6 files changed, 372 insertions, 96 deletions

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
index 5f5b7ba35f1d..7a7be0515bfd 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
@@ -204,7 +204,7 @@ static void __init tilcdc_convert_slave_node(void)
 	/* For all memory needed for the overlay tree. This memory can
 	   be freed after the overlay has been applied. */
 	struct kfree_table kft;
-	int ret;
+	int ovcs_id, ret;
 
 	if (kfree_table_init(&kft))
 		return;
@@ -247,7 +247,8 @@ static void __init tilcdc_convert_slave_node(void)
 
 	tilcdc_node_disable(slave);
 
-	ret = of_overlay_apply(overlay);
+	ovcs_id = 0;
+	ret = of_overlay_apply(overlay, &ovcs_id);
 	if (ret)
 		pr_err("%s: Applying overlay changeset failed: %d\n",
 			__func__, ret);
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 4bc96af4d8e2..747d87619faf 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -491,11 +491,12 @@ static void __of_changeset_entry_invert(struct of_changeset_entry *ce,
 	}
 }
 
-static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool revert)
+static int __of_changeset_entry_notify(struct of_changeset_entry *ce,
+		bool revert)
 {
 	struct of_reconfig_data rd;
 	struct of_changeset_entry ce_inverted;
-	int ret;
+	int ret = 0;
 
 	if (revert) {
 		__of_changeset_entry_invert(ce, &ce_inverted);
@@ -517,11 +518,12 @@ static void __of_changeset_entry_notify(struct of_changeset_entry *ce, bool reve
 	default:
 		pr_err("invalid devicetree changeset action: %i\n",
 			(int)ce->action);
-		return;
+		ret = -EINVAL;
 	}
 
 	if (ret)
 		pr_err("changeset notifier error @%pOF\n", ce->np);
+	return ret;
 }
 
 static int __of_changeset_entry_apply(struct of_changeset_entry *ce)
@@ -655,32 +657,82 @@ void of_changeset_destroy(struct of_changeset *ocs)
 }
 EXPORT_SYMBOL_GPL(of_changeset_destroy);
 
-int __of_changeset_apply(struct of_changeset *ocs)
+/*
+ * Apply the changeset entries in @ocs.
+ * If apply fails, an attempt is made to revert the entries that were
+ * successfully applied.
+ *
+ * If multiple revert errors occur then only the final revert error is reported.
+ *
+ * Returns 0 on success, a negative error value in case of an error.
+ * If a revert error occurs, it is returned in *ret_revert.
+ */
+int __of_changeset_apply_entries(struct of_changeset *ocs, int *ret_revert)
 {
 	struct of_changeset_entry *ce;
-	int ret;
+	int ret, ret_tmp;
 
-	/* perform the rest of the work */
 	pr_debug("changeset: applying...\n");
 	list_for_each_entry(ce, &ocs->entries, node) {
 		ret = __of_changeset_entry_apply(ce);
 		if (ret) {
 			pr_err("Error applying changeset (%d)\n", ret);
-			list_for_each_entry_continue_reverse(ce, &ocs->entries, node)
-				__of_changeset_entry_revert(ce);
+			list_for_each_entry_continue_reverse(ce, &ocs->entries,
+							     node) {
+				ret_tmp = __of_changeset_entry_revert(ce);
+				if (ret_tmp)
+					*ret_revert = ret_tmp;
+			}
 			return ret;
 		}
 	}
-	pr_debug("changeset: applied, emitting notifiers.\n");
+
+	return 0;
+}
+
+/*
+ * Returns 0 on success, a negative error value in case of an error.
+ *
+ * If multiple changset entry notification errors occur then only the
+ * final notification error is reported.
+ */
+int __of_changeset_apply_notify(struct of_changeset *ocs)
+{
+	struct of_changeset_entry *ce;
+	int ret = 0, ret_tmp;
+
+	pr_debug("changeset: emitting notifiers.\n");
 
 	/* drop the global lock while emitting notifiers */
 	mutex_unlock(&of_mutex);
-	list_for_each_entry(ce, &ocs->entries, node)
-		__of_changeset_entry_notify(ce, 0);
+	list_for_each_entry(ce, &ocs->entries, node) {
+		ret_tmp = __of_changeset_entry_notify(ce, 0);
+		if (ret_tmp)
+			ret = ret_tmp;
+	}
 	mutex_lock(&of_mutex);
 	pr_debug("changeset: notifiers sent.\n");
 
-	return 0;
+	return ret;
+}
+
+/*
+ * Returns 0 on success, a negative error value in case of an error.
+ *
+ * If a changeset entry apply fails, an attempt is made to revert any
+ * previous entries in the changeset.  If any of the reverts fails,
+ * that failure is not reported.  Thus the state of the device tree
+ * is unknown if an apply error occurs.
+ */
+static int __of_changeset_apply(struct of_changeset *ocs)
+{
+	int ret, ret_revert = 0;
+
+	ret = __of_changeset_apply_entries(ocs, &ret_revert);
+	if (!ret)
+		ret = __of_changeset_apply_notify(ocs);
+
+	return ret;
 }
 
 /**
@@ -707,31 +759,74 @@ int of_changeset_apply(struct of_changeset *ocs)
 }
 EXPORT_SYMBOL_GPL(of_changeset_apply);
 
-int __of_changeset_revert(struct of_changeset *ocs)
+/*
+ * Revert the changeset entries in @ocs.
+ * If revert fails, an attempt is made to re-apply the entries that were
+ * successfully removed.
+ *
+ * If multiple re-apply errors occur then only the final apply error is
+ * reported.
+ *
+ * Returns 0 on success, a negative error value in case of an error.
+ * If an apply error occurs, it is returned in *ret_apply.
+ */
+int __of_changeset_revert_entries(struct of_changeset *ocs, int *ret_apply)
 {
 	struct of_changeset_entry *ce;
-	int ret;
+	int ret, ret_tmp;
 
 	pr_debug("changeset: reverting...\n");
 	list_for_each_entry_reverse(ce, &ocs->entries, node) {
 		ret = __of_changeset_entry_revert(ce);
 		if (ret) {
 			pr_err("Error reverting changeset (%d)\n", ret);
-			list_for_each_entry_continue(ce, &ocs->entries, node)
-				__of_changeset_entry_apply(ce);
+			list_for_each_entry_continue(ce, &ocs->entries, node) {
+				ret_tmp = __of_changeset_entry_apply(ce);
+				if (ret_tmp)
+					*ret_apply = ret_tmp;
+			}
 			return ret;
 		}
 	}
-	pr_debug("changeset: reverted, emitting notifiers.\n");
+
+	return 0;
+}
+
+/*
+ * If multiple changset entry notification errors occur then only the
+ * final notification error is reported.
+ */
+int __of_changeset_revert_notify(struct of_changeset *ocs)
+{
+	struct of_changeset_entry *ce;
+	int ret = 0, ret_tmp;
+
+	pr_debug("changeset: emitting notifiers.\n");
 
 	/* drop the global lock while emitting notifiers */
 	mutex_unlock(&of_mutex);
-	list_for_each_entry_reverse(ce, &ocs->entries, node)
-		__of_changeset_entry_notify(ce, 1);
+	list_for_each_entry_reverse(ce, &ocs->entries, node) {
+		ret_tmp = __of_changeset_entry_notify(ce, 1);
+		if (ret_tmp)
+			ret = ret_tmp;
+	}
 	mutex_lock(&of_mutex);
 	pr_debug("changeset: notifiers sent.\n");
 
-	return 0;
+	return ret;
+}
+
+static int __of_changeset_revert(struct of_changeset *ocs)
+{
+	int ret, ret_reply;
+
+	ret_reply = 0;
+	ret = __of_changeset_revert_entries(ocs, &ret_reply);
+
+	if (!ret)
+		ret = __of_changeset_revert_notify(ocs);
+
+	return ret;
 }
 
 /**
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 43df14f0cbce..36357f571df2 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -39,8 +39,12 @@ extern struct kset *of_kset;
 extern int of_property_notify(int action, struct device_node *np,
 			      struct property *prop, struct property *old_prop);
 extern void of_node_release(struct kobject *kobj);
-extern int __of_changeset_apply(struct of_changeset *ocs);
-extern int __of_changeset_revert(struct of_changeset *ocs);
+extern int __of_changeset_apply_entries(struct of_changeset *ocs,
+					int *ret_revert);
+extern int __of_changeset_apply_notify(struct of_changeset *ocs);
+extern int __of_changeset_revert_entries(struct of_changeset *ocs,
+					 int *ret_apply);
+extern int __of_changeset_revert_notify(struct of_changeset *ocs);
 #else /* CONFIG_OF_DYNAMIC */
 static inline int of_property_notify(int action, struct device_node *np,
 				     struct property *prop, struct property *old_prop)
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 905916e17eec..78c50fd57750 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -50,6 +50,22 @@ struct overlay_changeset {
 	struct of_changeset cset;
 };
 
+/* 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,
@@ -72,6 +88,13 @@ int of_overlay_notifier_unregister(struct notifier_block *nb)
 }
 EXPORT_SYMBOL_GPL(of_overlay_notifier_unregister);
 
+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)
 {
@@ -86,8 +109,14 @@ static int overlay_notify(struct overlay_changeset *ovcs,
 
 		ret = blocking_notifier_call_chain(&overlay_notify_chain,
 						   action, &nd);
-		if (ret)
-			return notifier_to_errno(ret);
+		if (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;
@@ -240,6 +269,14 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
  * 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.
@@ -312,8 +349,8 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
 		ret = add_changeset_property(ovcs, target_node, prop,
 					     is_symbols_node);
 		if (ret) {
-			pr_err("Failed to apply prop @%pOF/%s\n",
-			       target_node, prop->name);
+			pr_debug("Failed to apply prop @%pOF/%s, err=%d\n",
+				 target_node, prop->name, ret);
 			return ret;
 		}
 	}
@@ -324,8 +361,8 @@ static int build_changeset_next_level(struct overlay_changeset *ovcs,
 	for_each_child_of_node(overlay_node, child) {
 		ret = add_changeset_node(ovcs, target_node, child);
 		if (ret) {
-			pr_err("Failed to apply node @%pOF/%s\n",
-			       target_node, child->name);
+			pr_debug("Failed to apply node @%pOF/%s, err=%d\n",
+				 target_node, child->name, ret);
 			of_node_put(child);
 			return ret;
 		}
@@ -357,7 +394,7 @@ static int build_changeset(struct overlay_changeset *ovcs)
 					       fragment->overlay,
 					       fragment->is_symbols_node);
 		if (ret) {
-			pr_err("apply failed '%pOF'\n", fragment->target);
+			pr_debug("apply failed '%pOF'\n", fragment->target);
 			return ret;
 		}
 	}
@@ -412,6 +449,19 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs,
 	struct fragment *fragments;
 	int cnt, ret;
 
+	/*
+	 * 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__);
+
+	if (!of_node_check_flag(tree, OF_DETACHED))
+		pr_debug("%s() tree is not detached\n", __func__);
+
+	if (!of_node_is_root(tree))
+		pr_debug("%s() tree is not root\n", __func__);
+
 	INIT_LIST_HEAD(&ovcs->ovcs_list);
 
 	of_changeset_init(&ovcs->cset);
@@ -485,12 +535,13 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs,
 
 	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;
 }
 
@@ -517,33 +568,71 @@ static void free_overlay_changeset(struct overlay_changeset *ovcs)
 /**
  * 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 changeset.
  *
- * Creates and applies an overlay changeset.  If successful, the overlay
- * changeset is added to the overlay changeset list.
+ * If an error occurs in a pre-apply notifier, then no changes are made
+ * to the device tree.
  *
- * Returns the id of the created overlay changeset, or a negative error number
+
+ * 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
+ *
+ * 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_apply(struct device_node *tree)
+
+int of_overlay_apply(struct device_node *tree, int *ovcs_id)
 {
 	struct overlay_changeset *ovcs;
-	int ret;
+	int ret = 0, ret_revert, ret_tmp;
+
+	*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)
-		return -ENOMEM;
+	if (!ovcs) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
 	mutex_lock(&of_mutex);
 
 	ret = init_overlay_changeset(ovcs, tree);
-	if (ret) {
-		pr_err("init_overlay_changeset() failed, ret = %d\n", ret);
+	if (ret)
 		goto err_free_overlay_changeset;
-	}
 
 	ret = overlay_notify(ovcs, OF_OVERLAY_PRE_APPLY);
-	if (ret < 0) {
-		pr_err("%s: Pre-apply notifier failed (ret=%d)\n",
-		       __func__, ret);
+	if (ret) {
+		pr_err("overlay changeset pre-apply notify error %d\n", ret);
 		goto err_free_overlay_changeset;
 	}
 
@@ -551,23 +640,46 @@ int of_overlay_apply(struct device_node *tree)
 	if (ret)
 		goto err_free_overlay_changeset;
 
-	ret = __of_changeset_apply(&ovcs->cset);
-	if (ret)
+	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 */
+	}
 
 	list_add_tail(&ovcs->ovcs_list, &ovcs_list);
-
-	overlay_notify(ovcs, OF_OVERLAY_POST_APPLY);
+	*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;
+	}
 
 	mutex_unlock(&of_mutex);
 
-	return ovcs->id;
+	goto out;
 
 err_free_overlay_changeset:
 	free_overlay_changeset(ovcs);
 
 	mutex_unlock(&of_mutex);
 
+out:
+	pr_debug("%s() err=%d\n", __func__, ret);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(of_overlay_apply);
@@ -649,45 +761,106 @@ static int overlay_removal_is_ok(struct overlay_changeset *remove_ovcs)
 
 /**
  * of_overlay_remove() - Revert and free an overlay changeset
- * @ovcs_id:	Overlay changeset id number
+ * @ovcs_id:	Pointer to overlay changeset id
  *
- * Removes an overlay if it is permissible.  ovcs_id was previously returned
+ * 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_remove(int ovcs_id)
+int of_overlay_remove(int *ovcs_id)
 {
 	struct overlay_changeset *ovcs;
-	int ret = 0;
+	int ret, ret_apply, ret_tmp;
+
+	ret = 0;
+
+	if (devicetree_corrupt()) {
+		pr_err("suspect devicetree state, refuse to remove overlay\n");
+		ret = -EBUSY;
+		goto out;
+	}
 
 	mutex_lock(&of_mutex);
 
-	ovcs = idr_find(&ovcs_idr, ovcs_id);
+	ovcs = idr_find(&ovcs_idr, *ovcs_id);
 	if (!ovcs) {
 		ret = -ENODEV;
-		pr_err("remove: Could not find overlay #%d\n", ovcs_id);
-		goto out;
+		pr_err("remove: Could not find overlay #%d\n", *ovcs_id);
+		goto out_unlock;
 	}
 
 	if (!overlay_removal_is_ok(ovcs)) {
 		ret = -EBUSY;
-		goto out;
+		goto out_unlock;
 	}
 
-	overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
+	ret = overlay_notify(ovcs, OF_OVERLAY_PRE_REMOVE);
+	if (ret) {
+		pr_err("overlay changeset pre-remove notify error %d\n", ret);
+		goto out_unlock;
+	}
 
 	list_del(&ovcs->ovcs_list);
 
-	__of_changeset_revert(&ovcs->cset);
+	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 */
+		}
+	}
 
-	overlay_notify(ovcs, OF_OVERLAY_POST_REMOVE);
+	*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:
+out_unlock:
 	mutex_unlock(&of_mutex);
 
+out:
+	pr_debug("%s() err=%d\n", __func__, ret);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(of_overlay_remove);
@@ -706,7 +879,7 @@ int of_overlay_remove_all(void)
 
 	/* the tail of list is guaranteed to be safe to remove */
 	list_for_each_entry_safe_reverse(ovcs, ovcs_n, &ovcs_list, ovcs_list) {
-		ret = of_overlay_remove(ovcs->id);
+		ret = of_overlay_remove(&ovcs->id);
 		if (ret)
 			return ret;
 	}
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index bbdaf5606820..3640dae4b9b2 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1217,7 +1217,7 @@ static void of_unittest_untrack_overlay(int id)
 
 static void of_unittest_destroy_tracked_overlays(void)
 {
-	int id, ret, defers;
+	int id, ret, defers, ovcs_id;
 
 	if (overlay_first_id < 0)
 		return;
@@ -1230,7 +1230,8 @@ static void of_unittest_destroy_tracked_overlays(void)
 			if (!(overlay_id_bits[BIT_WORD(id)] & BIT_MASK(id)))
 				continue;
 
-			ret = of_overlay_remove(id + overlay_first_id);
+			ovcs_id = id + overlay_first_id;
+			ret = of_overlay_remove(&ovcs_id);
 			if (ret == -ENODEV) {
 				pr_warn("%s: no overlay to destroy for #%d\n",
 					__func__, id + overlay_first_id);
@@ -1252,7 +1253,7 @@ static int of_unittest_apply_overlay(int overlay_nr, int unittest_nr,
 		int *overlay_id)
 {
 	struct device_node *np = NULL;
-	int ret, id = -1;
+	int ret;
 
 	np = of_find_node_by_path(overlay_path(overlay_nr));
 	if (np == NULL) {
@@ -1262,23 +1263,20 @@ static int of_unittest_apply_overlay(int overlay_nr, int unittest_nr,
 		goto out;
 	}
 
-	ret = of_overlay_apply(np);
+	*overlay_id = 0;
+	ret = of_overlay_apply(np, overlay_id);
 	if (ret < 0) {
 		unittest(0, "could not create overlay from \"%s\"\n",
 				overlay_path(overlay_nr));
 		goto out;
 	}
-	id = ret;
-	of_unittest_track_overlay(id);
+	of_unittest_track_overlay(*overlay_id);
 
 	ret = 0;
 
 out:
 	of_node_put(np);
 
-	if (overlay_id)
-		*overlay_id = id;
-
 	return ret;
 }
 
@@ -1286,7 +1284,7 @@ out:
 static int of_unittest_apply_overlay_check(int overlay_nr, int unittest_nr,
 		int before, int after, enum overlay_type ovtype)
 {
-	int ret;
+	int ret, ovcs_id;
 
 	/* unittest device must not be in before state */
 	if (of_unittest_device_exists(unittest_nr, ovtype) != before) {
@@ -1297,7 +1295,8 @@ static int of_unittest_apply_overlay_check(int overlay_nr, int unittest_nr,
 		return -EINVAL;
 	}
 
-	ret = of_unittest_apply_overlay(overlay_nr, unittest_nr, NULL);
+	ovcs_id = 0;
+	ret = of_unittest_apply_overlay(overlay_nr, unittest_nr, &ovcs_id);
 	if (ret != 0) {
 		/* of_unittest_apply_overlay already called unittest() */
 		return ret;
@@ -1320,7 +1319,7 @@ static int of_unittest_apply_revert_overlay_check(int overlay_nr,
 		int unittest_nr, int before, int after,
 		enum overlay_type ovtype)
 {
-	int ret, ov_id;
+	int ret, ovcs_id;
 
 	/* unittest device must be in before state */
 	if (of_unittest_device_exists(unittest_nr, ovtype) != before) {
@@ -1332,7 +1331,8 @@ static int of_unittest_apply_revert_overlay_check(int overlay_nr,
 	}
 
 	/* apply the overlay */
-	ret = of_unittest_apply_overlay(overlay_nr, unittest_nr, &ov_id);
+	ovcs_id = 0;
+	ret = of_unittest_apply_overlay(overlay_nr, unittest_nr, &ovcs_id);
 	if (ret != 0) {
 		/* of_unittest_apply_overlay already called unittest() */
 		return ret;
@@ -1347,7 +1347,7 @@ static int of_unittest_apply_revert_overlay_check(int overlay_nr,
 		return -EINVAL;
 	}
 
-	ret = of_overlay_remove(ov_id);
+	ret = of_overlay_remove(&ovcs_id);
 	if (ret != 0) {
 		unittest(0, "overlay @\"%s\" failed to be destroyed @\"%s\"\n",
 				overlay_path(overlay_nr),
@@ -1449,7 +1449,7 @@ static void of_unittest_overlay_5(void)
 static void of_unittest_overlay_6(void)
 {
 	struct device_node *np;
-	int ret, i, ov_id[2];
+	int ret, i, ov_id[2], ovcs_id;
 	int overlay_nr = 6, unittest_nr = 6;
 	int before = 0, after = 1;
 
@@ -1476,13 +1476,14 @@ static void of_unittest_overlay_6(void)
 			return;
 		}
 
-		ret = of_overlay_apply(np);
+		ovcs_id = 0;
+		ret = of_overlay_apply(np, &ovcs_id);
 		if (ret < 0)  {
 			unittest(0, "could not create overlay from \"%s\"\n",
 					overlay_path(overlay_nr + i));
 			return;
 		}
-		ov_id[i] = ret;
+		ov_id[i] = ovcs_id;
 		of_unittest_track_overlay(ov_id[i]);
 	}
 
@@ -1500,7 +1501,8 @@ static void of_unittest_overlay_6(void)
 	}
 
 	for (i = 1; i >= 0; i--) {
-		ret = of_overlay_remove(ov_id[i]);
+		ovcs_id = ov_id[i];
+		ret = of_overlay_remove(&ovcs_id);
 		if (ret != 0) {
 			unittest(0, "overlay @\"%s\" failed destroy @\"%s\"\n",
 					overlay_path(overlay_nr + i),
@@ -1531,7 +1533,7 @@ static void of_unittest_overlay_6(void)
 static void of_unittest_overlay_8(void)
 {
 	struct device_node *np;
-	int ret, i, ov_id[2];
+	int ret, i, ov_id[2], ovcs_id;
 	int overlay_nr = 8, unittest_nr = 8;
 
 	/* we don't care about device state in this test */
@@ -1546,18 +1548,20 @@ static void of_unittest_overlay_8(void)
 			return;
 		}
 
-		ret = of_overlay_apply(np);
+		ovcs_id = 0;
+		ret = of_overlay_apply(np, &ovcs_id);
 		if (ret < 0)  {
 			unittest(0, "could not create overlay from \"%s\"\n",
 					overlay_path(overlay_nr + i));
 			return;
 		}
-		ov_id[i] = ret;
+		ov_id[i] = ovcs_id;
 		of_unittest_track_overlay(ov_id[i]);
 	}
 
 	/* now try to remove first overlay (it should fail) */
-	ret = of_overlay_remove(ov_id[0]);
+	ovcs_id = ov_id[0];
+	ret = of_overlay_remove(&ovcs_id);
 	if (ret == 0) {
 		unittest(0, "overlay @\"%s\" was destroyed @\"%s\"\n",
 				overlay_path(overlay_nr + 0),
@@ -1568,7 +1572,8 @@ static void of_unittest_overlay_8(void)
 
 	/* removing them in order should work */
 	for (i = 1; i >= 0; i--) {
-		ret = of_overlay_remove(ov_id[i]);
+		ovcs_id = ov_id[i];
+		ret = of_overlay_remove(&ovcs_id);
 		if (ret != 0) {
 			unittest(0, "overlay @\"%s\" not destroyed @\"%s\"\n",
 					overlay_path(overlay_nr + i),
@@ -2149,13 +2154,11 @@ static int __init overlay_data_add(int onum)
 		goto out_free_np_overlay;
 	}
 
-	ret = of_overlay_apply(info->np_overlay);
+	info->overlay_id = 0;
+	ret = of_overlay_apply(info->np_overlay, &info->overlay_id);
 	if (ret < 0) {
 		pr_err("of_overlay_apply() (ret=%d), %d\n", ret, onum);
 		goto out_free_np_overlay;
-	} else {
-		info->overlay_id = ret;
-		ret = 0;
 	}
 
 	pr_debug("__dtb_overlay_begin applied, overlay id %d\n", ret);
diff --git a/include/linux/of.h b/include/linux/of.h
index 7569e9cc45de..96edda95c6b0 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1298,7 +1298,7 @@ static inline bool of_device_is_system_power_controller(const struct device_node
  */
 
 enum of_overlay_notify_action {
-	OF_OVERLAY_PRE_APPLY,
+	OF_OVERLAY_PRE_APPLY = 0,
 	OF_OVERLAY_POST_APPLY,
 	OF_OVERLAY_PRE_REMOVE,
 	OF_OVERLAY_POST_REMOVE,
@@ -1312,8 +1312,8 @@ struct of_overlay_notify_data {
 #ifdef CONFIG_OF_OVERLAY
 
 /* ID based overlays; the API for external users */
-int of_overlay_apply(struct device_node *tree);
-int of_overlay_remove(int id);
+int of_overlay_apply(struct device_node *tree, int *ovcs_id);
+int of_overlay_remove(int *ovcs_id);
 int of_overlay_remove_all(void);
 
 int of_overlay_notifier_register(struct notifier_block *nb);
@@ -1321,12 +1321,12 @@ int of_overlay_notifier_unregister(struct notifier_block *nb);
 
 #else
 
-static inline int of_overlay_apply(struct device_node *tree)
+static inline int of_overlay_apply(struct device_node *tree, int *ovcs_id)
 {
 	return -ENOTSUPP;
 }
 
-static inline int of_overlay_remove(int id)
+static inline int of_overlay_remove(int *ovcs_id)
 {
 	return -ENOTSUPP;
 }