linux内核加载时fops

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 *);
    int (*open) (struct inode *, struct file *);
    int (*release) (struct inode *, struct file *);
    // 其他操作...
};

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>

static int my_open(struct inode *inode, struct file *file) {
    printk(KERN_INFO "My device opened\n");
    return 0;
}

static int my_release(struct inode *inode, struct file *file) {
    printk(KERN_INFO "My device closed\n");
    return 0;
}

static ssize_t my_read(struct file *file, char __user *buffer, size_t length, loff_t *offset) {
    printk(KERN_INFO "Reading from my device\n");
    return 0;
}

static ssize_t my_write(struct file *file, const char __user *buffer, size_t length, loff_t *offset) {
    printk(KERN_INFO "Writing to my device\n");
    return length;
}

static struct file_operations my_fops = {
    .open = my_open,
    .release = my_release,
    .read = my_read,
    .write = my_write,
};

static int __init my_init(void) {
    register_chrdev(240, "my_device", &my_fops);
    printk(KERN_INFO "My device registered\n");
    return 0;
}

static void __exit my_exit(void) {
    unregister_chrdev(240, "my_device");
    printk(KERN_INFO "My device unregistered\n");
}

module_init(my_init);
module_exit(my_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("A simple character device driver");