On Thu, Oct 22, 2015 at 01:27:28AM -0400, Jason Wang wrote:
> This path introduces a helper which can give a hint for whether or not
> there's a work queued in the work list.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vhost/vhost.c | 6 ++++++
> drivers/vhost/vhost.h | 1 +
> 2 files changed, 7 insertions(+)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index eec2f11..d42d11e 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -245,6 +245,12 @@ void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
> }
> EXPORT_SYMBOL_GPL(vhost_work_queue);
>
> +bool vhost_has_work(struct vhost_dev *dev)
> +{
> + return !list_empty(&dev->work_list);
> +}
> +EXPORT_SYMBOL_GPL(vhost_has_work);
> +
> void vhost_poll_queue(struct vhost_poll *poll)
> {
> vhost_work_queue(poll->dev, &poll->work);
This doesn't take a lock so it's unreliable.
I think it's ok in this case since it's just
an optimization - but pls document this.
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 4772862..ea0327d 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -37,6 +37,7 @@ struct vhost_poll {
>
> void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn);
> void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work);
> +bool vhost_has_work(struct vhost_dev *dev);
>
> void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
> unsigned long mask, struct vhost_dev *dev);
> --
> 1.8.3.1
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