Hi Andrzej,
Thanks for the patchset!
On Thu, May 16, 2013 at 10:14:33AM +0200, Andrzej Hajda wrote:
> This patch adds managed version of initialization
> function for v4l2 control handler.
>
> Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
> v3:
> - removed managed cleanup
> v2:
> - added missing struct device forward declaration,
> - corrected few comments
> ---
> drivers/media/v4l2-core/v4l2-ctrls.c | 32 ++++++++++++++++++++++++++++++++
> include/media/v4l2-ctrls.h | 16 ++++++++++++++++
> 2 files changed, 48 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index ebb8e48..f47ccfa 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1421,6 +1421,38 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
> }
> EXPORT_SYMBOL(v4l2_ctrl_handler_free);
>
> +static void devm_v4l2_ctrl_handler_release(struct device *dev, void *res)
> +{
> + struct v4l2_ctrl_handler **hdl = res;
> +
> + v4l2_ctrl_handler_free(*hdl);
v4l2_ctrl_handler_free() acquires hdl->mutex which is independent of the
existence of hdl. By default hdl->lock is in the handler, but it may also be
elsewhere, e.g. in a driver-specific device struct such as struct
smiapp_sensor defined in drivers/media/i2c/smiapp/smiapp.h. I wonder if
anything guarantees that hdl->mutex still exists at the time the device is
removed.
I have to say I don't think it's neither meaningful to acquire that mutex in
v4l2_ctrl_handler_free(), though, since the whole going to be freed next
anyway: reference counting would be needed to prevent bad things from
happening, in case the drivers wouldn't take care of that.
> +}
> +
--
Kind regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
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