在 2021/11/2 23:03, Maxime Ripard 写道:
Hi,
On Tue, Nov 02, 2021 at 04:46:28AM -0400, He Ying wrote:
From the comments of drm_for_each_connector_iter(), we know
that "connector is only valid within the list body, if you
want to use connector after calling drm_connector_list_iter_end()
then you need to grab your own reference first using
drm_connector_get()". So fix the wrong use of connector
according to the comments and then call drm_connector_put()
after using connector finishes.
Signed-off-by: He Ying <heying24@xxxxxxxxxx>
---
V2:
Use proper subject prefix
drivers/gpu/drm/sun4i/sun4i_tcon.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/sun4i/sun4i_tcon.c b/drivers/gpu/drm/sun4i/sun4i_tcon.c
index 9f06dec0fc61..24fa6784ee5f 100644
--- a/drivers/gpu/drm/sun4i/sun4i_tcon.c
+++ b/drivers/gpu/drm/sun4i/sun4i_tcon.c
@@ -47,12 +47,12 @@ static struct drm_connector *sun4i_tcon_get_connector(const struct drm_encoder *
drm_connector_list_iter_begin(encoder->dev, &iter);
drm_for_each_connector_iter(connector, &iter)
if (connector->encoder == encoder) {
- drm_connector_list_iter_end(&iter);
- return connector;
+ drm_connector_get(connector);
+ break;
}
drm_connector_list_iter_end(&iter);
- return NULL;
+ return connector;
Connector might be uninitialized if we don't find one here
Connector should be NULL if we don't find one. The code is
#define drm_for_each_connector_iter(connector, iter) \
while ((connector = drm_connector_list_iter_next(iter)))
So, when we don't break from the while body, connector
can only be NULL.
}
static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
@@ -65,6 +65,7 @@ static int sun4i_tcon_get_pixel_depth(const struct drm_encoder *encoder)
return -EINVAL;
info = &connector->display_info;
+ drm_connector_put(connector);
if (info->num_bus_formats != 1)
We're still accessing connector->display_info here, but it might have been
freed already.
Agree. I'll place it after using 'info' finishes in v3.
Maxime
