[PATCH] thermal: tegra: delete unneeded of_node_put

Julia Lawall
2017-07-15T08:42:32Z

Device node iterators perform an of_node_put on each iteration, so putting
an of_node_put before a continue results in a double put.

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

// <smpl>
@@
expression e1;
local idexpression child;
iterator name for_each_child_of_node;
@@

for_each_child_of_node(e1,child) {
... when != of_node_get(child)
* of_node_put(child);
...
* continue;
}
// </smpl>

Furthermore, the call to thermal_of_cooling_device_register immediately
calls __thermal_cooling_device_register with the same arguments. The
latter function stores the device node argument, which is the second
argument of for_each_child_of_node, in the returned thermal_cooling_device
structure. This returned structure is then stored in the cdev field of
stc. Thus it seems that the second argument of for_each_child_of_node
escapes the scope of the for_each_child_of_node, so an explicit of_node_get
on success of thermal_of_cooling_device_register is also needed.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

---
drivers/thermal/tegra/soctherm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
index 7d2db23..10f4fdd 100644
--- a/drivers/thermal/tegra/soctherm.c
+++ b/drivers/thermal/tegra/soctherm.c
@@ -1014,7 +1014,6 @@ static void soctherm_init_hw_throt_cdev(struct platform_device *pdev)
tcd = thermal_of_cooling_device_register(np_stcc,
(char *)name, ts,
&throt_cooling_ops);
- of_node_put(np_stcc);
if (IS_ERR_OR_NULL(tcd)) {
dev_err(dev,
"throttle-cfg: %s: failed to register cooling device\n",
@@ -1022,6 +1021,7 @@ static void soctherm_init_hw_throt_cdev(struct platform_device *pdev)
continue;
}

+ of_node_get(np_stcc);
stc->cdev = tcd;
stc->init = true;
}