Re: [PATCH 4/6] virtio_net: allow specifying context for rx

[Cornelia Huck]

On Wed, 29 Mar 2017 23:48:54 +0300
"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:

> With mergeable buffers we never use s/g for rx,
> so allow specifying context in that case.
> 
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
>  drivers/net/virtio_net.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 6802169..340f737 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2044,6 +2044,7 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  	int ret = -ENOMEM;
>  	int i, total_vqs;
>  	const char **names;
> +	const bool *ctx;
>  
>  	/* We expect 1 RX virtqueue followed by 1 TX virtqueue, followed by
>  	 * possible N-1 RX/TX queue pairs used in multiqueue mode, followed by
> @@ -2062,6 +2063,13 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  	names = kmalloc(total_vqs * sizeof(*names), GFP_KERNEL);
>  	if (!names)
>  		goto err_names;
> +	if (vi->mergeable_rx_bufs) {
> +		ctx = kzalloc(total_vqs * sizeof(*ctx), GFP_KERNEL);
> +		if (!ctx)
> +			goto err_ctx;
> +	} else {
> +		ctx = NULL;
> +	}
>  
>  	/* Parameters for control virtqueue, if any */
>  	if (vi->has_cvq) {
> @@ -2077,9 +2085,12 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  		sprintf(vi->sq[i].name, "output.%d", i);
>  		names[rxq2vq(i)] = vi->rq[i].name;
>  		names[txq2vq(i)] = vi->sq[i].name;
> +		if (ctx)
> +			ctx[rxq2vq(i)] = true;
>  	}
>  
> -	ret = virtio_find_vqs(vi->vdev, total_vqs, vqs, callbacks, names, NULL);
> +	ret = vi->vdev->config->find_vqs(vi->vdev, total_vqs, vqs, callbacks,
> +					 names, ctx, NULL);

virtio_find_vqs_ctx()? (Needs to be exported, obviously.)

>  	if (ret)
>  		goto err_find;
>  
> @@ -2101,6 +2112,8 @@ static int virtnet_find_vqs(struct virtnet_info *vi)
>  	return 0;
>  
>  err_find:
> +	kfree(ctx);
> +err_ctx:
>  	kfree(names);
>  err_names:
>  	kfree(callbacks);