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d2a8ebbf AS |
1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_CONTAINER_OF_H | |
3 | #define _LINUX_CONTAINER_OF_H | |
4 | ||
5 | #include <linux/build_bug.h> | |
6 | #include <linux/err.h> | |
7 | ||
8 | #define typeof_member(T, m) typeof(((T*)0)->m) | |
9 | ||
10 | /** | |
11 | * container_of - cast a member of a structure out to the containing structure | |
12 | * @ptr: the pointer to the member. | |
13 | * @type: the type of the container struct this is embedded in. | |
14 | * @member: the name of the member within the struct. | |
15 | * | |
16 | */ | |
17 | #define container_of(ptr, type, member) ({ \ | |
18 | void *__mptr = (void *)(ptr); \ | |
e1edc277 RV |
19 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \ |
20 | __same_type(*(ptr), void), \ | |
21 | "pointer type mismatch in container_of()"); \ | |
d2a8ebbf AS |
22 | ((type *)(__mptr - offsetof(type, member))); }) |
23 | ||
24 | /** | |
25 | * container_of_safe - cast a member of a structure out to the containing structure | |
26 | * @ptr: the pointer to the member. | |
27 | * @type: the type of the container struct this is embedded in. | |
28 | * @member: the name of the member within the struct. | |
29 | * | |
30 | * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged. | |
31 | */ | |
32 | #define container_of_safe(ptr, type, member) ({ \ | |
33 | void *__mptr = (void *)(ptr); \ | |
e1edc277 RV |
34 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \ |
35 | __same_type(*(ptr), void), \ | |
36 | "pointer type mismatch in container_of_safe()"); \ | |
d2a8ebbf AS |
37 | IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \ |
38 | ((type *)(__mptr - offsetof(type, member))); }) | |
39 | ||
40 | #endif /* _LINUX_CONTAINER_OF_H */ |