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From:   frowand.list@gmail.com
To:     Rob Herring <robh+dt@kernel.org>, pantelis.antoniou@konsulko.com,
        Pantelis Antoniou <panto@antoniou-consulting.com>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        geert@linux-m68k.org
Subject: [PATCH v2 2/2] of: overlay: do not include path in full_name of added nodes
Date:   Mon, 26 Feb 2018 14:01:23 -0800
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From: Frank Rowand <frank.rowand@sony.com>

Struct device_node full_name no longer includes the full path name
when the devicetree is created from a flattened device tree (FDT).
The overlay node creation code was not modified to reflect this
change.  Fix the node full_name generated by overlay code to contain
only the basename.

Unittests call an overlay internal function to create new nodes.
Fix up these calls to provide basename only instead of the full
path.

Fixes: a7e4cfb0a7ca ("of/fdt: only store the device node basename
in full_name")

Signed-off-by: Frank Rowand <frank.rowand@sony.com>
---

changes since version 1:
  - update patch one-line description and full description
  - no longer remove kbasename from resolver.c
  - add_changeset_node(): add back kbasename() when comparing nodes
    in the livetree against nodes in the overlay
  - add_changeset_node(): add header comments to document assumptions
    and behavior, and to explain why kbasename() is used

 drivers/of/dynamic.c    | 21 ++++++++++-----------
 drivers/of/of_private.h |  3 ++-
 drivers/of/overlay.c    | 18 +++++++++++++++---
 drivers/of/unittest.c   |  6 +++---
 4 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 7bb33d22b4e2..f4f8ed9b5454 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -383,25 +383,24 @@ struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags)
 
 /**
  * __of_node_dup() - Duplicate or create an empty device node dynamically.
- * @fmt: Format string (plus vargs) for new full name of the device node
+ * @np:		if not NULL, contains properties to be duplicated in new node
+ * @full_name:	string value to be duplicated into new node's full_name field
  *
- * Create an device tree node, either by duplicating an empty node or by allocating
- * an empty one suitable for further modification.  The node data are
- * dynamically allocated and all the node flags have the OF_DYNAMIC &
- * OF_DETACHED bits set. Returns the newly allocated node or NULL on out of
- * memory error.
+ * Create a device tree node, optionally duplicating the properties of
+ * another node.  The node data are dynamically allocated and all the node
+ * flags have the OF_DYNAMIC & OF_DETACHED bits set.
+ *
+ * Returns the newly allocated node or NULL on out of memory error.
  */
-struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...)
+struct device_node *__of_node_dup(const struct device_node *np,
+				  const char *full_name)
 {
-	va_list vargs;
 	struct device_node *node;
 
 	node = kzalloc(sizeof(*node), GFP_KERNEL);
 	if (!node)
 		return NULL;
-	va_start(vargs, fmt);
-	node->full_name = kvasprintf(GFP_KERNEL, fmt, vargs);
-	va_end(vargs);
+	node->full_name = kstrdup(full_name, GFP_KERNEL);
 	if (!node->full_name) {
 		kfree(node);
 		return NULL;
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 0c609e7d0334..26bb31beb03e 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -104,7 +104,8 @@ extern void *__unflatten_device_tree(const void *blob,
  * own the devtree lock or work on detached trees only.
  */
 struct property *__of_prop_dup(const struct property *prop, gfp_t allocflags);
-__printf(2, 3) struct device_node *__of_node_dup(const struct device_node *np, const char *fmt, ...);
+struct device_node *__of_node_dup(const struct device_node *np,
+				  const char *full_name);
 
 struct device_node *__of_find_node_by_path(struct device_node *parent,
 						const char *path);
diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 3397d7642958..c39df1c663be 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -307,7 +307,20 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
  * If @node has child nodes, add the children recursively via
  * build_changeset_next_level().
  *
- * NOTE: Multiple mods of created nodes not supported.
+ * NOTE_1: A live devicetree created from a flattened device tree (FDT) will
+ *       not contain the full path in node->full_name.  Thus an overlay
+ *       created from an FDT also will not contain the full path in
+ *       node->full_name.  However, a live devicetree created from Open
+ *       Firmware may have the full path in node->full_name.
+ *
+ *       add_changeset_node() follows the FDT convention and does not include
+ *       the full path in node->full_name.  Even though it expects the overlay
+ *       to not contain the full path, it uses kbasename() to remove the
+ *       full path should it exist.  It also uses kbasename() in comparisons
+ *       to nodes in the live devicetree so that it can apply an overlay to
+ *       a live devicetree created from Open Firmware.
+ *
+ * NOTE_2: 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
@@ -334,8 +347,7 @@ static int add_changeset_node(struct overlay_changeset *ovcs,
 			break;
 
 	if (!tchild) {
-		tchild = __of_node_dup(node, "%pOF/%s",
-				       target_node, node_kbasename);
+		tchild = __of_node_dup(node, node_kbasename);
 		if (!tchild)
 			return -ENOMEM;
 
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 490bbee0cf87..acf233c34ef7 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -571,13 +571,13 @@ static void __init of_unittest_changeset(void)
 	struct device_node *n1, *n2, *n21, *nchangeset, *nremove, *parent, *np;
 	struct of_changeset chgset;
 
-	n1 = __of_node_dup(NULL, "/testcase-data/changeset/n1");
+	n1 = __of_node_dup(NULL, "n1");
 	unittest(n1, "testcase setup failure\n");
 
-	n2 = __of_node_dup(NULL, "/testcase-data/changeset/n2");
+	n2 = __of_node_dup(NULL, "n2");
 	unittest(n2, "testcase setup failure\n");
 
-	n21 = __of_node_dup(NULL, "%s/%s", "/testcase-data/changeset/n2", "n21");
+	n21 = __of_node_dup(NULL, "n21");
 	unittest(n21, "testcase setup failure %p\n", n21);
 
 	nchangeset = of_find_node_by_path("/testcase-data/changeset");
-- 
Frank Rowand <frank.rowand@sony.com>