Re: [PATCH v14 22/34] media: subdev: add v4l2_subdev_set_routing helper()

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

On 25/09/2022 14:26, Sakari Ailus wrote:
> Moi,
> 
> On Wed, Aug 31, 2022 at 05:13:45PM +0300, Tomi Valkeinen wrote:
>> Add a helper function to set the subdev routing. The helper can be used
>> from subdev driver's set_routing op to store the routing table.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
>> ---
>>   drivers/media/v4l2-core/v4l2-subdev.c | 28 +++++++++++++++++++++++++++
>>   include/media/v4l2-subdev.h           | 16 +++++++++++++++
>>   2 files changed, 44 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index 1ce9a7dc0c6e..f3f872c72180 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -1180,6 +1180,34 @@ int v4l2_subdev_get_fmt(struct v4l2_subdev *sd, struct v4l2_subdev_state *state,
>>   }
>>   EXPORT_SYMBOL_GPL(v4l2_subdev_get_fmt);
>>   
>> +int v4l2_subdev_set_routing(struct v4l2_subdev *sd,
>> +			    struct v4l2_subdev_state *state,
>> +			    const struct v4l2_subdev_krouting *routing)
>> +{
>> +	struct v4l2_subdev_krouting *dst = &state->routing;
>> +	const struct v4l2_subdev_krouting *src = routing;
>> +	struct v4l2_subdev_krouting new_routing = { 0 };
>> +
>> +	lockdep_assert_held(state->lock);
>> +
>> +	if (src->num_routes > 0) {
>> +		new_routing.routes = kmemdup(src->routes,
>> +			src->num_routes * sizeof(*src->routes),
> 
> This can overflow.

Right. In practice it won't happen as the num_routes has been limited to 
256, but no harm to check for overflow here.

  Tomi