[4/4] drm/sun4i: backend: add missing of_node_puts

Submitted by Julia Lawall on Jan. 13, 2019, 8:47 a.m.

Details

Message ID 1547369264-24831-5-git-send-email-Julia.Lawall@lip6.fr
State Accepted
Commit 4bb0e6d7258213d4893c2c876712fbba40e712fe
Headers show
Series "add missing of_node_puts" ( rev: 1 ) in DRI devel

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Commit Message

Julia Lawall Jan. 13, 2019, 8:47 a.m.
The device node iterators perform an of_node_get on each
iteration, so a jump out of the loop requires an of_node_put.

Remote and port also have augmented reference counts, so drop them
on each iteration and at the end of the function, respectively.
Remote is only used for the address it contains, not for the
contents of that address, so the reference count can be dropped
immediately.

The semantic patch that fixes the first part of this problem is
as follows (http://coccinelle.lip6.fr):

// <smpl>
@@
expression root,e;
local idexpression child;
iterator name for_each_child_of_node;
@@

 for_each_available_child_of_node(root, child) {
   ... when != of_node_put(child)
       when != e = child
+  of_node_put(child);
?  break;
   ...
}
... when != child
// </smpl>

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

---
Not tested.

 drivers/gpu/drm/sun4i/sun4i_backend.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index 9e9255e..a021bab 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -786,17 +786,18 @@  static struct sun4i_frontend *sun4i_backend_find_frontend(struct sun4i_drv *drv,
 		remote = of_graph_get_remote_port_parent(ep);
 		if (!remote)
 			continue;
+		of_node_put(remote);
 
 		/* does this node match any registered engines? */
 		list_for_each_entry(frontend, &drv->frontend_list, list) {
 			if (remote == frontend->node) {
-				of_node_put(remote);
 				of_node_put(port);
+				of_node_put(ep);
 				return frontend;
 			}
 		}
 	}
-
+	of_node_put(port);
 	return ERR_PTR(-EINVAL);
 }
 

Comments

On Sun, Jan 13, 2019 at 09:47:44AM +0100, Julia Lawall wrote:
> The device node iterators perform an of_node_get on each
> iteration, so a jump out of the loop requires an of_node_put.
> 
> Remote and port also have augmented reference counts, so drop them
> on each iteration and at the end of the function, respectively.
> Remote is only used for the address it contains, not for the
> contents of that address, so the reference count can be dropped
> immediately.
> 
> The semantic patch that fixes the first part of this problem is
> as follows (http://coccinelle.lip6.fr):
> 
> // <smpl>
> @@
> expression root,e;
> local idexpression child;
> iterator name for_each_child_of_node;
> @@
> 
>  for_each_available_child_of_node(root, child) {
>    ... when != of_node_put(child)
>        when != e = child
> +  of_node_put(child);
> ?  break;
>    ...
> }
> ... when != child
> // </smpl>
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>

Applied, thanks!
Maxime