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下面是一个创建简单的procfs文件节点的例子：

static ssize_t usb_hnp_show(struct file *file, char __user *user_buf,				     size_t count, loff_t *ppos){//	char *buf;	ssize_t ret;	struct usb_device *udev = global_usb_device;	if (udev == NULL)	{		printk(KERN_ERR "%s:the usb_device is NULL\n", __func__);		return -EFAULT;	}	dev_err(&udev->dev, "zsm %s\n", __func__);	return ret;}static ssize_t usb_hnp_store(struct file *file,				      const char __user *user_buf, size_t count,				      loff_t *ppos){	char buf[32];	ssize_t buf_size;	struct usb_device *udev = global_usb_device;	if (udev == NULL)	{		printk(KERN_ERR "%s:the usb_device is NULL\n", __func__);		return -EFAULT;	}	dev_err(&udev->dev, "zsm %s\n", __func__);	buf_size = min(count, (size_t)(sizeof(buf)-1));	if (copy_from_user(buf, user_buf, buf_size)) {		dev_err(&udev->dev, "Failed to copy from user\n");		return -EFAULT;	}	buf[buf_size] = 0;	return buf_size;}static const struct file_operations usb_hnp_node_fops = {	.owner = THIS_MODULE,	.open = simple_open,	.read = usb_hnp_show,	.write = usb_hnp_store,};

struct proc_dir_entry *usb_hnp_dentry;	usb_hnp_dentry = proc_create("enable_usb_hnp",					S_IRUGO, NULL, &usb_hnp_node_fops);

在/proc/下

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