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

[Sakari Ailus <sakari.ailus@linux.intel.com>]

On Tue, Sep 26, 2023 at 12:32:02AM +0300, Laurent Pinchart wrote:
> 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) *

Thanks. I'll address this in v5.

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

-- 
Sakari Ailus