4 #include <linux/types.h>
7 #define FLEX_ARRAY_PART_SIZE PAGE_SIZE
8 #define FLEX_ARRAY_BASE_SIZE PAGE_SIZE
10 struct flex_array_part
;
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
23 int total_nr_elements
;
24 struct flex_array_part
*parts
[];
27 * This little trick makes sure that
28 * sizeof(flex_array) == PAGE_SIZE
30 char padding
[FLEX_ARRAY_BASE_SIZE
];
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))
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 *))
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)
47 * Defines a statically allocated flex array and ensures its parameters are
50 #define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \
51 struct flex_array __arrayname = { { { \
52 .element_size = (__element_size), \
53 .total_nr_elements = (__total), \
55 static inline void __arrayname##_invalid_parameter(void) \
57 BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \
58 FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \
61 struct flex_array
*flex_array_alloc(int element_size
, unsigned int total
,
63 int flex_array_prealloc(struct flex_array
*fa
, unsigned int start
,
64 unsigned int end
, gfp_t flags
);
65 void flex_array_free(struct flex_array
*fa
);
66 void flex_array_free_parts(struct flex_array
*fa
);
67 int flex_array_put(struct flex_array
*fa
, unsigned int element_nr
, void *src
,
69 int flex_array_clear(struct flex_array
*fa
, unsigned int element_nr
);
70 void *flex_array_get(struct flex_array
*fa
, unsigned int element_nr
);
71 int flex_array_shrink(struct flex_array
*fa
);
73 #define flex_array_put_ptr(fa, nr, src, gfp) \
74 flex_array_put(fa, nr, (void *)&(src), gfp)
76 void *flex_array_get_ptr(struct flex_array
*fa
, unsigned int element_nr
);
78 #endif /* _FLEX_ARRAY_H */
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