[PATCH 2/10] sysdev: add error check in sysdev_register()

[Akinobu Mita <akinobu.mita@gmail.com>]

This patch enables to catch the errors returned by add() procedure of
sysdev driver in sysdev_register.

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

---
 drivers/base/sys.c |   48 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 10 deletions(-)

Index: 2.6-mm/drivers/base/sys.c
===================================================================
--- 2.6-mm.orig/drivers/base/sys.c
+++ 2.6-mm/drivers/base/sys.c
@@ -220,10 +220,13 @@ EXPORT_SYMBOL_GPL(sysdev_driver_unregist
  *	@sysdev:	device in question
  *
  */
-int sysdev_register(struct sys_device * sysdev)
+int sysdev_register(struct sys_device *sysdev)
 {
 	int error;
-	struct sysdev_class * cls = sysdev->cls;
+	struct sysdev_class *cls = sysdev->cls;
+	struct sysdev_driver *drv;
+	int added_sysdev = 0;
+	int added_cls = 0;
 
 	if (!cls)
 		return -EINVAL;
@@ -244,8 +247,6 @@ int sysdev_register(struct sys_device * 
 	error = kobject_register(&sysdev->kobj);
 
 	if (!error) {
-		struct sysdev_driver * drv;
-
 		mutex_lock(&sysdev_drivers_lock);
 		/* Generic notification is implicit, because it's that
 		 * code that should have called us.
@@ -253,23 +254,50 @@ int sysdev_register(struct sys_device * 
 
 		/* Notify global drivers */
 		list_for_each_entry(drv, &sysdev_drivers, entry) {
-			if (drv->add)
-				drv->add(sysdev);
+			if (drv->add) {
+				error = drv->add(sysdev);
+				if (error)
+					goto error_sysdev;
+			}
+			added_sysdev++;
 		}
 
 		/* Notify class auxillary drivers */
 		list_for_each_entry(drv, &cls->drivers, entry) {
-			if (drv->add)
-				drv->add(sysdev);
+			if (drv->add) {
+				error = drv->add(sysdev);
+				if (error)
+					goto error_cls;
+			}
+			added_cls++;
 		}
 		mutex_unlock(&sysdev_drivers_lock);
 	}
 	return error;
+
+error_cls:
+	list_for_each_entry(drv, &cls->drivers, entry) {
+		if (added_sysdev--)
+			break;
+		if (drv->add && drv->remove)
+			drv->remove(sysdev);
+	}
+error_sysdev:
+	list_for_each_entry(drv, &sysdev_drivers, entry) {
+		if (added_cls--)
+			break;
+		if (drv->add && drv->remove)
+			drv->remove(sysdev);
+	}
+	mutex_unlock(&sysdev_drivers_lock);
+	kobject_unregister(&sysdev->kobj);
+
+	return error;
 }
 
-void sysdev_unregister(struct sys_device * sysdev)
+void sysdev_unregister(struct sys_device *sysdev)
 {
-	struct sysdev_driver * drv;
+	struct sysdev_driver *drv;
 
 	mutex_lock(&sysdev_drivers_lock);
 	list_for_each_entry(drv, &sysdev_drivers, entry) {