[media] v4l: Allow changing control handler lock
Allow choosing the lock used by the control handler. This may be handy
sometimes when a driver providing multiple subdevs does not want to use
several locks to serialise its functions.
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
index c6f6b4c..dde6fba 100644
--- a/include/media/v4l2-ctrls.h
+++ b/include/media/v4l2-ctrls.h
@@ -167,7 +167,9 @@
/** struct v4l2_ctrl_handler - The control handler keeps track of all the
* controls: both the controls owned by the handler and those inherited
* from other handlers.
+ * @_lock: Default for "lock".
* @lock: Lock to control access to this handler and its controls.
+ * May be replaced by the user right after init.
* @ctrls: The list of controls owned by this handler.
* @ctrl_refs: The list of control references.
* @cached: The last found control reference. It is common that the same
@@ -178,7 +180,8 @@
* @error: The error code of the first failed control addition.
*/
struct v4l2_ctrl_handler {
- struct mutex lock;
+ struct mutex _lock;
+ struct mutex *lock;
struct list_head ctrls;
struct list_head ctrl_refs;
struct v4l2_ctrl_ref *cached;
@@ -455,7 +458,7 @@
*/
static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
{
- mutex_lock(&ctrl->handler->lock);
+ mutex_lock(ctrl->handler->lock);
}
/** v4l2_ctrl_lock() - Helper function to unlock the handler
@@ -464,7 +467,7 @@
*/
static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
{
- mutex_unlock(&ctrl->handler->lock);
+ mutex_unlock(ctrl->handler->lock);
}
/** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.