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