linux設備模型: kobject, kset

kobject

linux3.4

struct kobject {
	const char		*name;  
	struct list_head	entry;   // directory entry, used for mount to kset list,
	struct kobject		*parent;  
	struct kset		*kset;       
	struct kobj_type	*ktype;   //指向對象類型描述附指針
	struct sysfs_dirent	*sd;      //
	struct kref		kref;         // 引用計數
	unsigned int state_initialized:1;
	unsigned int state_in_sysfs:1;
	unsigned int state_add_uevent_sent:1;
	unsigned int state_remove_uevent_sent:1;
	unsigned int uevent_suppress:1;
};

其中 sysfs_dirent,

/*
 * sysfs_dirent - the building block of sysfs hierarchy.  Each and
 * every sysfs node is represented by single sysfs_dirent.
 *
 * As long as s_count reference is held, the sysfs_dirent itself is
 * accessible.  Dereferencing s_elem or any other outer entity
 * requires s_active reference.
 */
struct sysfs_dirent {
	atomic_t		s_count;
	atomic_t		s_active;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
	struct lockdep_map	dep_map;
#endif
	struct sysfs_dirent	*s_parent;
	const char		*s_name;

	struct rb_node		s_rb;

	union {
		struct completion	*completion;
		struct sysfs_dirent	*removed_list;
	} u;

	const void		*s_ns; /* namespace tag */
	unsigned int		s_hash; /* ns + name hash */
	union {
		struct sysfs_elem_dir		s_dir;
		struct sysfs_elem_symlink	s_symlink;
		struct sysfs_elem_attr		s_attr;
		struct sysfs_elem_bin_attr	s_bin_attr;
	};

	unsigned short		s_flags;
	umode_t 		s_mode;
	unsigned int		s_ino;
	struct sysfs_inode_attrs *s_iattr;
};

kset

struct kset {
	struct list_head list; //double list head
	spinlock_t list_lock;  
	struct kobject kobj;  //嵌入的kobject
	const struct kset_uevent_ops *uevent_ops;  //事件操作集
};

其中 kset_uevent_ops 定義了kset的對所包含的kobject 可以執行的操作，包括事件過濾和導出環境變量操作。

struct kset_uevent_ops {
	int (* const filter)(struct kset *kset, struct kobject *kobj);  //事件過濾
	const char *(* const name)(struct kset *kset, struct kobject *kobj); 
	int (* const uevent)(struct kset *kset, struct kobject *kobj,
		      struct kobj_uevent_env *env);   // 環境變量導出 
};

kobject 與sysfs 的關係

想要把kobject 導入sysfs，需要：

int kobject_add(struct kobject *obj,...)

kobject

kobject 與事件消息傳遞

netlink

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