[PATCH 3/4] GPU-DRM-TILCDC: Less function calls in tilcdc_convert_slave_node() after error detection

SF Markus Elfring
2016-09-22T08:33:29Z

Date: Thu, 22 Sep 2016 10:06:50 +0200

The of_node_put() function was called in some cases
by the tilcdc_convert_slave_node() function during error handling
even if the passed variable contained a null pointer.

* Adjust jump targets according to the Linux coding style convention.

* Split a condition check for resource detection failures so that
each pointer from these function calls will be checked immediately.

See also background information:
Topic "CWE-754: Improper check for unusual or exceptional conditions"
Link: https://cwe.mitre.org/data/definitions/754.html

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c | 28 +++++++++++++++++-----------
1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
index 6204405..6ee5865 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
@@ -209,25 +209,27 @@ void __init tilcdc_convert_slave_node(void)
return;

lcdc = of_find_matching_node(NULL, tilcdc_of_match);
- slave = of_find_matching_node(NULL, tilcdc_slave_of_match);
+ if (!of_device_is_available(lcdc))
+ goto free_table;

- if (!slave || !of_device_is_available(lcdc))
- goto out;
+ slave = of_find_matching_node(NULL, tilcdc_slave_of_match);
+ if (!slave)
+ goto put_node_lcdc;

i2c = of_parse_phandle(slave, "i2c", 0);
if (!i2c) {
pr_err("%s: Can't find i2c node trough phandle\n", __func__);
- goto out;
+ goto put_node_slave;
}

overlay = tilcdc_get_overlay(&kft);
if (!overlay)
- goto out;
+ goto put_node_i2c;

encoder = of_find_matching_node(overlay, tilcdc_tda998x_of_match);
if (!encoder) {
pr_err("%s: Failed to find tda998x node\n", __func__);
- goto out;
+ goto put_node_i2c;
}

tilcdc_copy_props(slave, encoder, tilcdc_slave_props, &kft);
@@ -238,10 +240,10 @@ void __init tilcdc_convert_slave_node(void)
continue;
if (!strncmp("i2c", (char *)prop->value, prop->length))
if (tilcdc_prop_str_update(prop, i2c->full_name, &kft))
- goto out;
+ goto put_node_fragment;
if (!strncmp("lcdc", (char *)prop->value, prop->length))
if (tilcdc_prop_str_update(prop, lcdc->full_name, &kft))
- goto out;
+ goto put_node_fragment;
}

tilcdc_node_disable(slave);
@@ -252,12 +254,16 @@ void __init tilcdc_convert_slave_node(void)
else
pr_info("%s: ti,tilcdc,slave node successfully converted\n",
__func__);
-out:
- kfree_table_free(&kft);
+ put_node_fragment:
+ of_node_put(fragment);
+ put_node_i2c:
of_node_put(i2c);
+ put_node_slave:
of_node_put(slave);
+ put_node_lcdc:
of_node_put(lcdc);
- of_node_put(fragment);
+ free_table:
+ kfree_table_free(&kft);
}

int __init tilcdc_slave_compat_init(void)
--
2.10.0