Re: [PATCH v9 32/32] virtio_net: support set_ringparam

From: Jason Wang <jasowang@redhat.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
	virtualization@lists.linux-foundation.org
Cc: Jeff Dike <jdike@addtoit.com>,
	Richard Weinberger <richard@nod.at>,
	Anton Ivanov <anton.ivanov@cambridgegreys.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Hans de Goede <hdegoede@redhat.com>,
	Mark Gross <markgross@kernel.org>,
	Vadim Pasternak <vadimp@nvidia.com>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Cornelia Huck <cohuck@redhat.com>,
	Halil Pasic <pasic@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jesper Dangaard Brouer <hawk@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	Johannes Berg <johannes.berg@intel.com>,
	Vincent Whitchurch <vincent.whitchurch@axis.com>,
	linux-um@lists.infradead.org, netdev@vger.kernel.org,
	platform-driver-x86@vger.kernel.org,
	linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org,
	kvm@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH v9 32/32] virtio_net: support set_ringparam
Date: Wed, 13 Apr 2022 16:06:33 +0800	[thread overview]
Message-ID: <96d1fe97-2e8a-ae8a-a35f-bba2ce0f44b4@redhat.com> (raw)
In-Reply-To: <20220406034346.74409-33-xuanzhuo@linux.alibaba.com>

在 2022/4/6 上午11:43, Xuan Zhuo 写道:
> Support set_ringparam based on virtio queue reset.
>
> Users can use ethtool -G eth0 <ring_num> to modify the ring size of
> virtio-net.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

Acked-by: Jason Wang <jasowang@redhat.com>

(One thing that I see is that, when resize fails, the param reported via 
get_ringparam might be wrong, this is a corner case but might worth to 
fix in the future).

> ---
>   drivers/net/virtio_net.c | 47 ++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 47 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index ba6859f305f7..37e4e27f1e4e 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2264,6 +2264,52 @@ static void virtnet_get_ringparam(struct net_device *dev,
>   	ring->tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);
>   }
>   
> +static int virtnet_set_ringparam(struct net_device *dev,
> +				 struct ethtool_ringparam *ring,
> +				 struct kernel_ethtool_ringparam *kernel_ring,
> +				 struct netlink_ext_ack *extack)
> +{
> +	struct virtnet_info *vi = netdev_priv(dev);
> +	u32 rx_pending, tx_pending;
> +	struct receive_queue *rq;
> +	struct send_queue *sq;
> +	int i, err;
> +
> +	if (ring->rx_mini_pending || ring->rx_jumbo_pending)
> +		return -EINVAL;
> +
> +	rx_pending = virtqueue_get_vring_size(vi->rq[0].vq);
> +	tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);
> +
> +	if (ring->rx_pending == rx_pending &&
> +	    ring->tx_pending == tx_pending)
> +		return 0;
> +
> +	if (ring->rx_pending > virtqueue_get_vring_max_size(vi->rq[0].vq))
> +		return -EINVAL;
> +
> +	if (ring->tx_pending > virtqueue_get_vring_max_size(vi->sq[0].vq))
> +		return -EINVAL;
> +
> +	for (i = 0; i < vi->max_queue_pairs; i++) {
> +		rq = vi->rq + i;
> +		sq = vi->sq + i;
> +
> +		if (ring->tx_pending != tx_pending) {
> +			err = virtnet_tx_resize(vi, sq, ring->tx_pending);
> +			if (err)
> +				return err;
> +		}
> +
> +		if (ring->rx_pending != rx_pending) {
> +			err = virtnet_rx_resize(vi, rq, ring->rx_pending);
> +			if (err)
> +				return err;
> +		}
> +	}
> +
> +	return 0;
> +}
>   
>   static void virtnet_get_drvinfo(struct net_device *dev,
>   				struct ethtool_drvinfo *info)
> @@ -2497,6 +2543,7 @@ static const struct ethtool_ops virtnet_ethtool_ops = {
>   	.get_drvinfo = virtnet_get_drvinfo,
>   	.get_link = ethtool_op_get_link,
>   	.get_ringparam = virtnet_get_ringparam,
> +	.set_ringparam = virtnet_set_ringparam,
>   	.get_strings = virtnet_get_strings,
>   	.get_sset_count = virtnet_get_sset_count,
>   	.get_ethtool_stats = virtnet_get_ethtool_stats,