#ifndef _FLEX_ARRAY_H #define _FLEX_ARRAY_H #include <linux/types.h> #include <asm/page.h> #define FLEX_ARRAY_PART_SIZE PAGE_SIZE #define FLEX_ARRAY_BASE_SIZE PAGE_SIZE struct flex_array_part; /* * This is meant to replace cases where an array-like * structure has gotten too big to fit into kmalloc() * and the developer is getting tempted to use * vmalloc(). */ struct flex_array { union { struct { int element_size; int total_nr_elements; int elems_per_part; u32 reciprocal_elems; struct flex_array_part *parts[]; }; /* * This little trick makes sure that * sizeof(flex_array) == PAGE_SIZE */ char padding[FLEX_ARRAY_BASE_SIZE]; }; }; /* Number of bytes left in base struct flex_array, excluding metadata */ #define FLEX_ARRAY_BASE_BYTES_LEFT \ (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) /* Number of pointers in base to struct flex_array_part pages */ #define FLEX_ARRAY_NR_BASE_PTRS \ (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) /* Number of elements of size that fit in struct flex_array_part */ #define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ (FLEX_ARRAY_PART_SIZE / size) /* * Defines a statically allocated flex array and ensures its parameters are * valid. */ #define DEFINE_FLEX_ARRAY(__arrayname, __element_size, __total) \ struct flex_array __arrayname = { { { \ .element_size = (__element_size), \ .total_nr_elements = (__total), \ } } }; \ static inline void __arrayname##_invalid_parameter(void) \ { \ BUILD_BUG_ON((__total) > FLEX_ARRAY_NR_BASE_PTRS * \ FLEX_ARRAY_ELEMENTS_PER_PART(__element_size)); \ } struct flex_array *flex_array_alloc(int element_size, unsigned int total, gfp_t flags); int flex_array_prealloc(struct flex_array *fa, unsigned int start, unsigned int nr_elements, gfp_t flags); void flex_array_free(struct flex_array *fa); void flex_array_free_parts(struct flex_array *fa); int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src, gfp_t flags); int flex_array_clear(struct flex_array *fa, unsigned int element_nr); void *flex_array_get(struct flex_array *fa, unsigned int element_nr); int flex_array_shrink(struct flex_array *fa); #define flex_array_put_ptr(fa, nr, src, gfp) \ flex_array_put(fa, nr, (void *)&(src), gfp) void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr); #endif /* _FLEX_ARRAY_H */