container_of.h

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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_CONTAINER_OF_H
#define _LINUX_CONTAINER_OF_H
 
#include <linux/build_bug.h>
#include <linux/stddef.h>
 
#define typeof_member(T, m) typeof(((T*)0)->m)
 
#define container_of(ptr, type, member) ({              \
    void *__mptr = (void *)(ptr);                   \
    static_assert(__same_type(*(ptr), ((type *)0)->member) ||   \
              __same_type(*(ptr), void),            \
              "pointer type mismatch in container_of()");   \
    ((type *)(__mptr - offsetof(type, member))); })
 
#define container_of_const(ptr, type, member)               \
    _Generic(ptr,                           \
        const typeof(*(ptr)) *: ((const type *)container_of(ptr, type, member)),\
        default: ((type *)container_of(ptr, type, member))  \
    )
 
#endif  /* _LINUX_CONTAINER_OF_H */