[media] uvcvideo: Ignore entities for terminals with no supported format

If a streaming interface has no supported format, the driver won't
create a video device for the associated terminal. Fix an oops by
ignoring that terminal when creating links between entities.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 21 insertions, 13 deletions

diff --git a/drivers/media/video/uvc/uvc_entity.c b/drivers/media/video/uvc/uvc_entity.c
index c3ab0c813be2..48fea373c25a 100644
--- a/drivers/media/video/uvc/uvc_entity.c
+++ b/drivers/media/video/uvc/uvc_entity.c
@@ -27,14 +27,20 @@ static int uvc_mc_register_entity(struct uvc_video_chain *chain,
         struct uvc_entity *entity)
 {
         const u32 flags = MEDIA_LNK_FL_ENABLED | MEDIA_LNK_FL_IMMUTABLE;
-        struct uvc_entity *remote;
+        struct media_entity *sink;
         unsigned int i;
-        u8 remote_pad;
-        int ret = 0;
+        int ret;
+
+        sink = (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
+             ? (entity->vdev ? &entity->vdev->entity : NULL)
+             : &entity->subdev.entity;
+        if (sink == NULL)
+                return 0;
 
         for (i = 0; i < entity->num_pads; ++i) {
                 struct media_entity *source;
-                struct media_entity *sink;
+                struct uvc_entity *remote;
+                u8 remote_pad;
 
                 if (!(entity->pads[i].flags & MEDIA_PAD_FL_SINK))
                         continue;
@@ -43,10 +49,11 @@ static int uvc_mc_register_entity(struct uvc_video_chain *chain,
                 if (remote == NULL)
                         return -EINVAL;
 
-                source = (UVC_ENTITY_TYPE(remote) == UVC_TT_STREAMING)
-                       ? &remote->vdev->entity : &remote->subdev.entity;
-                sink = (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
-                     ? &entity->vdev->entity : &entity->subdev.entity;
+                source = (UVC_ENTITY_TYPE(remote) != UVC_TT_STREAMING)
+                       ? (remote->vdev ? &remote->vdev->entity : NULL)
+                       : &remote->subdev.entity;
+                if (source == NULL)
+                        continue;
 
                 remote_pad = remote->num_pads - 1;
                 ret = media_entity_create_link(source, remote_pad,
@@ -55,11 +62,10 @@ static int uvc_mc_register_entity(struct uvc_video_chain *chain,
                         return ret;
         }
 
-        if (UVC_ENTITY_TYPE(entity) != UVC_TT_STREAMING)
-                ret = v4l2_device_register_subdev(&chain->dev->vdev,
-                                                  &entity->subdev);
+        if (UVC_ENTITY_TYPE(entity) == UVC_TT_STREAMING)
+                return 0;
 
-        return ret;
+        return v4l2_device_register_subdev(&chain->dev->vdev, &entity->subdev);
 }
 
 static struct v4l2_subdev_ops uvc_subdev_ops = {
@@ -84,9 +90,11 @@ static int uvc_mc_init_entity(struct uvc_entity *entity)
 
                 ret = media_entity_init(&entity->subdev.entity,
                                         entity->num_pads, entity->pads, 0);
-        } else
+        } else if (entity->vdev != NULL) {
                 ret = media_entity_init(&entity->vdev->entity,
                                         entity->num_pads, entity->pads, 0);
+        } else
+                ret = 0;
 
         return ret;
 }