Re: [PATCH v4 21/23] media: uapi: Allow a larger number of routes than there's room for

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

Hi Sakari,

Thank you for the patch.

On Fri, Sep 22, 2023 at 05:22:37PM +0300, Sakari Ailus wrote:
> On VIDIOC_SUBDEV_[GS]_ROUTING, only return as many routes back to the user
> as there's room. Do not consider it an error if more routes existed.
> Simply inform the user there are more routes.
> 
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>  .../userspace-api/media/v4l/vidioc-subdev-g-routing.rst   | 4 ----
>  drivers/media/v4l2-core/v4l2-subdev.c                     | 8 ++------
>  2 files changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst
> index ced53ea5f23c..99d3c15fd759 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-routing.rst
> @@ -145,10 +145,6 @@ On success 0 is returned, on error -1 and the ``errno`` variable is set
>  appropriately. The generic error codes are described at the
>  :ref:`Generic Error Codes <gen-errors>` chapter.
>  
> -ENOSPC
> -   The application provided ``num_routes`` is not big enough to contain
> -   all the available routes the subdevice exposes.
> -
>  EINVAL
>     The sink or source pad identifiers reference a non-existing pad, or reference
>     pads of different types (ie. the sink_pad identifiers refers to a source pad).
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 1bcc96cde6da..7871ec8a66d1 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -956,14 +956,10 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg,
>  
>  		krouting = &state->routing;
>  
> -		if (routing->len_routes < krouting->num_routes) {
> -			routing->num_routes = krouting->num_routes;
> -			return -ENOSPC;
> -		}
> -
>  		memcpy((struct v4l2_subdev_route *)(uintptr_t)routing->routes,
>  		       krouting->routes,
> -		       krouting->num_routes * sizeof(*krouting->routes));
> +		       min(krouting->num_routes, krouting->len_routes) *

This should be

		       min(krouting->num_routes, routing->len_routes) *

> +		       sizeof(*krouting->routes));
>  		routing->num_routes = krouting->num_routes;
>  
>  		return 0;

-- 
Regards,

Laurent Pinchart