Re: [PATCH v4 1/3] media: v4l2-ctrls: Don't reset handler's error in v4l2_ctrl_handler_free()

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Mon, Jun 23, 2025 at 03:23:12PM +0300, Sakari Ailus wrote:
> It's a common pattern in drivers to free the control handler's resources
> and then return the handler's error code on drivers' error handling paths.
> Alas, the v4l2_ctrl_handler_free() function also zeroes the error field,
> effectively indicating successful return to the caller.
> 
> There's no apparent need to touch the error field while releasing the
> control handler's resources and cleaning up stale pointers. Not touching
> the handler's error field is a more certain way to address this problem
> than changing all the users, in which case the pattern would be likely to
> re-emerge in new drivers.
> 
> Do just that, don't touch the control handler's error field in
> v4l2_ctrl_handler_free().
> 
> Fixes: 0996517cf8ea ("V4L/DVB: v4l2: Add new control handling framework")
> Cc: stable@vger.kernel.org
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reviewed-by: Hans Verkuil <hverkuil@xs4all.nl>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
>  drivers/media/v4l2-core/v4l2-ctrls-core.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> index b45809a82f9a..d28596c720d8 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> @@ -1661,7 +1661,6 @@ void v4l2_ctrl_handler_free(struct v4l2_ctrl_handler *hdl)
>  	kvfree(hdl->buckets);
>  	hdl->buckets = NULL;
>  	hdl->cached = NULL;
> -	hdl->error = 0;
>  	mutex_unlock(hdl->lock);
>  	mutex_destroy(&hdl->_lock);
>  }

-- 
Regards,

Laurent Pinchart