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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
534acc05 DH |
2 | #ifndef _FLEX_ARRAY_H |
3 | #define _FLEX_ARRAY_H | |
4 | ||
5 | #include <linux/types.h> | |
809fa972 | 6 | #include <linux/reciprocal_div.h> |
534acc05 DH |
7 | #include <asm/page.h> |
8 | ||
9 | #define FLEX_ARRAY_PART_SIZE PAGE_SIZE | |
10 | #define FLEX_ARRAY_BASE_SIZE PAGE_SIZE | |
11 | ||
12 | struct flex_array_part; | |
13 | ||
14 | /* | |
15 | * This is meant to replace cases where an array-like | |
16 | * structure has gotten too big to fit into kmalloc() | |
17 | * and the developer is getting tempted to use | |
18 | * vmalloc(). | |
19 | */ | |
20 | ||
21 | struct flex_array { | |
22 | union { | |
23 | struct { | |
24 | int element_size; | |
25 | int total_nr_elements; | |
704f15dd | 26 | int elems_per_part; |
809fa972 | 27 | struct reciprocal_value reciprocal_elems; |
8e7ee270 | 28 | struct flex_array_part *parts[]; |
534acc05 DH |
29 | }; |
30 | /* | |
31 | * This little trick makes sure that | |
32 | * sizeof(flex_array) == PAGE_SIZE | |
33 | */ | |
34 | char padding[FLEX_ARRAY_BASE_SIZE]; | |
35 | }; | |
36 | }; | |
37 | ||
45b588d6 DR |
38 | /* Number of bytes left in base struct flex_array, excluding metadata */ |
39 | #define FLEX_ARRAY_BASE_BYTES_LEFT \ | |
40 | (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) | |
41 | ||
42 | /* Number of pointers in base to struct flex_array_part pages */ | |
43 | #define FLEX_ARRAY_NR_BASE_PTRS \ | |
44 | (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) | |
45 | ||
46 | /* Number of elements of size that fit in struct flex_array_part */ | |
47 | #define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ | |
48 | (FLEX_ARRAY_PART_SIZE / size) | |
49 | ||
50 | /* | |
51 | * Defines a statically allocated flex array and ensures its parameters are | |
52 | * valid. | |
53 | */ | |
54 | #define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \ | |
55 | struct flex_array __arrayname = { { { \ | |
56 | .element_size = (__element_size), \ | |
57 | .total_nr_elements = (__total), \ | |
58 | } } }; \ | |
59 | static inline void __arrayname##_invalid_parameter(void) \ | |
60 | { \ | |
61 | BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \ | |
62 | FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \ | |
63 | } | |
534acc05 | 64 | |
b2e33536 | 65 | /** |
66 | * flex_array_alloc() - Creates a flexible array. | |
67 | * @element_size: individual object size. | |
68 | * @total: maximum number of objects which can be stored. | |
69 | * @flags: GFP flags | |
70 | * | |
71 | * Return: Returns an object of structure flex_array. | |
72 | */ | |
b62e408c DR |
73 | struct flex_array *flex_array_alloc(int element_size, unsigned int total, |
74 | gfp_t flags); | |
b2e33536 | 75 | |
76 | /** | |
77 | * flex_array_prealloc() - Ensures that memory for the elements indexed in the | |
78 | * range defined by start and nr_elements has been allocated. | |
79 | * @fa: array to allocate memory to. | |
80 | * @start: start address | |
81 | * @nr_elements: number of elements to be allocated. | |
82 | * @flags: GFP flags | |
83 | * | |
84 | */ | |
b62e408c | 85 | int flex_array_prealloc(struct flex_array *fa, unsigned int start, |
5d30b10b | 86 | unsigned int nr_elements, gfp_t flags); |
b2e33536 | 87 | |
88 | /** | |
89 | * flex_array_free() - Removes all elements of a flexible array. | |
90 | * @fa: array to be freed. | |
91 | */ | |
534acc05 | 92 | void flex_array_free(struct flex_array *fa); |
b2e33536 | 93 | |
94 | /** | |
95 | * flex_array_free_parts() - Removes all elements of a flexible array, but | |
96 | * leaves the array itself in place. | |
97 | * @fa: array to be emptied. | |
98 | */ | |
534acc05 | 99 | void flex_array_free_parts(struct flex_array *fa); |
b2e33536 | 100 | |
101 | /** | |
102 | * flex_array_put() - Stores data into a flexible array. | |
103 | * @fa: array where element is to be stored. | |
104 | * @element_nr: position to copy, must be less than the maximum specified when | |
105 | * the array was created. | |
106 | * @src: data source to be copied into the array. | |
107 | * @flags: GFP flags | |
108 | * | |
109 | * Return: Returns zero on success, a negative error code otherwise. | |
110 | */ | |
b62e408c | 111 | int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, |
534acc05 | 112 | gfp_t flags); |
b2e33536 | 113 | |
114 | /** | |
115 | * flex_array_clear() - Clears an individual element in the array, sets the | |
116 | * given element to FLEX_ARRAY_FREE. | |
117 | * @element_nr: element position to clear. | |
118 | * @fa: array to which element to be cleared belongs. | |
119 | * | |
120 | * Return: Returns zero on success, -EINVAL otherwise. | |
121 | */ | |
e6de3988 | 122 | int flex_array_clear(struct flex_array *fa, unsigned int element_nr); |
b2e33536 | 123 | |
124 | /** | |
125 | * flex_array_get() - Retrieves data into a flexible array. | |
126 | * | |
127 | * @element_nr: Element position to retrieve data from. | |
128 | * @fa: array from which data is to be retrieved. | |
129 | * | |
130 | * Return: Returns a pointer to the data element, or NULL if that | |
131 | * particular element has never been allocated. | |
132 | */ | |
b62e408c | 133 | void *flex_array_get(struct flex_array *fa, unsigned int element_nr); |
b2e33536 | 134 | |
135 | /** | |
136 | * flex_array_shrink() - Reduces the allocated size of an array. | |
137 | * @fa: array to shrink. | |
138 | * | |
139 | * Return: Returns number of pages of memory actually freed. | |
140 | * | |
141 | */ | |
4af5a2f7 | 142 | int flex_array_shrink(struct flex_array *fa); |
534acc05 | 143 | |
ea98eed9 | 144 | #define flex_array_put_ptr(fa, nr, src, gfp) \ |
c41ab6a1 | 145 | flex_array_put(fa, nr, (void *)&(src), gfp) |
ea98eed9 EP |
146 | |
147 | void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr); | |
148 | ||
534acc05 | 149 | #endif /* _FLEX_ARRAY_H */ |