Merge tag 'devicetree-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

Pull DeviceTree updates from Rob Herring:
 "A bigger diffstat than usual with the kbuild changes and a tree wide
  fix in the binding documentation.

  Summary:

   - kbuild cleanups and improvements for dtbs

   - Code clean-up of overlay code and fixing for some long standing
     memory leak and race condition in applying overlays

   - Improvements to DT memory usage making sysfs/kobjects optional and
     skipping unflattening of disabled nodes. This is part of kernel
     tinification efforts.

   - Final piece of removing storing the full path for every DT node.
     The prerequisite conversion of printk's to use device_node format
     specifier happened in 4.14.

   - Sync with current upstream dtc. This brings additional checks to
     dtb compiling.

   - Binding doc tree wide removal of leading 0s from examples

   - RTC binding documentation adding missing devices and some
     consolidation of duplicated bindings

   - Vendor prefix documentation for nutsboard, Silicon Storage
     Technology, shimafuji, Tecon Microprocessor Technologies, DH
     electronics GmbH, Opal Kelly, and Next Thing"

* tag 'devicetree-for-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (55 commits)
  dt-bindings: usb: add #phy-cells to usb-nop-xceiv
  dt-bindings: Remove leading zeros from bindings notation
  kbuild: handle dtb-y and CONFIG_OF_ALL_DTBS natively in Makefile.lib
  MIPS: dts: remove bogus bcm96358nb4ser.dtb from dtb-y entry
  kbuild: clean up *.dtb and *.dtb.S patterns from top-level Makefile
  .gitignore: move *.dtb and *.dtb.S patterns to the top-level .gitignore
  .gitignore: sort normal pattern rules alphabetically
  dt-bindings: add vendor prefix for Next Thing Co.
  scripts/dtc: Update to upstream version v1.4.5-6-gc1e55a5513e9
  of: dynamic: fix memory leak related to properties of __of_node_dup
  of: overlay: make pr_err() string unique
  of: overlay: pr_err from return NOTIFY_OK to overlay apply/remove
  of: overlay: remove unneeded check for NULL kbasename()
  of: overlay: remove a dependency on device node full_name
  of: overlay: simplify applying symbols from an overlay
  of: overlay: avoid race condition between applying multiple overlays
  of: overlay: loosen overly strict phandle clash check
  of: overlay: expand check of whether overlay changeset can be removed
  of: overlay: detect cases where device tree may become corrupt
  of: overlay: minor restructuring
  ...

1 files changed, 672 insertions, 377 deletions

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 8ecfee31ab6d..c150abb9049d 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -25,252 +25,378 @@
 #include "of_private.h"
 
 /**
- * struct of_overlay_info - Holds a single overlay info
+ * struct fragment - info about fragment nodes in overlay expanded device tree
  * @target:	target of the overlay operation
- * @overlay:	pointer to the overlay contents node
- *
- * Holds a single overlay state, including all the overlay logs &
- * records.
+ * @overlay:	pointer to the __overlay__ node
  */
-struct of_overlay_info {
+struct fragment {
 	struct device_node *target;
 	struct device_node *overlay;
-	bool is_symbols_node;
 };
 
 /**
- * struct of_overlay - Holds a complete overlay transaction
- * @node:	List on which we are located
- * @count:	Count of ovinfo structures
- * @ovinfo_tab:	Overlay info table (count sized)
- * @cset:	Changeset to be used
- *
- * Holds a complete overlay transaction
+ * struct overlay_changeset
+ * @ovcs_list:		list on which we are located
+ * @overlay_tree:	expanded device tree that contains the fragment nodes
+ * @count:		count of fragment structures
+ * @fragments:		fragment nodes in the overlay expanded device tree
+ * @symbols_fragment:	last element of @fragments[] is the  __symbols__ node
+ * @cset:		changeset to apply fragments to live device tree
  */
-struct of_overlay {
+struct overlay_changeset {
 	int id;
-	struct list_head node;
+	struct list_head ovcs_list;
+	struct device_node *overlay_tree;
 	int count;
-	struct of_overlay_info *ovinfo_tab;
+	struct fragment *fragments;
+	bool symbols_fragment;
 	struct of_changeset cset;
 };
 
-static int of_overlay_apply_one(struct of_overlay *ov,
-		struct device_node *target, const struct device_node *overlay,
-		bool is_symbols_node);
+/* flags are sticky - once set, do not reset */
+static int devicetree_state_flags;
+#define DTSF_APPLY_FAIL		0x01
+#define DTSF_REVERT_FAIL	0x02
+
+/*
+ * If a changeset apply or revert encounters an error, an attempt will
+ * be made to undo partial changes, but may fail.  If the undo fails
+ * we do not know the state of the devicetree.
+ */
+static int devicetree_corrupt(void)
+{
+	return devicetree_state_flags &
+		(DTSF_APPLY_FAIL | DTSF_REVERT_FAIL);
+}
+
+static int build_changeset_next_level(struct overlay_changeset *ovcs,
+		struct device_node *target_node,
+		const struct device_node *overlay_node);
+
+/*
+ * of_resolve_phandles() finds the largest phandle in the live tree.
+ * of_overlay_apply() may add a larger phandle to the live tree.
+ * Do not allow race between two overlays being applied simultaneously:
+ *    mutex_lock(&of_overlay_phandle_mutex)
+ *    of_resolve_phandles()
+ *    of_overlay_apply()
+ *    mutex_unlock(&of_overlay_phandle_mutex)
+ */
+static DEFINE_MUTEX(of_overlay_phandle_mutex);
+
+void of_overlay_mutex_lock(void)
+{
+	mutex_lock(&of_overlay_phandle_mutex);
+}
+
+void of_overlay_mutex_unlock(void)
+{
+	mutex_unlock(&of_overlay_phandle_mutex);
+}
 
-static BLOCKING_NOTIFIER_HEAD(of_overlay_chain);
+
+static LIST_HEAD(ovcs_list);
+static DEFINE_IDR(ovcs_idr);
+
+static BLOCKING_NOTIFIER_HEAD(overlay_notify_chain);
 
 int of_overlay_notifier_register(struct notifier_block *nb)
 {
-	return blocking_notifier_chain_register(&of_overlay_chain, nb);
+	return blocking_notifier_chain_register(&overlay_notify_chain, nb);
 }
 EXPORT_SYMBOL_GPL(of_overlay_notifier_register);
 
 int of_overlay_notifier_unregister(struct notifier_block *nb)
 {
-	return blocking_notifier_chain_unregister(&of_overlay_chain, nb);
+	return blocking_notifier_chain_unregister(&overlay_notify_chain, nb);
 }
 EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
 
-static int of_overlay_notify(struct of_overlay *ov,
-			     enum of_overlay_notify_action action)
+static char *of_overlay_action_name[] = {
+	"pre-apply",
+	"post-apply",
+	"pre-remove",
+	"post-remove",
+};
+
+static int overlay_notify(struct overlay_changeset *ovcs,
+		enum of_overlay_notify_action action)
 {
 	struct of_overlay_notify_data nd;
 	int i, ret;
 
-	for (i = 0; i < ov->count; i++) {
-		struct of_overlay_info *ovinfo = &ov->ovinfo_tab[i];
+	for (i = 0; i < ovcs->count; i++) {
+		struct fragment *fragment = &ovcs->fragments[i];
 
-		nd.target = ovinfo->target;
-		nd.overlay = ovinfo->overlay;
+		nd.target = fragment->target;
+		nd.overlay = fragment->overlay;
 
-		ret = blocking_notifier_call_chain(&of_overlay_chain,
+		ret = blocking_notifier_call_chain(&overlay_notify_chain,
 						   action, &nd);
-		if (ret)
-			return notifier_to_errno(ret);
+		if (ret == NOTIFY_OK || ret == NOTIFY_STOP)
+			return 0;
+		if (ret) {
+			ret = notifier_to_errno(ret);
+			pr_err("overlay changeset %s notifier error %d, target: %pOF\n",
+			       of_overlay_action_name[action], ret, nd.target);
+			return ret;
+		}
 	}
 
 	return 0;
 }
 
-static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
-		const struct property *prop)
+/*
+ * The values of properties in the "/__symbols__" node are paths in
+ * the ovcs->overlay_tree.  When duplicating the properties, the paths
+ * need to be adjusted to be the correct path for the live device tree.
+ *
+ * The paths refer to a node in the subtree of a fragment node's "__overlay__"
+ * node, for example "/fragment@0/__overlay__/symbol_path_tail",
+ * where symbol_path_tail can be a single node or it may be a multi-node path.
+ *
+ * The duplicated property value will be modified by replacing the
+ * "/fragment_name/__overlay/" portion of the value  with the target
+ * path from the fragment node.
+ */
+static struct property *dup_and_fixup_symbol_prop(
+		struct overlay_changeset *ovcs, const struct property *prop)
 {
-	struct of_overlay_info *ovinfo;
-	struct property *new;
-	const char *overlay_name;
-	char *label_path;
-	char *symbol_path;
+	struct fragment *fragment;
+	struct property *new_prop;
+	struct device_node *fragment_node;
+	struct device_node *overlay_node;
+	const char *path;
+	const char *path_tail;
 	const char *target_path;
 	int k;
-	int label_path_len;
 	int overlay_name_len;
+	int path_len;
+	int path_tail_len;
 	int target_path_len;
 
 	if (!prop->value)
 		return NULL;
-	symbol_path = prop->value;
-
-	new = kzalloc(sizeof(*new), GFP_KERNEL);
-	if (!new)
+	if (strnlen(prop->value, prop->length) >= prop->length)
 		return NULL;
+	path = prop->value;
+	path_len = strlen(path);
 
-	for (k = 0; k < ov->count; k++) {
-		ovinfo = &ov->ovinfo_tab[k];
-		overlay_name = ovinfo->overlay->full_name;
-		overlay_name_len = strlen(overlay_name);
-		if (!strncasecmp(symbol_path, overlay_name, overlay_name_len))
+	if (path_len < 1)
+		return NULL;
+	fragment_node = __of_find_node_by_path(ovcs->overlay_tree, path + 1);
+	overlay_node = __of_find_node_by_path(fragment_node, "__overlay__/");
+	of_node_put(fragment_node);
+	of_node_put(overlay_node);
+
+	for (k = 0; k < ovcs->count; k++) {
+		fragment = &ovcs->fragments[k];
+		if (fragment->overlay == overlay_node)
 			break;
 	}
+	if (k >= ovcs->count)
+		return NULL;
+
+	overlay_name_len = snprintf(NULL, 0, "%pOF", fragment->overlay);
 
-	if (k >= ov->count)
-		goto err_free;
+	if (overlay_name_len > path_len)
+		return NULL;
+	path_tail = path + overlay_name_len;
+	path_tail_len = strlen(path_tail);
 
-	target_path = ovinfo->target->full_name;
+	target_path = kasprintf(GFP_KERNEL, "%pOF", fragment->target);
+	if (!target_path)
+		return NULL;
 	target_path_len = strlen(target_path);
 
-	label_path = symbol_path + overlay_name_len;
-	label_path_len = strlen(label_path);
+	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
+	if (!new_prop)
+		goto err_free_target_path;
 
-	new->name = kstrdup(prop->name, GFP_KERNEL);
-	new->length = target_path_len + label_path_len + 1;
-	new->value = kzalloc(new->length, GFP_KERNEL);
+	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
+	new_prop->length = target_path_len + path_tail_len + 1;
+	new_prop->value = kzalloc(new_prop->length, GFP_KERNEL);
+	if (!new_prop->name || !new_prop->value)
+		goto err_free_new_prop;
 
-	if (!new->name || !new->value)
-		goto err_free;
+	strcpy(new_prop->value, target_path);
+	strcpy(new_prop->value + target_path_len, path_tail);
 
-	strcpy(new->value, target_path);
-	strcpy(new->value + target_path_len, label_path);
+	of_property_set_flag(new_prop, OF_DYNAMIC);
 
-	/* mark the property as dynamic */
-	of_property_set_flag(new, OF_DYNAMIC);
+	return new_prop;
 
-	return new;
+err_free_new_prop:
+	kfree(new_prop->name);
+	kfree(new_prop->value);
+	kfree(new_prop);
+err_free_target_path:
+	kfree(target_path);
 
- err_free:
-	kfree(new->name);
-	kfree(new->value);
-	kfree(new);
 	return NULL;
-
-
 }
 
-static int of_overlay_apply_single_property(struct of_overlay *ov,
-		struct device_node *target, struct property *prop,
-		bool is_symbols_node)
+/**
+ * add_changeset_property() - add @overlay_prop to overlay changeset
+ * @ovcs:		overlay changeset
+ * @target_node:	where to place @overlay_prop in live tree
+ * @overlay_prop:	property to add or update, from overlay tree
+ * @is_symbols_prop:	1 if @overlay_prop is from node "/__symbols__"
+ *
+ * If @overlay_prop does not already exist in @target_node, add changeset entry
+ * to add @overlay_prop in @target_node, else add changeset entry to update
+ * value of @overlay_prop.
+ *
+ * Some special properties are not updated (no error returned).
+ *
+ * Update of property in symbols node is not allowed.
+ *
+ * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
+ * invalid @overlay.
+ */
+static int add_changeset_property(struct overlay_changeset *ovcs,
+		struct device_node *target_node,
+		struct property *overlay_prop,
+		bool is_symbols_prop)
 {
-	struct property *propn = NULL, *tprop;
+	struct property *new_prop = NULL, *prop;
+	int ret = 0;
 
-	/* NOTE: Multiple changes of single properties not supported */
-	tprop = of_find_property(target, prop->name, NULL);
+	prop = of_find_property(target_node, overlay_prop->name, NULL);
 
-	/* special properties are not meant to be updated (silent NOP) */
-	if (of_prop_cmp(prop->name, "name") == 0 ||
-	    of_prop_cmp(prop->name, "phandle") == 0 ||
-	    of_prop_cmp(prop->name, "linux,phandle") == 0)
+	if (!of_prop_cmp(overlay_prop->name, "name") ||
+	    !of_prop_cmp(overlay_prop->name, "phandle") ||
+	    !of_prop_cmp(overlay_prop->name, "linux,phandle"))
 		return 0;
 
-	if (is_symbols_node) {
-		/* changing a property in __symbols__ node not allowed */
-		if (tprop)
+	if (is_symbols_prop) {
+		if (prop)
 			return -EINVAL;
-		propn = dup_and_fixup_symbol_prop(ov, prop);
+		new_prop = dup_and_fixup_symbol_prop(ovcs, overlay_prop);
 	} else {
-		propn = __of_prop_dup(prop, GFP_KERNEL);
+		new_prop = __of_prop_dup(overlay_prop, GFP_KERNEL);
 	}
 
-	if (propn == NULL)
+	if (!new_prop)
 		return -ENOMEM;
 
-	/* not found? add */
-	if (tprop == NULL)
-		return of_changeset_add_property(&ov->cset, target, propn);
-
-	/* found? update */
-	return of_changeset_update_property(&ov->cset, target, propn);
+	if (!prop)
+		ret = of_changeset_add_property(&ovcs->cset, target_node,
+						new_prop);
+	else
+		ret = of_changeset_update_property(&ovcs->cset, target_node,
+						   new_prop);
+
+	if (ret) {
+		kfree(new_prop->name);
+		kfree(new_prop->value);
+		kfree(new_prop);
+	}
+	return ret;
 }
 
-static int of_overlay_apply_single_device_node(struct of_overlay *ov,
-		struct device_node *target, struct device_node *child)
+/**
+ * add_changeset_node() - add @node (and children) to overlay changeset
+ * @ovcs:		overlay changeset
+ * @target_node:	where to place @node in live tree
+ * @node:		node from within overlay device tree fragment
+ *
+ * If @node does not already exist in @target_node, add changeset entry
+ * to add @node in @target_node.
+ *
+ * If @node already exists in @target_node, and the existing node has
+ * a phandle, the overlay node is not allowed to have a phandle.
+ *
+ * If @node has child nodes, add the children recursively via
+ * build_changeset_next_level().
+ *
+ * NOTE: Multiple mods of created nodes not supported.
+ *       If more than one fragment contains a node that does not already exist
+ *       in the live tree, then for each fragment of_changeset_attach_node()
+ *       will add a changeset entry to add the node.  When the changeset is
+ *       applied, __of_attach_node() will attach the node twice (once for
+ *       each fragment).  At this point the device tree will be corrupted.
+ *
+ *       TODO: add integrity check to ensure that multiple fragments do not
+ *             create the same node.
+ *
+ * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
+ * invalid @overlay.
+ */
+static int add_changeset_node(struct overlay_changeset *ovcs,
+		struct device_node *target_node, struct device_node *node)
 {
-	const char *cname;
+	const char *node_kbasename;
 	struct device_node *tchild;
 	int ret = 0;
 
-	cname = kbasename(child->full_name);
-	if (cname == NULL)
-		return -ENOMEM;
+	node_kbasename = kbasename(node->full_name);
 
-	/* NOTE: Multiple mods of created nodes not supported */
-	for_each_child_of_node(target, tchild)
-		if (!of_node_cmp(cname, kbasename(tchild->full_name)))
+	for_each_child_of_node(target_node, tchild)
+		if (!of_node_cmp(node_kbasename, kbasename(tchild->full_name)))
 			break;
 
-	if (tchild != NULL) {
-		/* new overlay phandle value conflicts with existing value */
-		if (child->phandle)
-			return -EINVAL;
-
-		/* apply overlay recursively */
-		ret = of_overlay_apply_one(ov, tchild, child, 0);
-		of_node_put(tchild);
-	} else {
-		/* create empty tree as a target */
-		tchild = __of_node_dup(child, "%pOF/%s", target, cname);
+	if (!tchild) {
+		tchild = __of_node_dup(node, "%pOF/%s",
+				       target_node, node_kbasename);
 		if (!tchild)
 			return -ENOMEM;
 
-		/* point to parent */
-		tchild->parent = target;
+		tchild->parent = target_node;
 
-		ret = of_changeset_attach_node(&ov->cset, tchild);
+		ret = of_changeset_attach_node(&ovcs->cset, tchild);
 		if (ret)
 			return ret;
 
-		ret = of_overlay_apply_one(ov, tchild, child, 0);
-		if (ret)
-			return ret;
+		return build_changeset_next_level(ovcs, tchild, node);
 	}
 
+	if (node->phandle && tchild->phandle)
+		ret = -EINVAL;
+	else
+		ret = build_changeset_next_level(ovcs, tchild, node);
+	of_node_put(tchild);
+
 	return ret;
 }
 
-/*
- * Apply a single overlay node recursively.
+/**
+ * build_changeset_next_level() - add level of overlay changeset
+ * @ovcs:		overlay changeset
+ * @target_node:	where to place @overlay_node in live tree
+ * @overlay_node:	node from within an overlay device tree fragment
+ *
+ * Add the properties (if any) and nodes (if any) from @overlay_node to the
+ * @ovcs->cset changeset.  If an added node has child nodes, they will
+ * be added recursively.
  *
- * Note that the in case of an error the target node is left
- * in a inconsistent state. Error recovery should be performed
- * by using the changeset.
+ * Do not allow symbols node to have any children.
+ *
+ * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
+ * invalid @overlay_node.
  */
-static int of_overlay_apply_one(struct of_overlay *ov,
-		struct device_node *target, const struct device_node *overlay,
-		bool is_symbols_node)
+static int build_changeset_next_level(struct overlay_changeset *ovcs,
+		struct device_node *target_node,
+		const struct device_node *overlay_node)
 {
 	struct device_node *child;
 	struct property *prop;
 	int ret;
 
-	for_each_property_of_node(overlay, prop) {
-		ret = of_overlay_apply_single_property(ov, target, prop,
-						       is_symbols_node);
+	for_each_property_of_node(overlay_node, prop) {
+		ret = add_changeset_property(ovcs, target_node, prop, 0);
 		if (ret) {
-			pr_err("Failed to apply prop @%pOF/%s\n",
-			       target, prop->name);
+			pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
+				 target_node, prop->name, ret);
 			return ret;
 		}
 	}
 
-	/* do not allow symbols node to have any children */
-	if (is_symbols_node)
-		return 0;
-
-	for_each_child_of_node(overlay, child) {
-		ret = of_overlay_apply_single_device_node(ov, target, child);
-		if (ret != 0) {
-			pr_err("Failed to apply single node @%pOF/%s\n",
-			       target, child->name);
+	for_each_child_of_node(overlay_node, child) {
+		ret = add_changeset_node(ovcs, target_node, child);
+		if (ret) {
+			pr_debug("Failed to apply node @%pOF/%s, err=%d\n",
+				 target_node, child->name, ret);
 			of_node_put(child);
 			return ret;
 		}
@@ -279,28 +405,72 @@ static int of_overlay_apply_one(struct of_overlay *ov,
 	return 0;
 }
 
+/*
+ * Add the properties from __overlay__ node to the @ovcs->cset changeset.
+ */
+static int build_changeset_symbols_node(struct overlay_changeset *ovcs,
+		struct device_node *target_node,
+		const struct device_node *overlay_symbols_node)
+{
+	struct property *prop;
+	int ret;
+
+	for_each_property_of_node(overlay_symbols_node, prop) {
+		ret = add_changeset_property(ovcs, target_node, prop, 1);
+		if (ret) {
+			pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
+				 target_node, prop->name, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
 /**
- * of_overlay_apply() - Apply @count overlays pointed at by @ovinfo_tab
- * @ov:		Overlay to apply
+ * build_changeset() - populate overlay changeset in @ovcs from @ovcs->fragments
+ * @ovcs:	Overlay changeset
  *
- * Applies the overlays given, while handling all error conditions
- * appropriately. Either the operation succeeds, or if it fails the
- * live tree is reverted to the state before the attempt.
- * Returns 0, or an error if the overlay attempt failed.
+ * Create changeset @ovcs->cset to contain the nodes and properties of the
+ * overlay device tree fragments in @ovcs->fragments[].  If an error occurs,
+ * any portions of the changeset that were successfully created will remain
+ * in @ovcs->cset.
+ *
+ * Returns 0 on success, -ENOMEM if memory allocation failure, or -EINVAL if
+ * invalid overlay in @ovcs->fragments[].
  */
-static int of_overlay_apply(struct of_overlay *ov)
+static int build_changeset(struct overlay_changeset *ovcs)
 {
-	int i, err;
-
-	/* first we apply the overlays atomically */
-	for (i = 0; i < ov->count; i++) {
-		struct of_overlay_info *ovinfo = &ov->ovinfo_tab[i];
+	struct fragment *fragment;
+	int fragments_count, i, ret;
+
+	/*
+	 * if there is a symbols fragment in ovcs->fragments[i] it is
+	 * the final element in the array
+	 */
+	if (ovcs->symbols_fragment)
+		fragments_count = ovcs->count - 1;
+	else
+		fragments_count = ovcs->count;
+
+	for (i = 0; i < fragments_count; i++) {
+		fragment = &ovcs->fragments[i];
+
+		ret = build_changeset_next_level(ovcs, fragment->target,
+						 fragment->overlay);
+		if (ret) {
+			pr_debug("apply failed '%pOF'\n", fragment->target);
+			return ret;
+		}
+	}
 
-		err = of_overlay_apply_one(ov, ovinfo->target, ovinfo->overlay,
-					   ovinfo->is_symbols_node);
-		if (err != 0) {
-			pr_err("apply failed '%pOF'\n", ovinfo->target);
-			return err;
+	if (ovcs->symbols_fragment) {
+		fragment = &ovcs->fragments[ovcs->count - 1];
+		ret = build_changeset_symbols_node(ovcs, fragment->target,
+						   fragment->overlay);
+		if (ret) {
+			pr_debug("apply failed '%pOF'\n", fragment->target);
+			return ret;
 		}
 	}
 
@@ -309,10 +479,10 @@ static int of_overlay_apply(struct of_overlay *ov)
 
 /*
  * Find the target node using a number of different strategies
- * in order of preference
+ * in order of preference:
  *
- * "target" property containing the phandle of the target
- * "target-path" property containing the path of the target
+ * 1) "target" property containing the phandle of the target
+ * 2) "target-path" property containing the path of the target
  */
 static struct device_node *find_target_node(struct device_node *info_node)
 {
@@ -320,14 +490,12 @@ static struct device_node *find_target_node(struct device_node *info_node)
 	u32 val;
 	int ret;
 
-	/* first try to go by using the target as a phandle */
 	ret = of_property_read_u32(info_node, "target", &val);
-	if (ret == 0)
+	if (!ret)
 		return of_find_node_by_phandle(val);
 
-	/* now try to locate by path */
 	ret = of_property_read_string(info_node, "target-path", &path);
-	if (ret == 0)
+	if (!ret)
 		return of_find_node_by_path(path);
 
 	pr_err("Failed to find target for node %p (%s)\n",
@@ -337,228 +505,290 @@ static struct device_node *find_target_node(struct device_node *info_node)
 }
 
 /**
- * of_fill_overlay_info() - Fill an overlay info structure
- * @ov		Overlay to fill
- * @info_node:	Device node containing the overlay
- * @ovinfo:	Pointer to the overlay info structure to fill
- *
- * Fills an overlay info structure with the overlay information
- * from a device node. This device node must have a target property
- * which contains a phandle of the overlay target node, and an
- * __overlay__ child node which has the overlay contents.
- * Both ovinfo->target & ovinfo->overlay have their references taken.
- *
- * Returns 0 on success, or a negative error value.
+ * init_overlay_changeset() - initialize overlay changeset from overlay tree
+ * @ovcs	Overlay changeset to build
+ * @tree:	Contains all the overlay fragments and overlay fixup nodes
+ *
+ * Initialize @ovcs.  Populate @ovcs->fragments with node information from
+ * the top level of @tree.  The relevant top level nodes are the fragment
+ * nodes and the __symbols__ node.  Any other top level node will be ignored.
+ *
+ * Returns 0 on success, -ENOMEM if memory allocation failure, -EINVAL if error
+ * detected in @tree, or -ENOSPC if idr_alloc() error.
  */
-static int of_fill_overlay_info(struct of_overlay *ov,
-		struct device_node *info_node, struct of_overlay_info *ovinfo)
+static int init_overlay_changeset(struct overlay_changeset *ovcs,
+		struct device_node *tree)
 {
-	ovinfo->overlay = of_get_child_by_name(info_node, "__overlay__");
-	if (ovinfo->overlay == NULL)
-		goto err_fail;
+	struct device_node *node, *overlay_node;
+	struct fragment *fragment;
+	struct fragment *fragments;
+	int cnt, ret;
 
-	ovinfo->target = find_target_node(info_node);
-	if (ovinfo->target == NULL)
-		goto err_fail;
+	/*
+	 * Warn for some issues.  Can not return -EINVAL for these until
+	 * of_unittest_apply_overlay() is fixed to pass these checks.
+	 */
+	if (!of_node_check_flag(tree, OF_DYNAMIC))
+		pr_debug("%s() tree is not dynamic\n", __func__);
 
-	return 0;
+	if (!of_node_check_flag(tree, OF_DETACHED))
+		pr_debug("%s() tree is not detached\n", __func__);
 
-err_fail:
-	of_node_put(ovinfo->target);
-	of_node_put(ovinfo->overlay);
+	if (!of_node_is_root(tree))
+		pr_debug("%s() tree is not root\n", __func__);
 
-	memset(ovinfo, 0, sizeof(*ovinfo));
-	return -EINVAL;
-}
+	ovcs->overlay_tree = tree;
 
-/**
- * of_build_overlay_info() - Build an overlay info array
- * @ov		Overlay to build
- * @tree:	Device node containing all the overlays
- *
- * Helper function that given a tree containing overlay information,
- * allocates and builds an overlay info array containing it, ready
- * for use using of_overlay_apply.
- *
- * Returns 0 on success with the @cntp @ovinfop pointers valid,
- * while on error a negative error value is returned.
- */
-static int of_build_overlay_info(struct of_overlay *ov,
-		struct device_node *tree)
-{
-	struct device_node *node;
-	struct of_overlay_info *ovinfo;
-	int cnt, err;
+	INIT_LIST_HEAD(&ovcs->ovcs_list);
+
+	of_changeset_init(&ovcs->cset);
+
+	ovcs->id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL);
+	if (ovcs->id <= 0)
+		return ovcs->id;
 
-	/* worst case; every child is a node */
 	cnt = 0;
-	for_each_child_of_node(tree, node)
-		cnt++;
 
-	if (of_get_child_by_name(tree, "__symbols__"))
+	/* fragment nodes */
+	for_each_child_of_node(tree, node) {
+		overlay_node = of_get_child_by_name(node, "__overlay__");
+		if (overlay_node) {
+			cnt++;
+			of_node_put(overlay_node);
+		}
+	}
+
+	node = of_get_child_by_name(tree, "__symbols__");
+	if (node) {
 		cnt++;
+		of_node_put(node);
+	}
 
-	ovinfo = kcalloc(cnt, sizeof(*ovinfo), GFP_KERNEL);
-	if (ovinfo == NULL)
-		return -ENOMEM;
+	fragments = kcalloc(cnt, sizeof(*fragments), GFP_KERNEL);
+	if (!fragments) {
+		ret = -ENOMEM;
+		goto err_free_idr;
+	}
 
 	cnt = 0;
 	for_each_child_of_node(tree, node) {
-		err = of_fill_overlay_info(ov, node, &ovinfo[cnt]);
-		if (err == 0)
-			cnt++;
+		fragment = &fragments[cnt];
+		fragment->overlay = of_get_child_by_name(node, "__overlay__");
+		if (fragment->overlay) {
+			fragment->target = find_target_node(node);
+			if (!fragment->target) {
+				of_node_put(fragment->overlay);
+				ret = -EINVAL;
+				goto err_free_fragments;
+			} else {
+				cnt++;
+			}
+		}
 	}
 
+	/*
+	 * if there is a symbols fragment in ovcs->fragments[i] it is
+	 * the final element in the array
+	 */
 	node = of_get_child_by_name(tree, "__symbols__");
 	if (node) {
-		ovinfo[cnt].overlay = node;
-		ovinfo[cnt].target = of_find_node_by_path("/__symbols__");
-		ovinfo[cnt].is_symbols_node = 1;
-
-		if (!ovinfo[cnt].target) {
-			pr_err("no symbols in root of device tree.\n");
-			return -EINVAL;
+		ovcs->symbols_fragment = 1;
+		fragment = &fragments[cnt];
+		fragment->overlay = node;
+		fragment->target = of_find_node_by_path("/__symbols__");
+
+		if (!fragment->target) {
+			pr_err("symbols in overlay, but not in live tree\n");
+			ret = -EINVAL;
+			goto err_free_fragments;
 		}
 
 		cnt++;
 	}
 
-	/* if nothing filled, return error */
-	if (cnt == 0) {
-		kfree(ovinfo);
-		return -ENODEV;
+	if (!cnt) {
+		ret = -EINVAL;
+		goto err_free_fragments;
 	}
 
-	ov->count = cnt;
-	ov->ovinfo_tab = ovinfo;
+	ovcs->count = cnt;
+	ovcs->fragments = fragments;
 
 	return 0;
+
+err_free_fragments:
+	kfree(fragments);
+err_free_idr:
+	idr_remove(&ovcs_idr, ovcs->id);
+
+	pr_err("%s() failed, ret = %d\n", __func__, ret);
+
+	return ret;
 }
 
-/**
- * of_free_overlay_info() - Free an overlay info array
- * @ov		Overlay to free the overlay info from
- * @ovinfo_tab:	Array of overlay_info's to free
- *
- * Releases the memory of a previously allocated ovinfo array
- * by of_build_overlay_info.
- * Returns 0, or an error if the arguments are bogus.
- */
-static int of_free_overlay_info(struct of_overlay *ov)
+static void free_overlay_changeset(struct overlay_changeset *ovcs)
 {
-	struct of_overlay_info *ovinfo;
 	int i;
 
-	/* do it in reverse */
-	for (i = ov->count - 1; i >= 0; i--) {
-		ovinfo = &ov->ovinfo_tab[i];
+	if (!ovcs->cset.entries.next)
+		return;
+	of_changeset_destroy(&ovcs->cset);
+
+	if (ovcs->id)
+		idr_remove(&ovcs_idr, ovcs->id);
 
-		of_node_put(ovinfo->target);
-		of_node_put(ovinfo->overlay);
+	for (i = 0; i < ovcs->count; i++) {
+		of_node_put(ovcs->fragments[i].target);
+		of_node_put(ovcs->fragments[i].overlay);
 	}
-	kfree(ov->ovinfo_tab);
+	kfree(ovcs->fragments);
 
-	return 0;
+	kfree(ovcs);
 }
 
-static LIST_HEAD(ov_list);
-static DEFINE_IDR(ov_idr);
-
 /**
- * of_overlay_create() - Create and apply an overlay
- * @tree:	Device node containing all the overlays
+ * of_overlay_apply() - Create and apply an overlay changeset
+ * @tree:	Expanded overlay device tree
+ * @ovcs_id:	Pointer to overlay changeset id
  *
- * Creates and applies an overlay while also keeping track
- * of the overlay in a list. This list can be used to prevent
- * illegal overlay removals.
+ * Creates and applies an overlay changeset.
+ *
+ * If an error occurs in a pre-apply notifier, then no changes are made
+ * to the device tree.
+ *
+
+ * A non-zero return value will not have created the changeset if error is from:
+ *   - parameter checks
+ *   - building the changeset
+ *   - overlay changset pre-apply notifier
  *
- * Returns the id of the created overlay, or a negative error number
+ * If an error is returned by an overlay changeset pre-apply notifier
+ * then no further overlay changeset pre-apply notifier will be called.
+ *
+ * A non-zero return value will have created the changeset if error is from:
+ *   - overlay changeset entry notifier
+ *   - overlay changset post-apply notifier
+ *
+ * If an error is returned by an overlay changeset post-apply notifier
+ * then no further overlay changeset post-apply notifier will be called.
+ *
+ * If more than one notifier returns an error, then the last notifier
+ * error to occur is returned.
+ *
+ * If an error occurred while applying the overlay changeset, then an
+ * attempt is made to revert any changes that were made to the
+ * device tree.  If there were any errors during the revert attempt
+ * then the state of the device tree can not be determined, and any
+ * following attempt to apply or remove an overlay changeset will be
+ * refused.
+ *
+ * Returns 0 on success, or a negative error number.  Overlay changeset
+ * id is returned to *ovcs_id.
  */
-int of_overlay_create(struct device_node *tree)
+
+int of_overlay_apply(struct device_node *tree, int *ovcs_id)
 {
-	struct of_overlay *ov;
-	int err, id;
+	struct overlay_changeset *ovcs;
+	int ret = 0, ret_revert, ret_tmp;
 
-	/* allocate the overlay structure */
-	ov = kzalloc(sizeof(*ov), GFP_KERNEL);
-	if (ov == NULL)
-		return -ENOMEM;
-	ov->id = -1;
+	*ovcs_id = 0;
+
+	if (devicetree_corrupt()) {
+		pr_err("devicetree state suspect, refuse to apply overlay\n");
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ovcs = kzalloc(sizeof(*ovcs), GFP_KERNEL);
+	if (!ovcs) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
-	INIT_LIST_HEAD(&ov->node);
+	of_overlay_mutex_lock();
 
-	of_changeset_init(&ov->cset);
+	ret = of_resolve_phandles(tree);
+	if (ret)
+		goto err_overlay_unlock;
 
 	mutex_lock(&of_mutex);
 
-	id = idr_alloc(&ov_idr, ov, 0, 0, GFP_KERNEL);
-	if (id < 0) {
-		err = id;
-		goto err_destroy_trans;
-	}
-	ov->id = id;
+	ret = init_overlay_changeset(ovcs, tree);
+	if (ret)
+		goto err_free_overlay_changeset;
 
-	/* build the overlay info structures */
-	err = of_build_overlay_info(ov, tree);
-	if (err) {
-		pr_err("of_build_overlay_info() failed for tree@%pOF\n",
-		       tree);
-		goto err_free_idr;
+	ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY);
+	if (ret) {
+		pr_err("overlay changeset pre-apply notify error %d\n", ret);
+		goto err_free_overlay_changeset;
 	}
 
-	err = of_overlay_notify(ov, OF_OVERLAY_PRE_APPLY);
-	if (err < 0) {
-		pr_err("%s: Pre-apply notifier failed (err=%d)\n",
-		       __func__, err);
-		goto err_free_idr;
+	ret = build_changeset(ovcs);
+	if (ret)
+		goto err_free_overlay_changeset;
+
+	ret_revert = 0;
+	ret = __of_changeset_apply_entries(&ovcs->cset, &ret_revert);
+	if (ret) {
+		if (ret_revert) {
+			pr_debug("overlay changeset revert error %d\n",
+				 ret_revert);
+			devicetree_state_flags |= DTSF_APPLY_FAIL;
+		}
+		goto err_free_overlay_changeset;
+	} else {
+		ret = __of_changeset_apply_notify(&ovcs->cset);
+		if (ret)
+			pr_err("overlay changeset entry notify error %d\n",
+			       ret);
+		/* fall through */
 	}
 
-	/* apply the overlay */
-	err = of_overlay_apply(ov);
-	if (err)
-		goto err_abort_trans;
-
-	/* apply the changeset */
-	err = __of_changeset_apply(&ov->cset);
-	if (err)
-		goto err_revert_overlay;
+	list_add_tail(&ovcs->ovcs_list, &ovcs_list);
+	*ovcs_id = ovcs->id;
 
+	ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_APPLY);
+	if (ret_tmp) {
+		pr_err("overlay changeset post-apply notify error %d\n",
+		       ret_tmp);
+		if (!ret)
+			ret = ret_tmp;
+	}
 
-	/* add to the tail of the overlay list */
-	list_add_tail(&ov->node, &ov_list);
+	mutex_unlock(&of_mutex);
+	of_overlay_mutex_unlock();
 
-	of_overlay_notify(ov, OF_OVERLAY_POST_APPLY);
+	goto out;
 
-	mutex_unlock(&of_mutex);
+err_overlay_unlock:
+	of_overlay_mutex_unlock();
 
-	return id;
+err_free_overlay_changeset:
+	free_overlay_changeset(ovcs);
 
-err_revert_overlay:
-err_abort_trans:
-	of_free_overlay_info(ov);
-err_free_idr:
-	idr_remove(&ov_idr, ov->id);
-err_destroy_trans:
-	of_changeset_destroy(&ov->cset);
-	kfree(ov);
 	mutex_unlock(&of_mutex);
 
-	return err;
+out:
+	pr_debug("%s() err=%d\n", __func__, ret);
+
+	return ret;
 }
-EXPORT_SYMBOL_GPL(of_overlay_create);
+EXPORT_SYMBOL_GPL(of_overlay_apply);
 
-/* check whether the given node, lies under the given tree */
-static int overlay_subtree_check(struct device_node *tree,
-		struct device_node *dn)
+/*
+ * Find @np in @tree.
+ *
+ * Returns 1 if @np is @tree or is contained in @tree, else 0
+ */
+static int find_node(struct device_node *tree, struct device_node *np)
 {
 	struct device_node *child;
 
-	/* match? */
-	if (tree == dn)
+	if (tree == np)
 		return 1;
 
 	for_each_child_of_node(tree, child) {
-		if (overlay_subtree_check(child, dn)) {
+		if (find_node(child, np)) {
 			of_node_put(child);
 			return 1;
 		}
@@ -567,29 +797,39 @@ static int overlay_subtree_check(struct device_node *tree,
 	return 0;
 }
 
-/* check whether this overlay is the topmost */
-static int overlay_is_topmost(struct of_overlay *ov, struct device_node *dn)
+/*
+ * Is @remove_ce_node a child of, a parent of, or the same as any
+ * node in an overlay changeset more topmost than @remove_ovcs?
+ *
+ * Returns 1 if found, else 0
+ */
+static int node_overlaps_later_cs(struct overlay_changeset *remove_ovcs,
+		struct device_node *remove_ce_node)
 {
-	struct of_overlay *ovt;
+	struct overlay_changeset *ovcs;
 	struct of_changeset_entry *ce;
 
-	list_for_each_entry_reverse(ovt, &ov_list, node) {
-		/* if we hit ourselves, we're done */
-		if (ovt == ov)
+	list_for_each_entry_reverse(ovcs, &ovcs_list, ovcs_list) {
+		if (ovcs == remove_ovcs)
 			break;
 
-		/* check against each subtree affected by this overlay */
-		list_for_each_entry(ce, &ovt->cset.entries, node) {
-			if (overlay_subtree_check(ce->np, dn)) {
-				pr_err("%s: #%d clashes #%d @%pOF\n",
-					__func__, ov->id, ovt->id, dn);
-				return 0;
+		list_for_each_entry(ce, &ovcs->cset.entries, node) {
+			if (find_node(ce->np, remove_ce_node)) {
+				pr_err("%s: #%d overlaps with #%d @%pOF\n",
+					__func__, remove_ovcs->id, ovcs->id,
+					remove_ce_node);
+				return 1;
+			}
+			if (find_node(remove_ce_node, ce->np)) {
+				pr_err("%s: #%d overlaps with #%d @%pOF\n",
+					__func__, remove_ovcs->id, ovcs->id,
+					remove_ce_node);
+				return 1;
 			}
 		}
 	}
 
-	/* overlay is topmost */
-	return 1;
+	return 0;
 }
 
 /*
@@ -602,13 +842,13 @@ static int overlay_is_topmost(struct of_overlay *ov, struct device_node *dn)
  * the one closest to the tail. If another overlay has affected this
  * device node and is closest to the tail, then removal is not permited.
  */
-static int overlay_removal_is_ok(struct of_overlay *ov)
+static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs)
 {
-	struct of_changeset_entry *ce;
+	struct of_changeset_entry *remove_ce;
 
-	list_for_each_entry(ce, &ov->cset.entries, node) {
-		if (!overlay_is_topmost(ov, ce->np)) {
-			pr_err("overlay #%d is not topmost\n", ov->id);
+	list_for_each_entry(remove_ce, &remove_ovcs->cset.entries, node) {
+		if (node_overlaps_later_cs(remove_ovcs, remove_ce->np)) {
+			pr_err("overlay #%d is not topmost\n", remove_ovcs->id);
 			return 0;
 		}
 	}
@@ -617,75 +857,130 @@ static int overlay_removal_is_ok(struct of_overlay *ov)
 }
 
 /**
- * of_overlay_destroy() - Removes an overlay
- * @id:	Overlay id number returned by a previous call to of_overlay_create
+ * of_overlay_remove() - Revert and free an overlay changeset
+ * @ovcs_id:	Pointer to overlay changeset id
  *
- * Removes an overlay if it is permissible.
+ * Removes an overlay if it is permissible.  @ovcs_id was previously returned
+ * by of_overlay_apply().
  *
- * Returns 0 on success, or a negative error number
+ * If an error occurred while attempting to revert the overlay changeset,
+ * then an attempt is made to re-apply any changeset entry that was
+ * reverted.  If an error occurs on re-apply then the state of the device
+ * tree can not be determined, and any following attempt to apply or remove
+ * an overlay changeset will be refused.
+ *
+ * A non-zero return value will not revert the changeset if error is from:
+ *   - parameter checks
+ *   - overlay changset pre-remove notifier
+ *   - overlay changeset entry revert
+ *
+ * If an error is returned by an overlay changeset pre-remove notifier
+ * then no further overlay changeset pre-remove notifier will be called.
+ *
+ * If more than one notifier returns an error, then the last notifier
+ * error to occur is returned.
+ *
+ * A non-zero return value will revert the changeset if error is from:
+ *   - overlay changeset entry notifier
+ *   - overlay changset post-remove notifier
+ *
+ * If an error is returned by an overlay changeset post-remove notifier
+ * then no further overlay changeset post-remove notifier will be called.
+ *
+ * Returns 0 on success, or a negative error number.  *ovcs_id is set to
+ * zero after reverting the changeset, even if a subsequent error occurs.
  */
-int of_overlay_destroy(int id)
+int of_overlay_remove(int *ovcs_id)
 {
-	struct of_overlay *ov;
-	int err;
+	struct overlay_changeset *ovcs;
+	int ret, ret_apply, ret_tmp;
 
-	mutex_lock(&of_mutex);
+	ret = 0;
 
-	ov = idr_find(&ov_idr, id);
-	if (ov == NULL) {
-		err = -ENODEV;
-		pr_err("destroy: Could not find overlay #%d\n", id);
+	if (devicetree_corrupt()) {
+		pr_err("suspect devicetree state, refuse to remove overlay\n");
+		ret = -EBUSY;
 		goto out;
 	}
 
-	/* check whether the overlay is safe to remove */
-	if (!overlay_removal_is_ok(ov)) {
-		err = -EBUSY;
-		goto out;
+	mutex_lock(&of_mutex);
+
+	ovcs = idr_find(&ovcs_idr, *ovcs_id);
+	if (!ovcs) {
+		ret = -ENODEV;
+		pr_err("remove: Could not find overlay #%d\n", *ovcs_id);
+		goto out_unlock;
 	}
 
-	of_overlay_notify(ov, OF_OVERLAY_PRE_REMOVE);
-	list_del(&ov->node);
-	__of_changeset_revert(&ov->cset);
-	of_overlay_notify(ov, OF_OVERLAY_POST_REMOVE);
-	of_free_overlay_info(ov);
-	idr_remove(&ov_idr, id);
-	of_changeset_destroy(&ov->cset);
-	kfree(ov);
+	if (!overlay_removal_is_ok(ovcs)) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
 
-	err = 0;
+	ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
+	if (ret) {
+		pr_err("overlay changeset pre-remove notify error %d\n", ret);
+		goto out_unlock;
+	}
 
-out:
+	list_del(&ovcs->ovcs_list);
+
+	ret_apply = 0;
+	ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply);
+	if (ret) {
+		if (ret_apply)
+			devicetree_state_flags |= DTSF_REVERT_FAIL;
+		goto out_unlock;
+	} else {
+		ret = __of_changeset_revert_notify(&ovcs->cset);
+		if (ret) {
+			pr_err("overlay changeset entry notify error %d\n",
+			       ret);
+			/* fall through - changeset was reverted */
+		}
+	}
+
+	*ovcs_id = 0;
+
+	ret_tmp = overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE);
+	if (ret_tmp) {
+		pr_err("overlay changeset post-remove notify error %d\n",
+		       ret_tmp);
+		if (!ret)
+			ret = ret_tmp;
+	}
+
+	free_overlay_changeset(ovcs);
+
+out_unlock:
 	mutex_unlock(&of_mutex);
 
-	return err;
+out:
+	pr_debug("%s() err=%d\n", __func__, ret);
+
+	return ret;
 }
-EXPORT_SYMBOL_GPL(of_overlay_destroy);
+EXPORT_SYMBOL_GPL(of_overlay_remove);
 
 /**
- * of_overlay_destroy_all() - Removes all overlays from the system
+ * of_overlay_remove_all() - Reverts and frees all overlay changesets
  *
  * Removes all overlays from the system in the correct order.
  *
  * Returns 0 on success, or a negative error number
  */
-int of_overlay_destroy_all(void)
+int of_overlay_remove_all(void)
 {
-	struct of_overlay *ov, *ovn;
-
-	mutex_lock(&of_mutex);
+	struct overlay_changeset *ovcs, *ovcs_n;
+	int ret;
 
 	/* the tail of list is guaranteed to be safe to remove */
-	list_for_each_entry_safe_reverse(ov, ovn, &ov_list, node) {
-		list_del(&ov->node);
-		__of_changeset_revert(&ov->cset);
-		of_free_overlay_info(ov);
-		idr_remove(&ov_idr, ov->id);
-		kfree(ov);
+	list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) {
+		ret = of_overlay_remove(&ovcs->id);
+		if (ret)
+			return ret;
 	}
 
-	mutex_unlock(&of_mutex);
-
 	return 0;
 }
-EXPORT_SYMBOL_GPL(of_overlay_destroy_all);
+EXPORT_SYMBOL_GPL(of_overlay_remove_all);