linux-kernel - [PATCH] of/address: Fix of_node memory leak in of_dma_is

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Date:   Tue, 10 Nov 2020 15:28:25 +1300
From:   Evan Nimmo <evan.nimmo@...iedtelesis.co.nz>
To:     frowand.list@...il.com, robh+dt@...nel.org
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Evan Nimmo <evan.nimmo@...iedtelesis.co.nz>
Subject: [PATCH] of/address: Fix of_node memory leak in of_dma_is_coherent

Commit dabf6b36b83a ("of: Add OF_DMA_DEFAULT_COHERENT & select it on
powerpc") added a check to of_dma_is_coherent which returns early
if OF_DMA_DEFAULT_COHERENT is enabled. This results in the of_node_put()
being skipped causing a memory leak. Moved the of_node_get() below this
check so we now we only get the node if OF_DMA_DEFAULT_COHERENT is not
enabled.

Fixes: dabf6b36b83a ("of: Add OF_DMA_DEFAULT_COHERENT & select it on
powerpc")

Signed-off-by: Evan Nimmo <evan.nimmo@...iedtelesis.co.nz>
---
 drivers/of/address.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index eb9ab4f1e80b..1c3257a2d4e3 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -1034,11 +1034,13 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
  */
 bool of_dma_is_coherent(struct device_node *np)
 {
-	struct device_node *node = of_node_get(np);
+	struct device_node *node;
 
 	if (IS_ENABLED(CONFIG_OF_DMA_DEFAULT_COHERENT))
 		return true;
 
+	node = of_node_get(np);
+
 	while (node) {
 		if (of_property_read_bool(node, "dma-coherent")) {
 			of_node_put(node);
-- 
2.27.0