[alsa-devel] [PATCH 2/4] sound/soc/fsl/p1022_ds.c: Add of_node_put to avoid memory leak

[Julia Lawall]

Add a call to of_node_put in the error handling code following a call to
of_parse_phandle.

This patch also moves the existing call to of_node_put tothe end of the
error handling code, to make it possible to jump to of_node_put without
doing the other cleanup operations.  These appear to be disjoint
operations, so the ordering doesn't matter.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
local idexpression x;
expression E,E1,E2;
statement S;
@@

*x = 
(of_find_node_by_path
|of_find_node_by_name
|of_find_node_by_phandle
|of_get_parent
|of_get_next_parent
|of_get_next_child
|of_find_compatible_node
|of_match_node
|of_find_node_by_type
|of_find_node_with_property
|of_find_matching_node
|of_parse_phandle
)(...);
...
if (x == NULL) S
<... when != x = E
*if (...) {
  ... when != of_node_put(x)
      when != if (...) { ... of_node_put(x); ... }
(
  return <+...x...+>;
|
*  return ...;
)
}
...>
(
E2 = x;
|
of_node_put(x);
)
// </smpl>

Signed-off-by: Julia Lawall <julia at diku.dk>

---
 sound/soc/fsl/p1022_ds.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/sound/soc/fsl/p1022_ds.c b/sound/soc/fsl/p1022_ds.c
index f8176e8..63b9eaa 100644
--- a/sound/soc/fsl/p1022_ds.c
+++ b/sound/soc/fsl/p1022_ds.c
@@ -346,8 +346,10 @@ static int p1022_ds_probe(struct platform_device *pdev)
 	}
 
 	mdata = kzalloc(sizeof(struct machine_data), GFP_KERNEL);
-	if (!mdata)
-		return -ENOMEM;
+	if (!mdata) {
+		ret = -ENOMEM;
+		goto error_put;
+	}
 
 	mdata->dai[0].cpu_dai_name = dev_name(&ssi_pdev->dev);
 	mdata->dai[0].ops = &p1022_ds_ops;
@@ -502,13 +504,12 @@ static int p1022_ds_probe(struct platform_device *pdev)
 	return 0;
 
 error:
-	of_node_put(codec_np);
-
 	if (sound_device)
 		platform_device_unregister(sound_device);
 
 	kfree(mdata);
-
+error_put:
+	of_node_put(codec_np);
 	return ret;
 }