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Release 4.12 include/linux/flex_array.h

Directory: include/linux
#ifndef _FLEX_ARRAY_H

#define _FLEX_ARRAY_H

#include <linux/types.h>
#include <linux/reciprocal_div.h>
#include <asm/page.h>



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;
struct reciprocal_value 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 */

	(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 */


 * 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));  \

 * flex_array_alloc() - Creates a flexible array.
 * @element_size:       individual object size.
 * @total:              maximum number of objects which can be stored.
 * @flags:              GFP flags
 * Return:              Returns an object of structure flex_array.
struct flex_array *flex_array_alloc(int element_size, unsigned int total,
		gfp_t flags);

 * flex_array_prealloc() - Ensures that memory for the elements indexed in the
 * range defined by start and nr_elements has been allocated.
 * @fa:                 array to allocate memory to.
 * @start:              start address
 * @nr_elements:        number of elements to be allocated.
 * @flags:              GFP flags
int flex_array_prealloc(struct flex_array *fa, unsigned int start,
		unsigned int nr_elements, gfp_t flags);

 * flex_array_free() - Removes all elements of a flexible array.
 * @fa:         array to be freed.
void flex_array_free(struct flex_array *fa);

 * flex_array_free_parts() - Removes all elements of a flexible array, but
 * leaves the array itself in place.
 * @fa:         array to be emptied.
void flex_array_free_parts(struct flex_array *fa);

 * flex_array_put() - Stores data into a flexible array.
 * @fa:         array where element is to be stored.
 * @element_nr: position to copy, must be less than the maximum specified when
 *              the array was created.
 * @src:        data source to be copied into the array.
 * @flags:      GFP flags
 * Return:      Returns zero on success, a negative error code otherwise.
int flex_array_put(struct flex_array *fa, unsigned int element_nr, void *src,
		gfp_t flags);

 * flex_array_clear() - Clears an individual element in the array, sets the
 * given element to FLEX_ARRAY_FREE.
 * @element_nr: element position to clear.
 * @fa:         array to which element to be cleared belongs.
 * Return:      Returns zero on success, -EINVAL otherwise.
int flex_array_clear(struct flex_array *fa, unsigned int element_nr);

 * flex_array_get() - Retrieves data into a flexible array.
 * @element_nr: Element position to retrieve data from.
 * @fa:         array from which data is to be retrieved.
 * Return:      Returns a pointer to the data element, or NULL if that
 *              particular element has never been allocated.
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);

 * flex_array_shrink() - Reduces the allocated size of an array.
 * @fa:         array to shrink.
 * Return:      Returns number of pages of memory actually freed.
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 */

Overall Contributors

Dave Hansen14658.63%18.33%
David Rientjes5622.49%541.67%
Eric Paris2911.65%325.00%
sayli karnik83.21%18.33%
Jesse Gross52.01%18.33%
Hannes Frederic Sowa52.01%18.33%
Directory: include/linux
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