Hi Sakari,
On 03/06/2012 05:32 PM, Sakari Ailus wrote:
> 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@xxxxxx>
> ---
> drivers/media/video/adp1653.c | 8 +++---
> drivers/media/video/v4l2-ctrls.c | 39 +++++++++++++++++++------------------
> drivers/media/video/vivi.c | 4 +-
> include/media/v4l2-ctrls.h | 9 +++++--
> 4 files changed, 32 insertions(+), 28 deletions(-)
...
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 533315b..71abac0 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -168,7 +168,9 @@ struct v4l2_ctrl_ref {
> /** 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
> @@ -179,7 +181,8 @@ struct v4l2_ctrl_ref {
> * @error: The error code of the first failed control addition.
> */
> struct v4l2_ctrl_handler {
> - struct mutex lock;
> + struct mutex _lock;
> + struct mutex *lock;
I think we have an issue here. All drivers that reference ctrl_handler.lock
directly need to be updated, since the 'lock' member of struct v4l2_ctrl_handler
is no a pointer. So insted
mutex_lock(&ctrl_handler.lock);
they should now do
mutex_lock(ctrl_handler.lock);
Or am I missing something ?
For example, I'm getting following error:
drivers/media/video/s5p-fimc/fimc-core.c: In function ‘fimc_ctrls_activate’:
drivers/media/video/s5p-fimc/fimc-core.c:678: warning: passing argument 1 of ‘mutex_lock’ from incompatible pointer type
include/linux/mutex.h:152: note: expected ‘struct mutex *’ but argument is of type ‘struct mutex **’
drivers/media/video/s5p-fimc/fimc-core.c:697: warning: passing argument 1 of ‘mutex_unlock’ from incompatible pointer type
include/linux/mutex.h:169: note: expected ‘struct mutex *’ but argument is of type ‘struct mutex **’
AFAICT only vivi and s5p-fimc drivers use the control handler lock
directly, so I can prepare a patch updating those drivers.
> struct list_head ctrls;
> struct list_head ctrl_refs;
> struct v4l2_ctrl_ref *cached;
> @@ -456,7 +459,7 @@ void v4l2_ctrl_grab(struct v4l2_ctrl *ctrl, bool grabbed);
> */
> 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
> @@ -465,7 +468,7 @@ static inline void v4l2_ctrl_lock(struct v4l2_ctrl *ctrl)
> */
> 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.
--
Regards,
Sylwester
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