4 files changed, 61 insertions, 0 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 7d8a7ce73fb3..ed3e8a2be64a 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -724,6 +724,8 @@ int bus_register(struct bus_type * bus)
 {
         int retval;
 
+        BLOCKING_INIT_NOTIFIER_HEAD(&bus->bus_notifier);
+
         retval = kobject_set_name(&bus->subsys.kset.kobj, "%s", bus->name);
         if (retval)
                 goto out;
@@ -782,6 +784,18 @@ void bus_unregister(struct bus_type * bus)
         subsystem_unregister(&bus->subsys);
 }
 
+int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_register_notifier);
+
+int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
+{
+        return blocking_notifier_chain_unregister(&bus->bus_notifier, nb);
+}
+EXPORT_SYMBOL_GPL(bus_unregister_notifier);
+
 int __init buses_init(void)
 {
         return subsystem_register(&bus_subsys);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 002fde46d38d..d4f35d8902a2 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/kdev_t.h>
+#include <linux/notifier.h>
 
 #include <asm/semaphore.h>
 
@@ -428,6 +429,11 @@ int device_add(struct device *dev)
         if (platform_notify)
                 platform_notify(dev);
 
+        /* notify clients of device entry (new way) */
+        if (dev->bus)
+                blocking_notifier_call_chain(&dev->bus->bus_notifier,
+                                             BUS_NOTIFY_ADD_DEVICE, dev);
+
         dev->uevent_attr.attr.name = "uevent";
         dev->uevent_attr.attr.mode = S_IWUSR;
         if (dev->driver)
@@ -504,6 +510,9 @@ int device_add(struct device *dev)
  BusError:
         device_pm_remove(dev);
  PMError:
+        if (dev->bus)
+                blocking_notifier_call_chain(&dev->bus->bus_notifier,
+                                             BUS_NOTIFY_DEL_DEVICE, dev);
         device_remove_groups(dev);
  GroupError:
         device_remove_attrs(dev);
@@ -622,6 +631,9 @@ void device_del(struct device * dev)
          */
         if (platform_notify_remove)
                 platform_notify_remove(dev);
+        if (dev->bus)
+                blocking_notifier_call_chain(&dev->bus->bus_notifier,
+                                             BUS_NOTIFY_DEL_DEVICE, dev);
         bus_remove_device(dev);
         device_pm_remove(dev);
         kobject_uevent(&dev->kobj, KOBJ_REMOVE);
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index c5d6bb4290ad..9c88b1e34bc3 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -52,6 +52,11 @@ int device_bind_driver(struct device *dev)
 
         pr_debug("bound device '%s' to driver '%s'\n",
                  dev->bus_id, dev->driver->name);
+
+        if (dev->bus)
+                blocking_notifier_call_chain(&dev->bus->bus_notifier,
+                                             BUS_NOTIFY_BOUND_DRIVER, dev);
+
         klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
         ret = sysfs_create_link(&dev->driver->kobj, &dev->kobj,
                           kobject_name(&dev->kobj));
@@ -288,6 +293,11 @@ static void __device_release_driver(struct device * dev)
                 sysfs_remove_link(&dev->kobj, "driver");
                 klist_remove(&dev->knode_driver);
 
+                if (dev->bus)
+                        blocking_notifier_call_chain(&dev->bus->bus_notifier,
+                                                     BUS_NOTIFY_UNBIND_DRIVER,
+                                                     dev);
+
                 if (dev->bus && dev->bus->remove)
                         dev->bus->remove(dev);
                 else if (drv->remove)
diff --git a/include/linux/device.h b/include/linux/device.h
index 9d4f6a963936..b00e02711393 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -42,6 +42,8 @@ struct bus_type {
         struct klist            klist_devices;
         struct klist            klist_drivers;
 
+        struct blocking_notifier_head bus_notifier;
+
         struct bus_attribute    * bus_attrs;
         struct device_attribute * dev_attrs;
         struct driver_attribute * drv_attrs;
@@ -75,6 +77,29 @@ int __must_check bus_for_each_drv(struct bus_type *bus,
                 struct device_driver *start, void *data,
                 int (*fn)(struct device_driver *, void *));
 
+/*
+ * Bus notifiers: Get notified of addition/removal of devices
+ * and binding/unbinding of drivers to devices.
+ * In the long run, it should be a replacement for the platform
+ * notify hooks.
+ */
+struct notifier_block;
+
+extern int bus_register_notifier(struct bus_type *bus,
+                                 struct notifier_block *nb);
+extern int bus_unregister_notifier(struct bus_type *bus,
+                                   struct notifier_block *nb);
+
+/* All 4 notifers below get called with the target struct device *
+ * as an argument. Note that those functions are likely to be called
+ * with the device semaphore held in the core, so be careful.
+ */
+#define BUS_NOTIFY_ADD_DEVICE           0x00000001 /* device added */
+#define BUS_NOTIFY_DEL_DEVICE           0x00000002 /* device removed */
+#define BUS_NOTIFY_BOUND_DRIVER         0x00000003 /* driver bound to device */
+#define BUS_NOTIFY_UNBIND_DRIVER        0x00000004 /* driver about to be
+                                                      unbound */
+
 /* driverfs interface for exporting bus attributes */
 
 struct bus_attribute {