media: media-request: add media_request_object_find

Add media_request_object_find to find a request object inside a
request based on ops and priv values.

Objects of the same type (vb2 buffer, control handler) will have
the same ops value. And objects that refer to the same 'parent'
object (e.g. the v4l2_ctrl_handler that has the current driver
state) will have the same priv value.

The caller has to call media_request_object_put() for the returned
object since this function increments the refcount.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/drivers/media/media-request.c b/drivers/media/media-request.c
index 8d3c7360c8f3..4b0ce8fde7c9 100644
--- a/drivers/media/media-request.c
+++ b/drivers/media/media-request.c
@@ -342,6 +342,31 @@ static void media_request_object_release(struct kref *kref)
 	obj->ops->release(obj);
 }
 
+struct media_request_object *
+media_request_object_find(struct media_request *req,
+			  const struct media_request_object_ops *ops,
+			  void *priv)
+{
+	struct media_request_object *obj;
+	struct media_request_object *found = NULL;
+	unsigned long flags;
+
+	if (WARN_ON(!ops || !priv))
+		return NULL;
+
+	spin_lock_irqsave(&req->lock, flags);
+	list_for_each_entry(obj, &req->objects, list) {
+		if (obj->ops == ops && obj->priv == priv) {
+			media_request_object_get(obj);
+			found = obj;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&req->lock, flags);
+	return found;
+}
+EXPORT_SYMBOL_GPL(media_request_object_find);
+
 void media_request_object_put(struct media_request_object *obj)
 {
 	kref_put(&obj->kref, media_request_object_release);