创建kobject

news2024/10/7 8:20:07

1、kobject介绍

kobject的全称是kernel object，即内核对象。每一个kobject都会对应系统/sys/下的一个目录。
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2、相关结构体和api介绍

2.1 struct kobject

// include/linux/kobject.h
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2.2 kobject_create_and_add

kobject_create_and_add
	kobject_create
	kobject_add
		kobject_add_varg

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2.3 kobject_init_and_add

kobject_init_and_add
	kobject_init
		kobject_init_internal
	kobject_add_varg

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2.4 kobject_put

kobject_put
	kref_put
		kref_sub

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3、实验操作

#include<linux/module.h>
#include<linux/init.h>
#include<linux/kernel.h>
#include<linux/kobject.h>
#include<linux/slab.h>

struct kobject *my_kobject01;
struct kobject *my_kobject02;
struct kobject *my_kobject03;
struct kobj_type mytype;

/*
创建kobject的两种方法：
1、kobject_create_and_add
2、kzalloc->kobject_init_and_add
*/
static int my_kobject_init(void)
{
     int ret;
     my_kobject01 = kobject_create_and_add("my_kobject01",NULL); // /sys/my_kobject01
     my_kobject02 = kobject_create_and_add("my_kobject02",my_kobject01); // /sys/my_kobject01/my_kobject02
     
     my_kobject03 = kzalloc(sizeof(struct kobject),GFP_KERNEL);
     ret = kobject_init_and_add(my_kobject03,&mytype,NULL,"%s","my_kobject03");// /sys/my_kobject03
     return 0;
}

static void my_kobject_exit(void)
{
     kobject_put(my_kobject01);
     kobject_put(my_kobject02);
     kobject_put(my_kobject03);
}

module_init(my_kobject_init);
module_exit(my_kobject_exit);
MODULE_LICENSE("GPL");

//Makefile
obj-m += kobject.o
KDIR := /home/johan/share/rk3588/linux_sdk/kernel
PWD ?= $(shell pwd)
all:
	make -C $(KDIR) M=$(PWD) modules
	

clean:
	rm -f *.ko *.o *.mod.o *.mod.c