Re: [RFC v2 4/4] v4l: events: Don't sleep in dequeue if none are subscribed

[Hans Verkuil <hverkuil@xs4all.nl>]

On 10/02/13 15:45, Sakari Ailus wrote:
> Dequeueing events was is entirely possible even if none are subscribed,
> leading to sleeping indefinitely. Fix this by returning -ENOENT when no
> events are subscribed.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> ---
>   drivers/media/v4l2-core/v4l2-event.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-event.c b/drivers/media/v4l2-core/v4l2-event.c
> index b53897e..553a800 100644
> --- a/drivers/media/v4l2-core/v4l2-event.c
> +++ b/drivers/media/v4l2-core/v4l2-event.c
> @@ -77,10 +77,17 @@ int v4l2_event_dequeue(struct v4l2_fh *fh, struct v4l2_event *event,
>   		mutex_unlock(fh->vdev->lock);
>
>   	do {
> -		ret = wait_event_interruptible(fh->wait,
> -					       fh->navailable != 0);
> +		bool subscribed;

Can you add an empty line here?

> +		ret = wait_event_interruptible(
> +			fh->wait,
> +			fh->navailable != 0 ||
> +			!(subscribed = v4l2_event_has_subscribed(fh)));
>   		if (ret < 0)
>   			break;
> +		if (!subscribed) {
> +			ret = -EIO;

Shouldn't this be -ENOENT?

> +			break;
> +		}
>
>   		ret = __v4l2_event_dequeue(fh, event);
>   	} while (ret == -ENOENT);
>

Regards,

	Hans