linux-kernel - [PATCH 4.4 062/113] of: fix reference counting in of_graph_get_endpoint_by

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Date:   Mon,  5 Sep 2016 18:44:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, David Jander <david@...tonic.nl>,
        Lucas Stach <l.stach@...gutronix.de>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Rob Herring <robh@...nel.org>
Subject: [PATCH 4.4 062/113] of: fix reference counting in of_graph_get_endpoint_by_regs

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lucas Stach <l.stach@...gutronix.de>

commit 34276bb062b8449b3b0a208c9b848a1a27920075 upstream.

The called of_graph_get_next_endpoint() already decrements the refcount
of the prev node, so it is wrong to do it again in the calling function.

Use the for_each_endpoint_of_node() helper to interate through the
endpoint OF nodes, which already does the right thing and simplifies
the code a bit.

Fixes: 8ccd0d0ca041
(of: add helper for getting endpoint node of specific identifiers)
Reported-by: David Jander <david@...tonic.nl>
Signed-off-by: Lucas Stach <l.stach@...gutronix.de>
Acked-by: Philipp Zabel <p.zabel@...gutronix.de>
Signed-off-by: Rob Herring <robh@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/of/base.c |   11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2253,20 +2253,13 @@ struct device_node *of_graph_get_endpoin
 	const struct device_node *parent, int port_reg, int reg)
 {
 	struct of_endpoint endpoint;
-	struct device_node *node, *prev_node = NULL;
-
-	while (1) {
-		node = of_graph_get_next_endpoint(parent, prev_node);
-		of_node_put(prev_node);
-		if (!node)
-			break;
+	struct device_node *node = NULL;
 
+	for_each_endpoint_of_node(parent, node) {
 		of_graph_parse_endpoint(node, &endpoint);
 		if (((port_reg == -1) || (endpoint.port == port_reg)) &&
 			((reg == -1) || (endpoint.id == reg)))
 			return node;
-
-		prev_node = node;
 	}
 
 	return NULL;