
124 iter->offset = round_down(iter->offset + objs_per_ptr,
125 objs_per_ptr);
126 iter->pos = (iter->offset >> GENRADIX_NODE_SHIFT) *
127 objs_per_page;
128 if (i == GENRADIX_ARY)
129 goto restart;
130 }
131
132 n = n->children[i];
133 }
134
135 return &n->data[iter->offset & (GENRADIX_NODE_SIZE - 1)];
136}
137EXPORT_SYMBOL(__genradix_iter_peek);
138
139void *__genradix_iter_peek_prev(struct genradix_iter *iter,
140 struct __genradix *radix,
141 size_t objs_per_page,
142 size_t obj_size_plus_page_remainder)
143{
144 struct genradix_root *r;
145 struct genradix_node *n;
146 unsigned level, i;
147
148 if (iter->offset == SIZE_MAX)
149 return NULL;
150
151restart:
152 r = READ_ONCE(radix->root);
153 if (!r)
154 return NULL;
155
156 n = genradix_root_to_node(r);
157 level = genradix_root_to_depth(r);
158
159 if (ilog2(iter->offset) >= genradix_depth_shift(level)) {
160 iter->offset = genradix_depth_size(level);
161 iter->pos = (iter->offset >> GENRADIX_NODE_SHIFT) * objs_per_page;
162
163 iter->offset -= obj_size_plus_page_remainder;
164 iter->pos--;
165 }
166
167 while (level) {
168 level--;
169
170 i = (iter->offset >> genradix_depth_shift(level)) &
171 (GENRADIX_ARY - 1);
172
173 while (!n->children[i]) {
174 size_t objs_per_ptr = genradix_depth_size(level);
175
176 iter->offset = round_down(iter->offset, objs_per_ptr);
177 iter->pos = (iter->offset >> GENRADIX_NODE_SHIFT) * objs_per_page;
178
179 if (!iter->offset)
180 return NULL;
181
182 iter->offset -= obj_size_plus_page_remainder;
183 iter->pos--;
184
185 if (!i)
186 goto restart;
187 --i;
188 }
189
190 n = n->children[i];
191 }
192
193 return &n->data[iter->offset & (GENRADIX_NODE_SIZE - 1)];
194}
195EXPORT_SYMBOL(__genradix_iter_peek_prev);
196
197static void genradix_free_recurse(struct genradix_node *n, unsigned level)
198{
199 if (level) {
200 unsigned i;
201
202 for (i = 0; i < GENRADIX_ARY; i++)
203 if (n->children[i])
204 genradix_free_recurse(n->children[i], level - 1);
205 }
206
207 genradix_free_node(n);
208}
209
210int __genradix_prealloc(struct __genradix *radix, size_t size,
211 gfp_t gfp_mask)
212{
213 size_t offset;
214
215 for (offset = 0; offset < size; offset += GENRADIX_NODE_SIZE)
216 if (!__genradix_ptr_alloc(radix, offset, NULL, gfp_mask))
217 return -ENOMEM;
218
219 return 0;
220}
221EXPORT_SYMBOL(__genradix_prealloc);
222
223void __genradix_free(struct __genradix *radix)
224{
225 struct genradix_root *r = xchg(&radix->root, NULL);
226
227 genradix_free_recurse(genradix_root_to_node(r),
228 genradix_root_to_depth(r));
229}
230EXPORT_SYMBOL(__genradix_free);