[04/18] software_node: Enforce parent before child ordering of nodes array for software_node_register_nodes()

Message ID 20201130133129.1024662-5-djrscally@gmail.com
State New
Headers show
Series
  • Add functionality to ipu3-cio2 driver allowing software_node connections to sensors on platforms designed for Windows
Related show

Commit Message

Daniel Scally Nov. 30, 2020, 1:31 p.m.
Registering software_nodes with the .parent member set to point to a
currently unregistered software_node has the potential for problems,
so enforce parent -> child ordering in arrays passed to this function.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Daniel Scally <djrscally@gmail.com>
---
Changes since RFC v3:

	Patch introduced

 drivers/base/swnode.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

Laurent Pinchart Nov. 30, 2020, 4:12 p.m. | #1
On Mon, Nov 30, 2020 at 06:11:52PM +0200, Laurent Pinchart wrote:
> Hi Daniel,
> 
> Thank you for the patch.
> 
> On Mon, Nov 30, 2020 at 01:31:15PM +0000, Daniel Scally wrote:
> > Registering software_nodes with the .parent member set to point to a
> > currently unregistered software_node has the potential for problems,
> > so enforce parent -> child ordering in arrays passed to this function.
> > 
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Signed-off-by: Daniel Scally <djrscally@gmail.com>
> > ---
> > Changes since RFC v3:
> > 
> > 	Patch introduced
> > 
> >  drivers/base/swnode.c | 15 +++++++++++----
> >  1 file changed, 11 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
> > index 615a0c93e116..af7930b3679e 100644
> > --- a/drivers/base/swnode.c
> > +++ b/drivers/base/swnode.c
> > @@ -700,14 +700,21 @@ int software_node_register_nodes(const struct software_node *nodes)
> >  	int i;
> >  
> >  	for (i = 0; nodes[i].name; i++) {
> > +		if (nodes[i].parent)
> > +			if (!software_node_to_swnode(nodes[i].parent)) {
> > +				ret = -EINVAL;
> > +				goto err_unregister_nodes;
> > +			}
> > +
> >  		ret = software_node_register(&nodes[i]);
> > -		if (ret) {
> > -			software_node_unregister_nodes(nodes);
> > -			return ret;
> > -		}
> > +		if (ret)
> > +			goto err_unregister_nodes;
> >  	}
> >  
> >  	return 0;
> 
> I'd add a blank line here.
> 
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

I spoke a bit too soon. Could you update the documentation of the
function to explain this new requirement ?

> > +err_unregister_nodes:
> > +	software_node_unregister_nodes(nodes);
> > +	return ret;
> >  }
> >  EXPORT_SYMBOL_GPL(software_node_register_nodes);
> >  
> 
> -- 
> Regards,
> 
> Laurent Pinchart
Andy Shevchenko Nov. 30, 2020, 5:35 p.m. | #2
On Mon, Nov 30, 2020 at 01:31:15PM +0000, Daniel Scally wrote:
> Registering software_nodes with the .parent member set to point to a
> currently unregistered software_node has the potential for problems,
> so enforce parent -> child ordering in arrays passed to this function.

I agree with Laurent.

...

>  	for (i = 0; nodes[i].name; i++) {
> +		if (nodes[i].parent)
> +			if (!software_node_to_swnode(nodes[i].parent)) {
> +				ret = -EINVAL;
> +				goto err_unregister_nodes;
> +			}
> +

Besides that can we pack these conditionals together?

		if (nodes[i].parent && !software_node_to_swnode(nodes[i].parent)) {


Do we have sane ordering in software_node_unregister_nodes()?

Patch

diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c
index 615a0c93e116..af7930b3679e 100644
--- a/drivers/base/swnode.c
+++ b/drivers/base/swnode.c
@@ -700,14 +700,21 @@  int software_node_register_nodes(const struct software_node *nodes)
 	int i;
 
 	for (i = 0; nodes[i].name; i++) {
+		if (nodes[i].parent)
+			if (!software_node_to_swnode(nodes[i].parent)) {
+				ret = -EINVAL;
+				goto err_unregister_nodes;
+			}
+
 		ret = software_node_register(&nodes[i]);
-		if (ret) {
-			software_node_unregister_nodes(nodes);
-			return ret;
-		}
+		if (ret)
+			goto err_unregister_nodes;
 	}
 
 	return 0;
+err_unregister_nodes:
+	software_node_unregister_nodes(nodes);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(software_node_register_nodes);