1. 根目录:
2. include
3. linux
4. unaligned
5. packed_struct.h

#ifndef _LINUX_UNALIGNED_PACKED_STRUCT_H
#define _LINUX_UNALIGNED_PACKED_STRUCT_H

#include <linux/kernel.h>

struct __una_u16 { u16 x; } __packed;
struct __una_u32 { u32 x; } __packed;
struct __una_u64 { u64 x; } __packed;

static inline u16 __get_unaligned_cpu16(const void *p)
{
	const struct __una_u16 *ptr = (const struct __una_u16 *)p;
	return ptr->x;
}

static inline u32 __get_unaligned_cpu32(const void *p)
{
	const struct __una_u32 *ptr = (const struct __una_u32 *)p;
	return ptr->x;
}

static inline u64 __get_unaligned_cpu64(const void *p)
{
	const struct __una_u64 *ptr = (const struct __una_u64 *)p;
	return ptr->x;
}

static inline void __put_unaligned_cpu16(u16 val, void *p)
{
	struct __una_u16 *ptr = (struct __una_u16 *)p;
	ptr->x = val;
}

static inline void __put_unaligned_cpu32(u32 val, void *p)
{
	struct __una_u32 *ptr = (struct __una_u32 *)p;
	ptr->x = val;
}

static inline void __put_unaligned_cpu64(u64 val, void *p)
{
	struct __una_u64 *ptr = (struct __una_u64 *)p;
	ptr->x = val;
}

#endif /* _LINUX_UNALIGNED_PACKED_STRUCT_H */