include/linux/flex_array.h

   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;
  24                         struct flex_array_part *parts[];
  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
  34 #define FLEX_ARRAY_INIT(size, total) { { {\
  35         .element_size = (size),         \
  36         .total_nr_elements = (total),   \
  37 } } }
  38
  39 struct flex_array *flex_array_alloc(int element_size, unsigned int total,
  40                 gfp_t flags);
  41 int flex_array_prealloc(struct flex_array *fa, unsigned int start,
  42                 unsigned int end, gfp_t flags);
  43 void flex_array_free(struct flex_array *fa);
  44 void flex_array_free_parts(struct flex_array *fa);
  45 int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
  46                 gfp_t flags);
  47 void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
  48
  49 #endif /* _FLEX_ARRAY_H */