forked from luck/tmp_suning_uos_patched
ea98eed9bc
Getting and putting arrays of pointers with flex arrays is a PITA. You have to remember to pass &ptr to the _put and you have to do weird and wacky casting to get the ptr back from the _get. Add two functions flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic. [akpm@linux-foundation.org: simplification suggested by Joe] Signed-off-by: Eric Paris <eparis@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Joe Perches <joe@perches.com> Cc: James Morris <jmorris@namei.org> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
#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;
|
|
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 end, 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 */
|