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534acc05 DH |
1 | #ifndef _FLEX_ARRAY_H |
2 | #define _FLEX_ARRAY_H | |
3 | ||
4 | #include <linux/types.h> | |
5 | #include <asm/page.h> | |
6 | ||
7 | #define FLEX_ARRAY_PART_SIZE PAGE_SIZE | |
8 | #define FLEX_ARRAY_BASE_SIZE PAGE_SIZE | |
9 | ||
10 | struct flex_array_part; | |
11 | ||
12 | /* | |
13 | * This is meant to replace cases where an array-like | |
14 | * structure has gotten too big to fit into kmalloc() | |
15 | * and the developer is getting tempted to use | |
16 | * vmalloc(). | |
17 | */ | |
18 | ||
19 | struct flex_array { | |
20 | union { | |
21 | struct { | |
22 | int element_size; | |
23 | int total_nr_elements; | |
8e7ee270 | 24 | struct flex_array_part *parts[]; |
534acc05 DH |
25 | }; |
26 | /* | |
27 | * This little trick makes sure that | |
28 | * sizeof(flex_array) == PAGE_SIZE | |
29 | */ | |
30 | char padding[FLEX_ARRAY_BASE_SIZE]; | |
31 | }; | |
32 | }; | |
33 | ||
45b588d6 DR |
34 | /* Number of bytes left in base struct flex_array, excluding metadata */ |
35 | #define FLEX_ARRAY_BASE_BYTES_LEFT \ | |
36 | (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) | |
37 | ||
38 | /* Number of pointers in base to struct flex_array_part pages */ | |
39 | #define FLEX_ARRAY_NR_BASE_PTRS \ | |
40 | (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) | |
41 | ||
42 | /* Number of elements of size that fit in struct flex_array_part */ | |
43 | #define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ | |
44 | (FLEX_ARRAY_PART_SIZE / size) | |
45 | ||
46 | /* | |
47 | * Defines a statically allocated flex array and ensures its parameters are | |
48 | * valid. | |
49 | */ | |
50 | #define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \ | |
51 | struct flex_array __arrayname = { { { \ | |
52 | .element_size = (__element_size), \ | |
53 | .total_nr_elements = (__total), \ | |
54 | } } }; \ | |
55 | static inline void __arrayname##_invalid_parameter(void) \ | |
56 | { \ | |
57 | BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \ | |
58 | FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \ | |
59 | } | |
534acc05 | 60 | |
b62e408c DR |
61 | struct flex_array *flex_array_alloc(int element_size, unsigned int total, |
62 | gfp_t flags); | |
63 | int flex_array_prealloc(struct flex_array *fa, unsigned int start, | |
64 | unsigned int end, gfp_t flags); | |
534acc05 DH |
65 | void flex_array_free(struct flex_array *fa); |
66 | void flex_array_free_parts(struct flex_array *fa); | |
b62e408c | 67 | int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, |
534acc05 | 68 | gfp_t flags); |
e6de3988 | 69 | int flex_array_clear(struct flex_array *fa, unsigned int element_nr); |
b62e408c | 70 | void *flex_array_get(struct flex_array *fa, unsigned int element_nr); |
4af5a2f7 | 71 | int flex_array_shrink(struct flex_array *fa); |
534acc05 DH |
72 | |
73 | #endif /* _FLEX_ARRAY_H */ |