On Thu, Sep 05, 2019 at 03:48:49PM -0400, Vivek Goyal wrote:
> +static void virtio_fs_drain_queue(struct virtio_fs_vq *fsvq)
> +{
> +	WARN_ON(fsvq->in_flight < 0);
> +
> +	/* Wait for in flight requests to finish.*/
> +	while (1) {
> +		spin_lock(&fsvq->lock);
> +		if (!fsvq->in_flight) {
> +			spin_unlock(&fsvq->lock);
> +			break;
> +		}
> +		spin_unlock(&fsvq->lock);
> +		usleep_range(1000, 2000);
> +	}

I think all contexts that call this allow sleeping so we could avoid
usleep here.