driver core: Add BUS_NOTIFY_REMOVED_DEVICE event

This event closes an important gap in the bus notifiers.
There is already the BUS_NOTIFY_DEL_DEVICE event, but that
is sent when the device is still bound to its device driver.

This is too early for the IOMMU code to destroy any mappings
for the device, as they might still be in use by the driver.

The new BUS_NOTIFY_REMOVED_DEVICE event introduced with this
patch closes this gap as it is sent when the device is
already unbound from its device driver and almost completly
removed from the driver core.

With this event the IOMMU code can safely destroy any
mappings and other data structures when a device is removed.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Jerry Hoemann <jerry.hoemann@hp.com>

2 files changed, 9 insertions, 5 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 20da3ad1696b..7b270a2e6ed5 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1211,6 +1211,9 @@ void device_del(struct device *dev)
          */
         if (platform_notify_remove)
                 platform_notify_remove(dev);
+        if (dev->bus)
+                blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
+                                             BUS_NOTIFY_REMOVED_DEVICE, dev);
         kobject_uevent(&dev->kobj, KOBJ_REMOVE);
         cleanup_device_parent(dev);
         kobject_del(&dev->kobj);
diff --git a/include/linux/device.h b/include/linux/device.h
index 43d183aeb25b..d0d5c5db509d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -181,13 +181,14 @@ extern int bus_unregister_notifier(struct bus_type *bus,
  * with the device lock 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_BIND_DRIVER          0x00000003 /* driver about to be
+#define BUS_NOTIFY_DEL_DEVICE           0x00000002 /* device to be removed */
+#define BUS_NOTIFY_REMOVED_DEVICE       0x00000003 /* device removed */
+#define BUS_NOTIFY_BIND_DRIVER          0x00000004 /* driver about to be
                                                       bound */
-#define BUS_NOTIFY_BOUND_DRIVER         0x00000004 /* driver bound to device */
-#define BUS_NOTIFY_UNBIND_DRIVER        0x00000005 /* driver about to be
+#define BUS_NOTIFY_BOUND_DRIVER         0x00000005 /* driver bound to device */
+#define BUS_NOTIFY_UNBIND_DRIVER        0x00000006 /* driver about to be
                                                       unbound */
-#define BUS_NOTIFY_UNBOUND_DRIVER       0x00000006 /* driver is unbound
+#define BUS_NOTIFY_UNBOUND_DRIVER       0x00000007 /* driver is unbound
                                                       from the device */
 
 extern struct kset *bus_get_kset(struct bus_type *bus);