Subject: Re: [PATCH net-next 2/3] virtio_net: remove unused parameter to send_command

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 10 Dec 2013 17:25:11 +0200

On Mon, Dec 09, 2013 at 04:17:40PM -0800, Stephen Hemminger wrote:
> All the code passes NULL for the last sg list (in).
> Simplify by just removing it.
> 
> Signed-off-by: Stephen Hemminger <[email-masked]>

When we need it we can re-add it.

Acked-by: Michael S. Tsirkin <[email-masked]>

> 
> --- a/drivers/net/virtio_net.c	2013-12-09 16:12:36.353164803 -0800
> +++ b/drivers/net/virtio_net.c	2013-12-09 16:12:41.409051865 -0800
> @@ -876,13 +876,12 @@ static netdev_tx_t start_xmit(struct sk_
>   * never fail unless improperly formated.
>   */
>  static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
> -				 struct scatterlist *out,
> -				 struct scatterlist *in)
> +				 struct scatterlist *out)
>  {
>  	struct scatterlist *sgs[4], hdr, stat;
>  	struct virtio_net_ctrl_hdr ctrl;
>  	virtio_net_ctrl_ack status = ~0;
> -	unsigned out_num = 0, in_num = 0, tmp;
> +	unsigned out_num = 0, tmp;
>  
>  	/* Caller should know better */
>  	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
> @@ -895,16 +894,13 @@ static bool virtnet_send_command(struct
>  
>  	for (; out; out = sg_next(out))
>  		sgs[out_num++] = out;
> -	if (in)
> -		sgs[out_num + in_num++] = in;
>  
>  	/* Add return status. */
>  	sg_init_one(&stat, &status, sizeof(status));
> -	sgs[out_num + in_num++] = &stat;
> +	sgs[out_num] = &stat;
>  
> -	BUG_ON(out_num + in_num > ARRAY_SIZE(sgs));
> -	BUG_ON(virtqueue_add_sgs(vi->cvq, sgs, out_num, in_num, vi, GFP_ATOMIC)
> -	       < 0);
> +	BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
> +	BUG_ON(virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC) < 0);
>  
>  	if (unlikely(!virtqueue_kick(vi->cvq)))
>  		return status == VIRTIO_NET_OK;
> @@ -934,8 +930,7 @@ static int virtnet_set_mac_address(struc
>  	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
>  		sg_init_one(&sg, addr->sa_data, dev->addr_len);
>  		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
> -					  VIRTIO_NET_CTRL_MAC_ADDR_SET,
> -					  &sg, NULL)) {
> +					  VIRTIO_NET_CTRL_MAC_ADDR_SET, &sg)) {
>  			dev_warn(&vdev->dev,
>  				 "Failed to set mac address by vq command.\n");
>  			return -EINVAL;
> @@ -1008,7 +1003,7 @@ static void virtnet_ack_link_announce(st
>  {
>  	rtnl_lock();
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_ANNOUNCE,
> -				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL, NULL))
> +				  VIRTIO_NET_CTRL_ANNOUNCE_ACK, NULL))
>  		dev_warn(&vi->dev->dev, "Failed to ack link announce.\n");
>  	rtnl_unlock();
>  }
> @@ -1026,7 +1021,7 @@ static int virtnet_set_queues(struct vir
>  	sg_init_one(&sg, &s, sizeof(s));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
> -				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg, NULL)) {
> +				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
>  		dev_warn(&dev->dev, "Fail to set num of queue pairs to %d\n",
>  			 queue_pairs);
>  		return -EINVAL;
> @@ -1076,16 +1071,14 @@ static void virtnet_set_rx_mode(struct n
>  	sg_init_one(sg, &promisc, sizeof(promisc));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
> -				  VIRTIO_NET_CTRL_RX_PROMISC,
> -				  sg, NULL))
> +				  VIRTIO_NET_CTRL_RX_PROMISC, sg))
>  		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
>  			 promisc ? "en" : "dis");
>  
>  	sg_init_one(sg, &allmulti, sizeof(allmulti));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
> -				  VIRTIO_NET_CTRL_RX_ALLMULTI,
> -				  sg, NULL))
> +				  VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
>  		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
>  			 allmulti ? "en" : "dis");
>  
> @@ -1121,8 +1114,7 @@ static void virtnet_set_rx_mode(struct n
>  		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
> -				  VIRTIO_NET_CTRL_MAC_TABLE_SET,
> -				  sg, NULL))
> +				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
>  		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
>  
>  	kfree(buf);
> @@ -1137,7 +1129,7 @@ static int virtnet_vlan_rx_add_vid(struc
>  	sg_init_one(&sg, &vid, sizeof(vid));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
> -				  VIRTIO_NET_CTRL_VLAN_ADD, &sg, NULL))
> +				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
>  		dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
>  	return 0;
>  }
> @@ -1151,7 +1143,7 @@ static int virtnet_vlan_rx_kill_vid(stru
>  	sg_init_one(&sg, &vid, sizeof(vid));
>  
>  	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
> -				  VIRTIO_NET_CTRL_VLAN_DEL, &sg, NULL))
> +				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))
>  		dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
>  	return 0;
>  }