1 files changed, 116 insertions, 55 deletions

diff --git a/drivers/base/attribute_container.c b/drivers/base/attribute_container.c
index ecc1929d7f6a..b6f941a6ab69 100644
--- a/drivers/base/attribute_container.c
+++ b/drivers/base/attribute_container.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * attribute_container.c - implementation of a simple container for classes
  *
  * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
  *
- * This file is licensed under GPLv2
- *
  * The basic idea here is to enable a device to be attached to an
  * aritrary numer of classes without having to allocate storage for them.
  * Instead, the contained classes select the devices they need to attach
@@ -12,7 +11,6 @@
  */
 
 #include <linux/attribute_container.h>
-#include <linux/init.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
@@ -75,9 +73,9 @@ int
 attribute_container_register(struct attribute_container *cont)
 {
 	INIT_LIST_HEAD(&cont->node);
-	klist_init(&cont->containers,internal_container_klist_get,
+	klist_init(&cont->containers, internal_container_klist_get,
 		   internal_container_klist_put);
-		
+
 	mutex_lock(&attribute_container_mutex);
 	list_add_tail(&cont->node, &attribute_container_list);
 	mutex_unlock(&attribute_container_mutex);
@@ -95,6 +93,7 @@ int
 attribute_container_unregister(struct attribute_container *cont)
 {
 	int retval = -EBUSY;
+
 	mutex_lock(&attribute_container_mutex);
 	spin_lock(&cont->containers.k_lock);
 	if (!list_empty(&cont->containers.k_list))
@@ -105,14 +104,14 @@ attribute_container_unregister(struct attribute_container *cont)
 	spin_unlock(&cont->containers.k_lock);
 	mutex_unlock(&attribute_container_mutex);
 	return retval;
-		
+
 }
 EXPORT_SYMBOL_GPL(attribute_container_unregister);
 
 /* private function used as class release */
 static void attribute_container_release(struct device *classdev)
 {
-	struct internal_container *ic 
+	struct internal_container *ic
 		= container_of(classdev, struct internal_container, classdev);
 	struct device *dev = classdev->parent;
 
@@ -185,8 +184,8 @@ attribute_container_add_device(struct device *dev,
 		struct klist_node *n = klist_next(iter); \
 		n ? container_of(n, typeof(*pos), member) : \
 			({ klist_iter_exit(iter) ; NULL; }); \
-	}) ) != NULL; )
-			
+	})) != NULL;)
+
 
 /**
  * attribute_container_remove_device - make device eligible for removal.
@@ -237,68 +236,143 @@ attribute_container_remove_device(struct device *dev,
 	mutex_unlock(&attribute_container_mutex);
 }
 
+static int
+do_attribute_container_device_trigger_safe(struct device *dev,
+					   struct attribute_container *cont,
+					   int (*fn)(struct attribute_container *,
+						     struct device *, struct device *),
+					   int (*undo)(struct attribute_container *,
+						       struct device *, struct device *))
+{
+	int ret;
+	struct internal_container *ic, *failed;
+	struct klist_iter iter;
+
+	if (attribute_container_no_classdevs(cont))
+		return fn(cont, dev, NULL);
+
+	klist_for_each_entry(ic, &cont->containers, node, &iter) {
+		if (dev == ic->classdev.parent) {
+			ret = fn(cont, dev, &ic->classdev);
+			if (ret) {
+				failed = ic;
+				klist_iter_exit(&iter);
+				goto fail;
+			}
+		}
+	}
+	return 0;
+
+fail:
+	if (!undo)
+		return ret;
+
+	/* Attempt to undo the work partially done. */
+	klist_for_each_entry(ic, &cont->containers, node, &iter) {
+		if (ic == failed) {
+			klist_iter_exit(&iter);
+			break;
+		}
+		if (dev == ic->classdev.parent)
+			undo(cont, dev, &ic->classdev);
+	}
+	return ret;
+}
+
 /**
- * attribute_container_device_trigger - execute a trigger for each matching classdev
+ * attribute_container_device_trigger_safe - execute a trigger for each
+ * matching classdev or fail all of them.
  *
  * @dev:  The generic device to run the trigger for
- * @fn	  the function to execute for each classdev.
+ * @fn:   the function to execute for each classdev.
+ * @undo: A function to undo the work previously done in case of error
  *
- * This funcion is for executing a trigger when you need to know both
- * the container and the classdev.  If you only care about the
- * container, then use attribute_container_trigger() instead.
+ * This function is a safe version of
+ * attribute_container_device_trigger. It stops on the first error and
+ * undo the partial work that has been done, on previous classdev.  It
+ * is guaranteed that either they all succeeded, or none of them
+ * succeeded.
  */
-void
-attribute_container_device_trigger(struct device *dev, 
-				   int (*fn)(struct attribute_container *,
-					     struct device *,
-					     struct device *))
+int
+attribute_container_device_trigger_safe(struct device *dev,
+					int (*fn)(struct attribute_container *,
+						  struct device *,
+						  struct device *),
+					int (*undo)(struct attribute_container *,
+						    struct device *,
+						    struct device *))
 {
-	struct attribute_container *cont;
+	struct attribute_container *cont, *failed = NULL;
+	int ret = 0;
 
 	mutex_lock(&attribute_container_mutex);
+
 	list_for_each_entry(cont, &attribute_container_list, node) {
-		struct internal_container *ic;
-		struct klist_iter iter;
 
 		if (!cont->match(cont, dev))
 			continue;
 
-		if (attribute_container_no_classdevs(cont)) {
-			fn(cont, dev, NULL);
-			continue;
+		ret = do_attribute_container_device_trigger_safe(dev, cont,
+								 fn, undo);
+		if (ret) {
+			failed = cont;
+			break;
 		}
+	}
 
-		klist_for_each_entry(ic, &cont->containers, node, &iter) {
-			if (dev == ic->classdev.parent)
-				fn(cont, dev, &ic->classdev);
+	if (ret && !WARN_ON(!undo)) {
+		list_for_each_entry(cont, &attribute_container_list, node) {
+
+			if (failed == cont)
+				break;
+
+			if (!cont->match(cont, dev))
+				continue;
+
+			do_attribute_container_device_trigger_safe(dev, cont,
+								   undo, NULL);
 		}
 	}
+
 	mutex_unlock(&attribute_container_mutex);
+	return ret;
+
 }
 
 /**
- * attribute_container_trigger - trigger a function for each matching container
+ * attribute_container_device_trigger - execute a trigger for each matching classdev
  *
- * @dev:  The generic device to activate the trigger for
- * @fn:	  the function to trigger
+ * @dev:  The generic device to run the trigger for
+ * @fn:   the function to execute for each classdev.
  *
- * This routine triggers a function that only needs to know the
- * matching containers (not the classdev) associated with a device.
- * It is more lightweight than attribute_container_device_trigger, so
- * should be used in preference unless the triggering function
- * actually needs to know the classdev.
+ * This function is for executing a trigger when you need to know both
+ * the container and the classdev.
  */
 void
-attribute_container_trigger(struct device *dev,
-			    int (*fn)(struct attribute_container *,
-				      struct device *))
+attribute_container_device_trigger(struct device *dev,
+				   int (*fn)(struct attribute_container *,
+					     struct device *,
+					     struct device *))
 {
 	struct attribute_container *cont;
 
 	mutex_lock(&attribute_container_mutex);
 	list_for_each_entry(cont, &attribute_container_list, node) {
-		if (cont->match(cont, dev))
-			fn(cont, dev);
+		struct internal_container *ic;
+		struct klist_iter iter;
+
+		if (!cont->match(cont, dev))
+			continue;
+
+		if (attribute_container_no_classdevs(cont)) {
+			fn(cont, dev, NULL);
+			continue;
+		}
+
+		klist_for_each_entry(ic, &cont->containers, node, &iter) {
+			if (dev == ic->classdev.parent)
+				fn(cont, dev, &ic->classdev);
+		}
 	}
 	mutex_unlock(&attribute_container_mutex);
 }
@@ -350,26 +424,13 @@ int
 attribute_container_add_class_device(struct device *classdev)
 {
 	int error = device_add(classdev);
+
 	if (error)
 		return error;
 	return attribute_container_add_attrs(classdev);
 }
 
 /**
- * attribute_container_add_class_device_adapter - simple adapter for triggers
- *
- * This function is identical to attribute_container_add_class_device except
- * that it is designed to be called from the triggers
- */
-int
-attribute_container_add_class_device_adapter(struct attribute_container *cont,
-					     struct device *dev,
-					     struct device *classdev)
-{
-	return attribute_container_add_class_device(classdev);
-}
-
-/**
  * attribute_container_remove_attrs - remove any attribute files
  *
  * @classdev: The class device to remove the files from