Re: [PATCH 2/2] arch/powerpc/platforms/powermac/setup.c: add missing of_node_put

On Mon, 22 Aug 2011, walter harms wrote:

Am 21.08.2011 18:10, schrieb Julia Lawall:

quoted

From: Julia Lawall <redacted>

np is initialized to the result of calling a function that calls
of_node_get, so of_node_put should be called before the pointer is dropped.

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

// <smpl>
@@
expression e,e1,e2;
@@

* e = \(of_find_node_by_type\|of_find_node_by_name\)(...)
  ... when != of_node_put(e)
      when != true e == NULL
      when != e2 = e
  e = e1
// </smpl>

Signed-off-by: Julia Lawall <redacted>

---
 arch/powerpc/platforms/powermac/setup.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 96580b1..970ea1d 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c

@@ -494,11 +494,15 @@ static int __init pmac_declare_of_platform_devices(void)
 		return -1;
 
 	np = of_find_node_by_name(NULL, "valkyrie");
-	if (np)
+	if (np) {
 		of_platform_device_create(np, "valkyrie", NULL);
+		of_node_put(np);
+	}
 	np = of_find_node_by_name(NULL, "platinum");
-	if (np)
+	if (np) {
 		of_platform_device_create(np, "platinum", NULL);
+		of_node_put(np);
+	}
         np = of_find_node_by_type(NULL, "smu");
         if (np) {
 		of_platform_device_create(np, "smu", NULL);

hi,
it seems save to call of_node_put(np) with np==NULL, i assume the same is true
for of_platform_device_create().

so the code collapses to:

_test_node(char *name)
{
 struct device_node *np;
 np = of_find_node_by_name(NULL, name);
 of_platform_device_create(np, name, NULL);
 of_node_put(np);
 return NULL?:0:1;
}

maybe there is already something like find_node() ?

of_platform_device_create is not much used, and one might want to use it 
with other functions than of_find_node_by_name, as indeed is done here.  
Is the problem just a missing else between the calls?  Is it certain that 
all of the cases are disjoint?

julia