Commit 43104f1d authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman

[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: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent bd009496
...@@ -61,33 +61,66 @@ static struct file_operations usb_fops = { ...@@ -61,33 +61,66 @@ static struct file_operations usb_fops = {
.open = usb_open, .open = usb_open,
}; };
static struct class *usb_class; static struct usb_class {
struct kref kref;
struct class *class;
} *usb_class;
int usb_major_init(void) static int init_usb_class(void)
{ {
int error; int result = 0;
error = register_chrdev(USB_MAJOR, "usb", &usb_fops); if (usb_class != NULL) {
if (error) { kref_get(&usb_class->kref);
err("unable to get major %d for usb devices", USB_MAJOR); goto exit;
goto out; }
usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
if (!usb_class) {
result = -ENOMEM;
goto exit;
} }
usb_class = class_create(THIS_MODULE, "usb"); kref_init(&usb_class->kref);
if (IS_ERR(usb_class)) { usb_class->class = class_create(THIS_MODULE, "usb");
error = PTR_ERR(usb_class); if (IS_ERR(usb_class->class)) {
result = IS_ERR(usb_class->class);
err("class_create failed for usb devices"); err("class_create failed for usb devices");
unregister_chrdev(USB_MAJOR, "usb"); kfree(usb_class);
goto out; usb_class = NULL;
} }
out: exit:
return result;
}
static void release_usb_class(struct kref *kref)
{
/* Ok, we cheat as we know we only have one usb_class */
class_destroy(usb_class->class);
kfree(usb_class);
usb_class = NULL;
}
static void destroy_usb_class(void)
{
if (usb_class)
kref_put(&usb_class->kref, release_usb_class);
}
int usb_major_init(void)
{
int error;
error = register_chrdev(USB_MAJOR, "usb", &usb_fops);
if (error)
err("unable to get major %d for usb devices", USB_MAJOR);
return error; return error;
} }
void usb_major_cleanup(void) void usb_major_cleanup(void)
{ {
class_destroy(usb_class);
unregister_chrdev(USB_MAJOR, "usb"); unregister_chrdev(USB_MAJOR, "usb");
} }
...@@ -146,6 +179,10 @@ int usb_register_dev(struct usb_interface *intf, ...@@ -146,6 +179,10 @@ int usb_register_dev(struct usb_interface *intf,
} }
spin_unlock (&minor_lock); spin_unlock (&minor_lock);
if (retval)
goto exit;
retval = init_usb_class();
if (retval) if (retval)
goto exit; goto exit;
...@@ -158,7 +195,7 @@ int usb_register_dev(struct usb_interface *intf, ...@@ -158,7 +195,7 @@ int usb_register_dev(struct usb_interface *intf,
++temp; ++temp;
else else
temp = name; temp = name;
intf->usb_dev = device_create(usb_class, &intf->dev, intf->usb_dev = device_create(usb_class->class, &intf->dev,
MKDEV(USB_MAJOR, minor), "%s", temp); MKDEV(USB_MAJOR, minor), "%s", temp);
if (IS_ERR(intf->usb_dev)) { if (IS_ERR(intf->usb_dev)) {
spin_lock (&minor_lock); spin_lock (&minor_lock);
...@@ -205,9 +242,10 @@ void usb_deregister_dev(struct usb_interface *intf, ...@@ -205,9 +242,10 @@ void usb_deregister_dev(struct usb_interface *intf,
spin_unlock (&minor_lock); spin_unlock (&minor_lock);
snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base); snprintf(name, BUS_ID_SIZE, class_driver->name, intf->minor - minor_base);
device_destroy(usb_class, MKDEV(USB_MAJOR, intf->minor)); device_destroy(usb_class->class, MKDEV(USB_MAJOR, intf->minor));
intf->usb_dev = NULL; intf->usb_dev = NULL;
intf->minor = -1; intf->minor = -1;
destroy_usb_class();
} }
EXPORT_SYMBOL(usb_deregister_dev); EXPORT_SYMBOL(usb_deregister_dev);
......
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