4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 4bb0e6d7258213d4893c2c876712fbba40e712fe ]
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 Signed-off-by: Maxime Ripard maxime.ripard@bootlin.com Link: https://patchwork.freedesktop.org/patch/msgid/1547369264-24831-5-git-send-em... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/sun4i/sun4i_backend.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c index d7950b52a1fd9..e30b1f5b9d91a 100644 --- a/drivers/gpu/drm/sun4i/sun4i_backend.c +++ b/drivers/gpu/drm/sun4i/sun4i_backend.c @@ -717,17 +717,18 @@ 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); }