* @prio: priority of the file handler, as defined by &enum v4l2_priority
*
* @wait: event' s wait queue
+ * @subscribe_lock: serialise changes to the subscribed list; guarantee that
+ * the add and del event callbacks are orderly called
* @subscribed: list of subscribed events
* @available: list of events waiting to be dequeued
* @navailable: number of available events at @available list
* @sequence: event sequence number
+ *
* @m2m_ctx: pointer to &struct v4l2_m2m_ctx
*/
struct v4l2_fh {
/* Events */
wait_queue_head_t wait;
+ struct mutex subscribe_lock;
struct list_head subscribed;
struct list_head available;
unsigned int navailable;