On 05/14/2012 05:27 PM, Sylwester Nawrocki wrote:
> 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 now a pointer. So instead
>
> 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.
OK, vivi and adp1653 are already modified in this patch, so s5p-fimc
seems the only one left. I'll fix that.
Regards,
Sylwester
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