1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2
3
4#ifndef __always_inline
5#define __always_inline __inline__
6#endif
7
8/**
9 * __struct_group() - Create a mirrored named and anonyomous struct
10 *
11 * @TAG: The tag name for the named sub-struct (usually empty)
12 * @NAME: The identifier name of the mirrored sub-struct
13 * @ATTRS: Any struct attributes (usually empty)
14 * @MEMBERS: The member declarations for the mirrored structs
15 *
16 * Used to create an anonymous union of two structs with identical layout
17 * and size: one anonymous and one named. The former's members can be used
18 * normally without sub-struct naming, and the latter can be used to
19 * reason about the start, end, and size of the group of struct members.
20 * The named struct can also be explicitly tagged for layer reuse, as well
21 * as both having struct attributes appended.
22 */
23#define __struct_group(TAG, NAME, ATTRS, MEMBERS...) \
24 union { \
25 struct { MEMBERS } ATTRS; \
26 struct TAG { MEMBERS } ATTRS NAME; \
27 }
28
29/**
30 * __DECLARE_FLEX_ARRAY() - Declare a flexible array usable in a union
31 *
32 * @TYPE: The type of each flexible array element
33 * @NAME: The name of the flexible array member
34 *
35 * In order to have a flexible array member in a union or alone in a
36 * struct, it needs to be wrapped in an anonymous struct with at least 1
37 * named member, but that member can be empty.
38 */
39#define __DECLARE_FLEX_ARRAY(TYPE, NAME) \
40 struct { \
41 struct { } __empty_ ## NAME; \
42 TYPE NAME[]; \
43 }
44