[PATCH 1/1] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value

[PATCH 1/1] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value

[Sakari Ailus]

acpi_graph_get_child_prop_value() is intended to find a child node with a
certain property value pair. The check

	if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
		continue;

is faulty: fwnode_property_read_u32() returns zero on success, not on
failure, leading to comparing values only if the searched property was not
found.

Fixes: 79389a83bc38 ("ACPI / property: Add support for remote endpoints")
Reported-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/acpi/property.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index a65c09c..3963098 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -1052,7 +1052,7 @@ static struct fwnode_handle *acpi_graph_get_child_prop_value(
 	fwnode_for_each_child_node(fwnode, child) {
 		u32 nr;
 
-		if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
+		if (fwnode_property_read_u32(fwnode, prop_name, &nr))
 			continue;
 
 		if (val == nr)
-- 
2.7.4

RE: [PATCH 1/1] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value

[Yang, Hyungwoo]

Hi Sakari,

You forgot "fwnode" => "child".

if (fwnode_property_read_u32(fwnode, prop_name, &nr))
=> if (fwnode_property_read_u32(child, prop_name, &nr))

-Hyungwoo

-----Original Message-----
> From: Sakari Ailus [mailto:sakari.ailus@linux.intel.com] 
> Sent: Tuesday, August 22, 2017 12:01 AM
> To: linux-acpi@vger.kernel.org
> Cc: Yang, Hyungwoo <hyungwoo.yang@intel.com>; Westerberg, Mika <mika.westerberg@intel.com>; rafael@kernel.org
> Subject: [PATCH 1/1] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value
> 
> acpi_graph_get_child_prop_value() is intended to find a child node with a certain property value pair. The check
> 
> 	if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
> 		continue;
> 
> is faulty: fwnode_property_read_u32() returns zero on success, not on failure, leading to comparing values only if the searched property was not found.
> 
> Fixes: 79389a83bc38 ("ACPI / property: Add support for remote endpoints")
> Reported-by: Hyungwoo Yang <hyungwoo.yang@intel.com>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  drivers/acpi/property.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c index a65c09c..3963098 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -1052,7 +1052,7 @@ static struct fwnode_handle *acpi_graph_get_child_prop_value(
>  	fwnode_for_each_child_node(fwnode, child) {
>  		u32 nr;
>  
> -		if (!fwnode_property_read_u32(fwnode, prop_name, &nr))
> +		if (fwnode_property_read_u32(fwnode, prop_name, &nr))
>  			continue;
>  
>  		if (val == nr)
> --
> 2.7.4

Re: [PATCH 1/1] ACPI: device property: Fix node lookup in acpi_graph_get_child_prop_value

[Sakari Ailus]

Yang, Hyungwoo wrote:
>
> Hi Sakari,
>
> You forgot "fwnode" => "child".
>
> if (fwnode_property_read_u32(fwnode, prop_name, &nr))
> => if (fwnode_property_read_u32(child, prop_name, &nr))
>

Oops. I'll send v2...

-- 
Sakari Ailus
sakari.ailus@linux.intel.com