[PATCH] USB: only make /sys/class/usb show up when there is something in it
Now /sys/class/usb is dynamically created when we have something to put in it, and removed when all devices go away. Just trying to cut down on the clutter in sysfs... Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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parent
bd00949647
commit
43104f1da8
1 changed files with 54 additions and 16 deletions
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@ -61,33 +61,66 @@ static struct file_operations usb_fops = {
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.open = usb_open,
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.open = usb_open,
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};
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};
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static struct class *usb_class;
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static struct usb_class {
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struct kref kref;
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struct class *class;
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} *usb_class;
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static int init_usb_class(void)
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{
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int result = 0;
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if (usb_class != NULL) {
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kref_get(&usb_class->kref);
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goto exit;
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}
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usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
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if (!usb_class) {
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result = -ENOMEM;
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goto exit;
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}
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kref_init(&usb_class->kref);
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usb_class->class = class_create(THIS_MODULE, "usb");
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if (IS_ERR(usb_class->class)) {
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result = IS_ERR(usb_class->class);
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err("class_create failed for usb devices");
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kfree(usb_class);
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usb_class = NULL;
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}
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exit:
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return result;
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}
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static void release_usb_class(struct kref *kref)
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{
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/* Ok, we cheat as we know we only have one usb_class */
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class_destroy(usb_class->class);
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kfree(usb_class);
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usb_class = NULL;
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}
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static void destroy_usb_class(void)
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{
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if (usb_class)
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kref_put(&usb_class->kref, release_usb_class);
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}
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int usb_major_init(void)
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int usb_major_init(void)
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{
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{
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int error;
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int error;
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error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
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error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
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if (error) {
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if (error)
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err("unable to get major %d for usb devices", USB_MAJOR);
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err("unable to get major %d for usb devices", USB_MAJOR);
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goto out;
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}
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usb_class = class_create(THIS_MODULE, "usb");
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if (IS_ERR(usb_class)) {
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error = PTR_ERR(usb_class);
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err("class_create failed for usb devices");
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unregister_chrdev(USB_MAJOR, "usb");
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goto out;
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}
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out:
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return error;
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return error;
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}
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}
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void usb_major_cleanup(void)
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void usb_major_cleanup(void)
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{
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{
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class_destroy(usb_class);
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unregister_chrdev(USB_MAJOR, "usb");
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unregister_chrdev(USB_MAJOR, "usb");
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}
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}
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@ -146,6 +179,10 @@ int usb_register_dev(struct usb_interface *intf,
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}
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}
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spin_unlock (&minor_lock);
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spin_unlock (&minor_lock);
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if (retval)
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goto exit;
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retval = init_usb_class();
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if (retval)
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if (retval)
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goto exit;
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goto exit;
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@ -158,7 +195,7 @@ int usb_register_dev(struct usb_interface *intf,
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++temp;
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++temp;
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else
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else
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temp = name;
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temp = name;
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intf->usb_dev = device_create(usb_class, &intf->dev,
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intf->usb_dev = device_create(usb_class->class, &intf->dev,
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MKDEV(USB_MAJOR, minor), "%s", temp);
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MKDEV(USB_MAJOR, minor), "%s", temp);
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if (IS_ERR(intf->usb_dev)) {
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if (IS_ERR(intf->usb_dev)) {
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spin_lock (&minor_lock);
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spin_lock (&minor_lock);
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@ -205,9 +242,10 @@ void usb_deregister_dev(struct usb_interface *intf,
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spin_unlock (&minor_lock);
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spin_unlock (&minor_lock);
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snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
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snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
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device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor));
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device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
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intf->usb_dev = NULL;
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intf->usb_dev = NULL;
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intf->minor = -1;
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intf->minor = -1;
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destroy_usb_class();
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}
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}
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EXPORT_SYMBOL(usb_deregister_dev);
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EXPORT_SYMBOL(usb_deregister_dev);
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