From: Greg Kroah-Hartman <[EMAIL PROTECTED]>
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 <[EMAIL PROTECTED]>
---
drivers/usb/core/file.c | 70 ++++++++++++++++++++++++++++++++++++-----------
1 files changed, 54 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
index 7089871..f65b193 100644
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -61,33 +61,66 @@ static struct file_operations usb_fops =
.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 (error) {
- err("unable to get major %d for usb devices", USB_MAJOR);
- goto out;
+ if (usb_class != NULL) {
+ kref_get(&usb_class->kref);
+ goto exit;
+ }
+
+ usb_class = kmalloc(sizeof(*usb_class), GFP_KERNEL);
+ if (!usb_class) {
+ result = -ENOMEM;
+ goto exit;
}
- usb_class = class_create(THIS_MODULE, "usb");
- if (IS_ERR(usb_class)) {
- error = PTR_ERR(usb_class);
+ kref_init(&usb_class->kref);
+ usb_class->class = class_create(THIS_MODULE, "usb");
+ if (IS_ERR(usb_class->class)) {
+ result = IS_ERR(usb_class->class);
err("class_create failed for usb devices");
- unregister_chrdev(USB_MAJOR, "usb");
- goto out;
+ kfree(usb_class);
+ 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;
}
void usb_major_cleanup(void)
{
- class_destroy(usb_class);
unregister_chrdev(USB_MAJOR, "usb");
}
@@ -149,6 +182,10 @@ #endif
if (retval)
goto exit;
+ retval = init_usb_class();
+ if (retval)
+ goto exit;
+
intf->minor = minor;
/* create a usb class device for this usb interface */
@@ -158,7 +195,7 @@ #endif
++temp;
else
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);
if (IS_ERR(intf->usb_dev)) {
spin_lock (&minor_lock);
@@ -205,9 +242,10 @@ #endif
spin_unlock (&minor_lock);
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->minor = -1;
+ destroy_usb_class();
}
EXPORT_SYMBOL(usb_deregister_dev);
--
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