Как при создании своего символьного устройства в модуле ядра linux, сделать так чтоб его состояние могло отслеживаться мультиплексорами io?

Для регистрации операций с символьными устройствами используется структура file_operations, ее код в моей версии ос приведен ниже. Какие процедуры из этой структуры мне нужно реализовать, чтоб состояние дескриптора моего символьного устройства можно было отслеживать через select/poll/epoll. Буду очень благодарен за короткий пример.

   struct file_operations {
        struct module *owner;
        loff_t (*llseek) (struct file *, loff_t, int);
        ssize_t (*read) (struct file *, char __user *, size_t, loff_t *);
        ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
        ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
        ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
        int (*iopoll)(struct kiocb *kiocb, bool spin);
        int (*iterate) (struct file *, struct dir_context *);
        int (*iterate_shared) (struct file *, struct dir_context *);
        __poll_t (*poll) (struct file *, struct poll_table_struct *);
        long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
        long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
        int (*mmap) (struct file *, struct vm_area_struct *);
        unsigned long mmap_supported_flags;
        int (*open) (struct inode *, struct file *);
        int (*flush) (struct file *, fl_owner_t id);
        int (*release) (struct inode *, struct file *);
        int (*fsync) (struct file *, loff_t, loff_t, int datasync);
        int (*fasync) (int, struct file *, int);
        int (*lock) (struct file *, int, struct file_lock *);
        ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
        unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
        int (*check_flags)(int);
        int (*setfl)(struct file *, unsigned long);
        int (*flock) (struct file *, int, struct file_lock *);
        ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, loff_t *, size_t, unsigned int);
        ssize_t (*splice_read)(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int);
        int (*setlease)(struct file *, long, struct file_lock **, void **);
        long (*fallocate)(struct file *file, int mode, loff_t offset,
                  loff_t len);
        void (*show_fdinfo)(struct seq_file *m, struct file *f);
    #ifndef CONFIG_MMU
        unsigned (*mmap_capabilities)(struct file *);
    #endif
        ssize_t (*copy_file_range)(struct file *, loff_t, struct file *,
                loff_t, size_t, unsigned int);
        loff_t (*remap_file_range)(struct file *file_in, loff_t pos_in,
                       struct file *file_out, loff_t pos_out,
                       loff_t len, unsigned int remap_flags);
        int (*fadvise)(struct file *, loff_t, loff_t, int);
    } __randomize_layout;
    
    struct inode_operations {
        struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
        const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
        int (*permission) (struct user_namespace *, struct inode *, int);
        struct posix_acl * (*get_acl)(struct inode *, int, bool);
    
        int (*readlink) (struct dentry *, char __user *,int);
    
        int (*create) (struct user_namespace *, struct inode *,struct dentry *,
                   umode_t, bool);
        int (*link) (struct dentry *,struct inode *,struct dentry *);
        int (*unlink) (struct inode *,struct dentry *);
        int (*symlink) (struct user_namespace *, struct inode *,struct dentry *,
                const char *);
        int (*mkdir) (struct user_namespace *, struct inode *,struct dentry *,
                  umode_t);
        int (*rmdir) (struct inode *,struct dentry *);
        int (*mknod) (struct user_namespace *, struct inode *,struct dentry *,
                  umode_t,dev_t);
        int (*rename) (struct user_namespace *, struct inode *, struct dentry *,
                struct inode *, struct dentry *, unsigned int);
        int (*setattr) (struct user_namespace *, struct dentry *,
                struct iattr *);
        int (*getattr) (struct user_namespace *, const struct path *,
                struct kstat *, u32, unsigned int);
        ssize_t (*listxattr) (struct dentry *, char *, size_t);
        int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start,
                  u64 len);
        int (*update_time)(struct inode *, struct timespec64 *, int);
        int (*atomic_open)(struct inode *, struct dentry *,
                   struct file *, unsigned open_flag,
                   umode_t create_mode);
        int (*tmpfile) (struct user_namespace *, struct inode *,
                struct dentry *, umode_t);
        int (*set_acl)(struct user_namespace *, struct inode *,
                   struct posix_acl *, int);
        int (*fileattr_set)(struct user_namespace *mnt_userns,
                    struct dentry *dentry, struct fileattr *fa);
        int (*fileattr_get)(struct dentry *dentry, struct fileattr *fa);
    } ____cacheline_aligned;