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81 lines
2.4 KiB
81 lines
2.4 KiB
#ifndef _FLEX_ARRAY_H |
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#define _FLEX_ARRAY_H |
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#include <linux/types.h> |
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#include <linux/reciprocal_div.h> |
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#include <asm/page.h> |
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#define FLEX_ARRAY_PART_SIZE PAGE_SIZE |
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#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE |
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struct flex_array_part; |
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/* |
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* This is meant to replace cases where an array-like |
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* structure has gotten too big to fit into kmalloc() |
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* and the developer is getting tempted to use |
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* vmalloc(). |
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*/ |
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struct flex_array { |
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union { |
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struct { |
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int element_size; |
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int total_nr_elements; |
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int elems_per_part; |
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struct reciprocal_value reciprocal_elems; |
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struct flex_array_part *parts[]; |
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}; |
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/* |
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* This little trick makes sure that |
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* sizeof(flex_array) == PAGE_SIZE |
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*/ |
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char padding[FLEX_ARRAY_BASE_SIZE]; |
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}; |
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}; |
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/* Number of bytes left in base struct flex_array, excluding metadata */ |
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#define FLEX_ARRAY_BASE_BYTES_LEFT \ |
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(FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) |
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/* Number of pointers in base to struct flex_array_part pages */ |
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#define FLEX_ARRAY_NR_BASE_PTRS \ |
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(FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) |
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/* Number of elements of size that fit in struct flex_array_part */ |
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#define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ |
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(FLEX_ARRAY_PART_SIZE / size) |
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/* |
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* Defines a statically allocated flex array and ensures its parameters are |
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* valid. |
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*/ |
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#define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \ |
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struct flex_array __arrayname = { { { \ |
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.element_size = (__element_size), \ |
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.total_nr_elements = (__total), \ |
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} } }; \ |
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static inline void __arrayname##_invalid_parameter(void) \ |
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{ \ |
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BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \ |
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FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \ |
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} |
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struct flex_array *flex_array_alloc(int element_size, unsigned int total, |
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gfp_t flags); |
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int flex_array_prealloc(struct flex_array *fa, unsigned int start, |
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unsigned int nr_elements, gfp_t flags); |
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void flex_array_free(struct flex_array *fa); |
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void flex_array_free_parts(struct flex_array *fa); |
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int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, |
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gfp_t flags); |
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int flex_array_clear(struct flex_array *fa, unsigned int element_nr); |
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void *flex_array_get(struct flex_array *fa, unsigned int element_nr); |
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int flex_array_shrink(struct flex_array *fa); |
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#define flex_array_put_ptr(fa, nr, src, gfp) \ |
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flex_array_put(fa, nr, (void *)&(src), gfp) |
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void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr); |
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#endif /* _FLEX_ARRAY_H */
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