6 files changed, 140 insertions, 1 deletions

diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
index d5503cf0bf74..dd1c4d2a0c31 100644
--- a/drivers/usb/core/Makefile
+++ b/drivers/usb/core/Makefile
@@ -3,7 +3,7 @@
 #
 
 usbcore-objs    := usb.o hub.o hcd.o urb.o message.o \
-                        config.o file.o buffer.o sysfs.o devio.o
+                        config.o file.o buffer.o sysfs.o devio.o notify.o
 
 ifeq ($(CONFIG_PCI),y)
         usbcore-objs    += hcd-pci.o
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 9ad3912a5ed7..b700b6cdb683 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -792,6 +792,7 @@ static int usb_register_bus(struct usb_bus *bus)
         list_add (&bus->bus_list, &usb_bus_list);
         up (&usb_bus_list_lock);
 
+        usb_notify_add_bus(bus);
         usbfs_add_bus (bus);
         usbmon_notify_bus_add (bus);
 
@@ -820,6 +821,7 @@ static void usb_deregister_bus (struct usb_bus *bus)
         list_del (&bus->bus_list);
         up (&usb_bus_list_lock);
 
+        usb_notify_remove_bus(bus);
         usbmon_notify_bus_remove (bus);
         usbfs_remove_bus (bus);
 
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 273e6ccca213..4f1a8c8cf92b 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1128,6 +1128,8 @@ void usb_disconnect(struct usb_device **pdev)
          */
         usb_disable_device(udev, 0);
 
+        usb_notify_remove_device(udev);
+
         /* Free the device number, remove the /proc/bus/usb entry and
          * the sysfs attributes, and delete the parent's children[]
          * (or root_hub) pointer.
@@ -1371,6 +1373,7 @@ int usb_new_device(struct usb_device *udev)
         }
 
         /* USB device state == configured ... usable */
+        usb_notify_add_device(udev);
 
         /* add a /proc/bus/usb entry */
         usbdev_add(udev);
diff --git a/drivers/usb/core/notify.c b/drivers/usb/core/notify.c
new file mode 100644
index 000000000000..37da059eced7
--- /dev/null
+++ b/drivers/usb/core/notify.c
@@ -0,0 +1,120 @@
+/*
+ * All the USB notify logic
+ *
+ * (C) Copyright 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ *
+ * notifier functions originally based on those in kernel/sys.c
+ * but fixed up to not be so broken.
+ *
+ */
+
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/notifier.h>
+#ifdef CONFIG_USB_DEBUG
+        #define DEBUG
+#else
+        #undef DEBUG
+#endif
+#include <linux/usb.h>
+
+#include "usb.h"
+
+
+static struct notifier_block *usb_notifier_list;
+static DECLARE_MUTEX(usb_notifier_lock);
+
+static void usb_notifier_chain_register(struct notifier_block **list,
+                                        struct notifier_block *n)
+{
+        down(&usb_notifier_lock);
+        while (*list) {
+                if (n->priority > (*list)->priority)
+                        break;
+                list = &((*list)->next);
+        }
+        n->next = *list;
+        *list = n;
+        up(&usb_notifier_lock);
+}
+
+static void usb_notifier_chain_unregister(struct notifier_block **nl,
+                                   struct notifier_block *n)
+{
+        down(&usb_notifier_lock);
+        while ((*nl)!=NULL) {
+                if ((*nl)==n) {
+                        *nl = n->next;
+                        goto exit;
+                }
+                nl=&((*nl)->next);
+        }
+exit:
+        up(&usb_notifier_lock);
+}
+
+static int usb_notifier_call_chain(struct notifier_block **n,
+                                   unsigned long val, void *v)
+{
+        int ret=NOTIFY_DONE;
+        struct notifier_block *nb = *n;
+
+        down(&usb_notifier_lock);
+        while (nb) {
+                ret = nb->notifier_call(nb,val,v);
+                if (ret&NOTIFY_STOP_MASK) {
+                        goto exit;
+                }
+                nb = nb->next;
+        }
+exit:
+        up(&usb_notifier_lock);
+        return ret;
+}
+
+/**
+ * usb_register_notify - register a notifier callback whenever a usb change happens
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * These changes are either USB devices or busses being added or removed.
+ */
+void usb_register_notify(struct notifier_block *nb)
+{
+        usb_notifier_chain_register(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_register_notify);
+
+/**
+ * usb_unregister_notify - unregister a notifier callback
+ * @nb: pointer to the notifier block for the callback events.
+ *
+ * usb_register_notifier() must have been previously called for this function
+ * to work properly.
+ */
+void usb_unregister_notify(struct notifier_block *nb)
+{
+        usb_notifier_chain_unregister(&usb_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(usb_unregister_notify);
+
+
+void usb_notify_add_device(struct usb_device *udev)
+{
+        usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_ADD, udev);
+}
+
+void usb_notify_remove_device(struct usb_device *udev)
+{
+        usb_notifier_call_chain(&usb_notifier_list, USB_DEVICE_REMOVE, udev);
+}
+
+void usb_notify_add_bus(struct usb_bus *ubus)
+{
+        usb_notifier_call_chain(&usb_notifier_list, USB_BUS_ADD, ubus);
+}
+
+void usb_notify_remove_bus(struct usb_bus *ubus)
+{
+        usb_notifier_call_chain(&usb_notifier_list, USB_BUS_REMOVE, ubus);
+}
diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
index 3dc8096c0f92..811cf4482e0d 100644
--- a/drivers/usb/core/usb.h
+++ b/drivers/usb/core/usb.h
@@ -80,3 +80,9 @@ struct dev_state {
         unsigned long ifclaimed;
 };
 
+/* internal notify stuff */
+extern void usb_notify_add_device(struct usb_device *udev);
+extern void usb_notify_remove_device(struct usb_device *udev);
+extern void usb_notify_add_bus(struct usb_bus *ubus);
+extern void usb_notify_remove_bus(struct usb_bus *ubus);
+
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 207b1ad9d990..a2d923fd54f9 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -1135,6 +1135,14 @@ usb_maxpacket(struct usb_device *udev, int pipe, int is_out)
 
 /* -------------------------------------------------------------------------- */
 
+/* Events from the usb core */
+#define USB_DEVICE_ADD          0x0001
+#define USB_DEVICE_REMOVE       0x0002
+#define USB_BUS_ADD             0x0003
+#define USB_BUS_REMOVE          0x0004
+extern void usb_register_notify(struct notifier_block *nb);
+extern void usb_unregister_notify(struct notifier_block *nb);
+
 #ifdef DEBUG
 #define dbg(format, arg...) printk(KERN_DEBUG "%s: " format "\n" , __FILE__ , ## arg)
 #else