On 03/10/2023 14:08, 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.
I'm not convinced by this change. Can userspace do anything useful with only
a partially filled routes array?
Just silently allowing bad data is asking for problems, IMHO.
Regards,
Hans
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> .../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 9a34e13dfd96..dd48e7e549fb 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, routing->len_routes) *
> + sizeof(*krouting->routes));
> routing->num_routes = krouting->num_routes;
>
> return 0;
