mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 13:43:55 +08:00
45b588d6e5
FLEX_ARRAY_INIT(element_size, total_nr_elements) cannot determine if either parameter is valid, so flex arrays which are statically allocated with this interface can easily become corrupted or reference beyond its allocated memory. This removes FLEX_ARRAY_INIT() as a struct flex_array initializer since no initializer may perform the required checking. Instead, the array is now defined with a new interface: DEFINE_FLEX_ARRAY(name, element_size, total_nr_elements) This may be prefixed with `static' for file scope. This interface includes compile-time checking of the parameters to ensure they are valid. Since the validity of both element_size and total_nr_elements depend on FLEX_ARRAY_BASE_SIZE and FLEX_ARRAY_PART_SIZE, the kernel build will fail if either of these predefined values changes such that the array parameters are no longer valid. Since BUILD_BUG_ON() requires compile time constants, several of the static inline functions that were once local to lib/flex_array.c had to be moved to include/linux/flex_array.h. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
74 lines
2.2 KiB
C
74 lines
2.2 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);
|
|
|
|
#endif /* _FLEX_ARRAY_H */
|