[PATCH] kobject_hotplug: permit no hotplug_ops

Make kobject_hotplug() work even if the kobject's kset doesn't implement any
hotplug_ops.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

lib/kobject_uevent.c

@@ -187,6 +187,8 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
 	u64 seq;
 	struct kobject *top_kobj = kobj;
 	struct kset *kset;
+	static struct kset_hotplug_ops null_hotplug_ops;
+	struct kset_hotplug_ops *hotplug_ops = &null_hotplug_ops;
 
 	if (!top_kobj->kset && top_kobj->parent) {
 		do {
@@ -194,15 +196,18 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
 		} while (!top_kobj->kset && top_kobj->parent);
 	}
 
-	if (top_kobj->kset && top_kobj->kset->hotplug_ops)
+	if (top_kobj->kset)
 		kset = top_kobj->kset;
 	else
 		return;
 
+	if (kset->hotplug_ops)
+		hotplug_ops = kset->hotplug_ops;
+
 	/* If the kset has a filter operation, call it.
 	   Skip the event, if the filter returns zero. */
-	if (kset->hotplug_ops->filter) {
-		if (!kset->hotplug_ops->filter(kset, kobj))
+	if (hotplug_ops->filter) {
+		if (!hotplug_ops->filter(kset, kobj))
 			return;
 	}
 
@@ -221,8 +226,8 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
 	if (!buffer)
 		goto exit;
 
-	if (kset->hotplug_ops->name)
-		name = kset->hotplug_ops->name(kset, kobj);
+	if (hotplug_ops->name)
+		name = hotplug_ops->name(kset, kobj);
 	if (name == NULL)
 		name = kset->kobj.name;
 
@@ -256,9 +261,9 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action)
 	envp [i++] = scratch;
 	scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1;
 
-	if (kset->hotplug_ops->hotplug) {
+	if (hotplug_ops->hotplug) {
 		/* have the kset specific function add its stuff */
-		retval = kset->hotplug_ops->hotplug (kset, kobj,
+		retval = hotplug_ops->hotplug (kset, kobj,
 				  &envp[i], NUM_ENVP - i, scratch,
 				  BUFFER_SIZE - (scratch - buffer));
 		if (retval) {